한국정밀공학회:학술대회논문집 (Proceedings of the Korean Society of Precision Engineering Conference) (Proceedings of the Korean Society of Precision Engineering Conference)
한국정밀공학회 (Korean Society for Precision Engineering)
- 반년간
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- 2005-8446(pISSN)
과학기술표준분류
- 기계 > 정밀생산기계
한국정밀공학회 2005년도 춘계학술대회 논문집
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The grinding process is replacing lapping and etching process because significant cost savings and performance improvemnets is possible. This paper presents the experimental results of wafer grinding. A three-variable two-level full factorial design was employed to reveal the main effects as well as the interaction effects of three process parameters such as wheel rotational speed, chuck table rotational speed and feed rate on TTV and STIR of wafers. The chuck table rotaional speed was a significant factor and the interaction effects was significant. The ground wafer shape was affected by surface shape of chuck table.
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In this study, the ultra precision centerless grinder for ferrule grinding was designed. As the good-qualified ferrule is required a precise and fine grinding, grinding machine for ferrule must have a high accuracy and a sufficient stiffness. The centerless grinder is composed of the high damping concrete bed, grinding wheel spindle unit, regulating wheel spindle unit, feeding table and dressing unit. For a newly developed centerless grinder, hydrostatic system with high precision feeding and high stiffness was proposed. The grinding and regulating wheel spindle units were composed of hydrostatic spindle and feeding table was hydrostatic table. The prototype of hydrostatic table was manufactured and tested.
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This report deals with a feeding system of the Coaxal grinding machine, processing optical ferrule. This report also examines the applicability of using the feeding system for the Coaxial grinding machine, by mean of conducting performance estimation. The results are as follow; Repeatability of regulating wheel is
$17{\mu}m$ , R/W rotation accuracy is between$30\;\~\;40{\mu}m$ . This means 'Rotation accuracy' is lower than the concentricity level. Backlash generation level at the feeding system of the grinding wheel is under$1{\mu}m$ , thereby positioning accuracy is controlled within$2{\mu}m$ In terms of repeatability, you can find occasional error at the returning process from the starting point. This error is resulted from the measurement tolerance of the starting point sensor. We will get the repeatability level under control by$1{\mu}m$ , through improving the soft-ware used and up-grading the sensor at the starting point. -
As consumer in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, The development of ultra-precision grinding system and manufacturing properties for the aspheric surface micro lens are described. In the work reported in this paper, and ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the surface roughness and profiles accuracy. And this paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. It results was that a form accuracy of
$3\;{\mu}m$ P-V and a surface roughness of$0.1\;{\mu}m\;R_{max}$ . -
As the optical communication industry is developed, the demand of optical communication part is increasing.
$ZrO_2$ ceramic ferrule is very important part which can determines the transmission efficiency and information quality to connect the optical fibers. In general$ZrO_2$ ceramic ferrule is manufactured by grinding process because the demands precision is very high. And the co-axle grinding process of$ZrO_2$ ceramic ferrule is to make its concentricity all of uniform before centerless grinding. When co-axle grinding of ferrule supported by two pin, pin chucking alignment accuracy is very important. This paper deals with the analysis of the chucking alignment experiment with parallel error on the micro feeding equipment. Thus, if possible be finding highly good the chucking alignment of two pin. -
Consolidation of ceramic particles at room temperature. Reduction of crystallite size and formation of nano-crystalline. Applicable to Integrate functionalceramic materials with metals and Si structure and to fabricate MEMS devises
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This paper introduces an approach to multi-layered product knowledge model for collaborative engineering environment. The participants in collaborative engineering want to share and reason product knowledge through internet without any heterogeneity and ambiguity. However the previous knowledge models are limited in providing those aspects. In this paper, the collaborative engineering domain is analyzed and then the product knowledge is organized into four levels such as product context model, product specific model, product design model and product manufacturing model. The four levels are represented by first-order logic in layered fashion. The concepts and the instances of a formal ontology are used for recursive representation of the four levels. The instances of the concepts of an upper level like product context model are considered as the concepts of an adjacent lower level like product specific model, and this mechanism is applied to the other levels. These logic representations are integrated with the schema and the instances of a relational database. OWL representation of the four levels is defined through the integration of the logic representation and OWL primitives. The four product knowledge models have their major representation according to the characteristics of each model. This approach enables engineer to share product knowledge through internet without any ambiguity and utilize it as basis for additional reasoning.
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More than five pulleys are used in an automobile, such as crankshaft, water pump, air-con compressor, fan and power steering pump pulley. These pulleys are parts that need durability until retiring a car. But there is no design criterion for durability, so pulleys are designed by the experience of designer and trial and error. So, in this study, we carried out stress analysis at durability test condition and compared analysis results to durability test results. It is found that the design criterion for durability is defined as a safety factor and a safety factor is different according to the distance between the center line of v-grooves and the mating surface.
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A design for the front section of an excavator requires kinematic and kinetic mechanism consideration for several configurations. Key parameters for an appropriate configuration can be obtained through a mechanical verification and numerical formulation with a design expert's know-how. In this paper, we propose a knowledge-based system with an expert-shell(CATIA) and Visual Basic to assist for the design of the front section of an excavator. The designers can achieve more efficient design through a CAD model, implemented design knowledge, and a user friendly interface. The implemented design knowledge is retrieved through the whole design process from an early design stage to a detailed design stage based on the multiple levels of abstraction scheme.
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In this paper, the structural design optimization of a wafer grinding machine using a multi-step optimization with genetic algorithm is presented. The design problem, in this study, is to find out the optimum configuration and dimensions of structural members which minimize the static compliance, the dynamic compliance, and the weight of the machine structure simultaneously under several design constraints. The first design step is shape optimization, in which the best structural configuration is found by getting rid of structural members that have no contributions to the design objectives from the given initial design configuration. The second and third steps are sizing optimization. The second design step gives a set of good design solutions having higher fitness for lightweight and minimum static compliance. Finally the best solution, which has minimum dynamic compliance and weight, is extracted among those good solution set. The proposed design optimization method was successfully applied to the structural design optimization of a high precision wafer grinding machine. After optimization, both static and dynamic compliances are reduced more than
$92\%\;and\;93\%$ compared with the initial design, which was designed empirically by experienced engineers. Moreover the weight of the optimized structure are also slightly reduced than before. -
Design and estimation of a spindle system which was composed of grinding spindle and regulating spindle for the centerless grinding of ferrule was performed and prototypes of each spindle were manufactured. Loop stiffness of the spindle system was 130 N/
${\mu}m$ . Although the value was lower than the target value of 150 N/${\mu}m$ , as there included 20% of the safety factor, it was enough to machine the ferrule. Rotational accuracies of each spindle were about 0.2${\mu}m$ at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm(regulating spindle). Temperature rises at the same speed were about$4.4\;\~\;4.7^{\circ}C$ in the case of grinding spindle and$1.8^{\circ}C$ in the case of regulating spindle, which were well agreed with the designed value. From these results, it was estimated that the prototype of spindle system had a enough performances for the centerless grinding machine to machine the ferrule. -
To perform the finish outside-diameter grinding process of ferrules which are widely used as fiber optic connectors, a high-precision centerless grinding machine is necessary. In this study, the thermal characteristics of the high-precision centerless grinding machine such as the temperature distribution, temperature rise and thermal deformation, are estimated based on the virtual prototype of the grinding machine and the heat generation rates of heat sources related to the machine operation conditions. The reliability of the predicted results is demonstrated by the temperature characteristics measured from the physical prototype. Especially, the predicted and measured results show the fact that the high-precision centerless grinding machine consisted of the hydrostatic GW and RW spindle systems, hydrostatic RW feeding mechanism, RW swivel mechanism, on-machine GW and RW dressers, and concrete-filled steel bed, has very stable thermal characteristics.
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Fiber optic connector, ferrule, is a device to connect and align fiber optics cable on fiber-optic communication system. In this paper, Structural analysis was performed to analyze bed and frame structure of co-axial grinding machine. Deformation and modal analysis for natural frequency was performed using ANSYS Designspace program to analyze structural characteristics. New improved model of bed and frame structure was proposed based on initial basic model.
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In this study, tool path control algorithm for aspherical surface grinding was derived and discussed. The aspherical surface actually means contact points between lens and tool. Tool positions are generally defined at the center of a tool, so there is difference between tool path and lens surface. The path was obtained from contact angle and relative position from the contact point. The angle could be calculated after differentiating an aspheric equation and complex algebraic operations. The assumption of the control algorithm was that x moves by constant velocity while z velocity varies. X was normal to the radial direction of lens, but z was tangential. The z velocities and accelerations were determined from current error and next position in each step. In the experiment, accuracy of the control algorithm was checked on a micro-precision machine. The result showed that the control error tended to be diminished when the tool diameter increased, and the error was under sub-micro level.
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Recently, according to the development of semiconductor industry, needed to high-integration and high-functionality. These changes are required for silicon wafer of large scale diameter and precision of TTV (Total Thickness variation). So, in this research, suggest that the method of monitoring system is using motor current. This method is needed for observation of silicon wafer grinding process. Motor current sensor is consisted of hall sensor. Hall sensor is known to catching of change of current. Received original signal is converted to the diginal, then, it is calculated RMS values, and then, it is analysed in computer. Generally, the change of force is relative to the change of current, So this reason, in this research tried to monitoring of motor current change, and then, it will be applied to analysis for silicon wafer grinding process. using motor current sensor.
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In this study, rotary type diamond dressing system for ultra-precision centerless grinding for ferrule was developed at the first time and experiments were conducted with AE sensor and hall sensor system to verify the optimum dressing condition for ultra-precision centerless grinding for ferrule. The correlations with the condition of dressing are evaluated by AE signal analysis with root mean square (RMS) and frequency analysis. And current signals from hall sensor are also studied as a factor of dressing optimum condition selection. Dressing process was conducted to investigate the effects of depth of cut, rotating speed, and the number of overlap to select the optimum condition of rotary dressing system of ultra-precision centerless grinding machine for ferrule fabrication. In order to verify the optimum condition of dressing, AE and current signals were compared with the surface quality of dressing wheel and grinding wheel for ultra-precision ferrule grinding. All of these experiments were completed by Taguchi Methodology to reduce experimental time. Hence, the optimum condition of rotary dressing system for ultra-precision centerless grinding for ferrule fabrication can be selected following to the experiment result from signals of AE and hall sensor.
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An expert system is a system that employs human knowledge captured in a computer to solve problem that ordinarily require human expertise. Well-designed expert systems imitate the reasoning processes experts use to solve specific problem. Specially, expert systems are used to the engineer in manufacturing industry for the process control, production management and system management. In this paper, we propose the design process expert system for product design process in manufacturing industry and we present introduction and contents of design process expert system methodology and software for the air purifier design system. This system will be helpful to improvement of design process for the air purifier production.
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Data mining is the process of autonomously extracting useful information or knowledge from large data stores or sets. For analyzing data of manufacturing processes obtained from database using data mining, source data should be collected form production process and transformed to appropriate form. To extract those data from database, a computer program should be made for each database. This paper presents a program to extract easily data form database in industry. The advantage of this program is that user can extract data from all types of database and database table and interface with Teamcenter Manufacturing.
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We develop the evaluation method of functional requirements for excavator design. The functional requirement of the product can be deduced from voice of customer. QFD method is used in order to convert customer requirement to functional requirement. The measure of information index is used to evaluate quantitatively the product quality characteristics. The correlation score between customer requirements and functional requirements and benchmarking score of competitors are basic data for the measure of information.
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Despite all efforts, many product development projects fail and lead to an introduction of products that do not meet customers' expectations. In general, designers usually relies upon their past experiences of similar products as a source of design knowledge when they work on a new design project. Designers need a set of practical step-by-step tools and methods which ensure a understanding of customers' needs and requirements, as well as a past design experience knowledge. In this paper we propose a design initial value module for an excavator that proposes a key initial design parameter value in an early design stage to improve a design process on Customer Requirements. It makes possible to support designers more effectively, objectively, and easily. Also it can propose better products in terms of a customer satisfaction.
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Automotive pulleys play a key role in driving the cooling pump, oil pump, air-conditioner and so on by using an engine power. Researches on design processes and technologies of the pulleys can be found in many literatures. On the other hand, the areas related to manufacturing processes of the pulleys have been treated negligently. Vast data extracted from various information systems are transformed, integrated, and summarized to become a special database for helping users make a decision. The database, namely the data warehouse has been popularly used in the marketing and customer management of enterprises and recently applied to improve the design and manufacturing processes. In this study the manufacturing process of pulleys were analyzed through the intensive investigation of shop-floors and the interviews with workers and managers. The defects generated during a manufacturing process were categorized in a few types and the causes of defects examined for extracting the dominant parameters in the setup process for producing pulleys. As the first step to construct the data warehouse for the manufacturing processes of pulleys, authors proposed its architecture focused on the reduction of defect rate during the setup process.
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The Digital Meister is an advisory system to help the designer using the knowledge obtained from design and analysis data. In this paper, Taguchi method was applied to analyze the design parameters of automotive engine pulley. As a finite element method (FEM), ALGOR Multi-physics was used for analyzing the static analysis. As a result, two bending positions and material thickness were highly related to the maximum stress. These correlations between design parameters and analysis result will be used for supporting the design process of Digital Meister.
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Many data mining techniques have been proved useful in revealing important patterns from large data sets. Especially, data mining techniques play an important role in a customer data analysis in a financial industry and an electronic commerce. Also, there are many data mining related research papers in a semiconductor industry and an automotive industry. In addition, data mining techniques are applied to the bioinformatics area. To satisfy customers' various requirements, each industry should develop new processes with more accurate production criteria. Also, they spend more money to guarantee their products' quality. In this manner, we apply data mining techniques to the production-related data such as a test data, a field claim data, and POP (point of production) data in the automotive parts industry. Data collection and transformation techniques should be applied to enhance the analysis results. Also, we classify various types of manufacturing processes and proposed an analysis scheme according to the type of manufacturing process. As a result, we could find inter- or intra-process relationships and critical features to monitor the current status of the each process. Finally, it helps an industry to raise their profit and reduce their failure cost.
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In order to promptly cope with the various requirements of consumers, the environment of product development is being globalized in manufacturing industrials. For this reason, it is necessary to build up an efficient collaborative system for communication between remote area designers. Specially, while Internet and information technologies were merged with the manufacturing or business process, the research for collaborative system has become an important issue. Therefore, we propose a Web-based Engineering Collaboration Framework using SPS(SharePoint Portal Server) which is an enterprise business solution that integrates information from various system into one solution through single sign-on and enterprise application integration capabilities, with flexible deployment options and management tool. Through a Web-based Engineering Collaboration Framework, designers can exchange design information and have a conference in remote area designers or designer teams for alternative designs
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Real-time monitoring and controlling manufacturing process is important because of the unexpected events. When unexpected event like mechanical trouble occurs, prior plan becomes unacceptable and a new schedule must be generated though manufacturing schedule is already decided for order. Regenerating the whole schedule, however, spends much time and cost. Thus automated system which monitors and controls manufacturing process is required. In this paper, we present a system which uses radio-frequency identification and computer vision system. The system collect real-time information about manufacturing conditions and generates new schedule quickly with those information.
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컴퓨터 시뮬레이션이라는 개념이 세상에 소개되고 널리 사용된 것은 이미 오랜 전의 일이다. 또한 이러한 방법론이 여러 방면으로 제조/생산 분야 기업의 이윤을 증대시키는 데 기여할 수 있다고 알려져 있고 실제로 일부 영역에서는 기여를 하고 있다. 하지만, 냉정하게 현실을 판단해보면 컴퓨터 시뮬레이션이 좀 더 넓은 제조 영역에서 그 자체의 가치를 향상시키기 위해서는 아직 부족한 점이 존재한다. 예를 들어, 적용하고자 하는 분야에서 컴퓨터 시뮬레이션의 효용 가치를 발견하지 못한다거나, 시뮬레이션 모델링 업무 자체가 하나의 새로운 부담으로 다가오는 일, 또는 기업의 입장에서 시뮬레이션 소프트웨어의 가격이 너무 높기 때문에 컴퓨터 시뮬레이션을 도입하고 싶어도 비용적인 측면에서 벽에 부딪치는 일이 빈번하게 발생을 하고 있다. 본 논문에서는 이러한 문제점들을 해결할 수 있는 방법론들에 대한 분석 및 사례들을 보이고자 한다. 컴퓨터 시뮬레이션 모델링을 기존의 라이브러리를 활용하여 좀 더 쉬운 방법으로 재활용 할 수 있는 방법론, 제조 현장 어디서나 컴퓨터 시뮬레이터에 접속하여 시뮬레이션을 수행 할 수 있는 방법론 그리고, 이러한 방법론들이 실제로 기업의 업무에서 어떠한 기여를 할 수 있는지에 대한 분석을 수행하고자 한다.
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It is one of the most important things to determinate optimized cutting conditions which satisfy productivity and cost simultaneously in production and CAPP systems. These days many researchers have figured out the optimizing way for solutions of multi-object function to find the approach methods using algorithm such as genetic algorithm or tabu search, etc., instead of mathematical methods. The main creation of objective function is proposed by empirical method but which is difficult to set it up and to analysis. In this paper, an optimization method of cutting condition is shown using the ANN and GA for the multi-objective function in high speed machining.
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Tiny camera module using in modern cellular phone requires precise assembly processes. Higher camera resolution and more functions such as zoom lens make the number of camera parts bigger. As market grows rapidly, automatic assembly process is required. However, diverse product line and short life cycle make it difficult. To attack this, a flexible and expandable lens assembly system is proposed. For the fast manufacturing line formation, modular concept is adopted. Also each module is designed to have intelligence to save system formation time. The assembly system is built up on the standard flat-form which provides vibration free base, air and electric supply, controllers, etc. Futhermore, the assembly cell has the capability of handling tiny, thin, or transparent parts which are very difficult to align with vision.
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In this paper, a study on Web-based application using commercial CAE program, ANSYS is performed. Customized analysis, site or user oriented specific analysis, is suitable to user and user's demand who has little experience in structural analysis for specific CAE analysis. Customized analysis methodology using ANSYS Workbench SDK is presented through the web-based application. Case Studies of mobile phone about the implementation of web-based application are also presented as an example.
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Three dimensional shaded images are standard visualization method for CAD models on the computer screen. Therefore, much of the effort in the visualization of CAD models has been focused on how conveniently and realistically CAD models can be displayed on the screen. However, shaded 3D CAD data images captured from the screen may not be suitable for some application areas. Technical document, either in the paper or electronic form, can more clearly describe the shape and annotate parts of the model by using projected 2D line drawing format viewed from a user defined view direction. This paper describes an efficient method for generating such a 2D line drawing data in the vector format. The algorithm is composed of silhouette line detection, hidden line removal and cleaning processes.
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In collaborative environment, it is necessary that the participants in collaboration should share the same understanding about the semantics of terms. For example, they should know that 'Part' and 'Item' are different word-expressions for the same meaning. In this paper, we consider sharing between CAD and PDM data. In order to handle such problems in information sharing, an information system needs to automatically recognize that the terms have the same semantics. Serving this purpose, the semantic mapping logic and the ontology based mapper system is described in this paper. In the semantic mapping logic topic, we introduce our logic that consists of four modules: Character Matching, Instance Reasoning, definition comparing and Similarity Checking. In the ontology based mapper, we introduce the system architecture and the mapping procedure.
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There have been many studies to improve the performance of a database system focused on modifying data structure, data partitioning, and materializing strategy. The main contribution of this study is to propose a new alternative towards improving database performance by designing single table schema or processing queries virtually in main memory space. Material Requirement Planning(MRP) part explosion process has shown almost 2 times shorter under DB schema we suggested, and even more than 10 times shorter when separating and filtering policy of DB archiving process are assumed. Several experimental results are shown to illustrate the excellence of our solution.
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Over the past decade, changes in product development processes and increased consumer demands have dramatically influenced engineering working practices and targets. The information technology revolution has made its appearance concurrent to this relentless escalation in product engineering requirement. It has offered hopes for improved productivity despite these increasing demands. The wide availability of personal computing power, virtually inexhaustible sources of information and an abundance of computerized engineering tools have created great expectations. Knowledge information modeling system and database were developed using ASP and Microsoft SQL 2000 Server to share the DB that can be utilized to process on the web.
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Besides strong customer orientation, today's companies should respond increasingly to a market getting worse for securing competitiveness with a diversity of product spectrum. In these new conditions in the surrounding field of manufacturing, the changeability of manufacturing system develops more and more to the key success factor. The following contributions introduce a fast and cost-efficient concept for changeover which bases on a modular system's architecture. The modular structure of manufacturing system allows the required changing processes with limited side effects on other modules. Based on a modular concept, manufacturing systems can be easily configured and reconfigured to specific requirements.
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High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of parts created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool setting errors and surface roughness end tilted mills were used to cut aluminum samples. The results indicate that tool setting errors have significant effects on surface roughness and cutting forces.
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This paper presents a design experience of supervisory control system for agile and intelligent manufacturing(AIM). For effectively program job instructions, a Petri net-type graphical language is proposed and it can be applied to a various task such as concurrency and synchronization. PGL is consisted of PGL editor, PGL analyzer and PGL translator; PGL editor generates a job instruction program using graphic symbol. PGL analyzer prevents a deadlock or resource allocation of unit cell. PGL translator transfers to adequate sequential job commands of each unit cell.
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In this paper, a two-dimensional cross-channel model was applied to investigate influence of the gas diffusion layer(GDL) property and flow field geometry in the anode side for proton exchange membrane fuel cell(PEMFC). The GDL is made of a porous material such as carbon cloth, carbon paper, or metal wire mesh. To the simplicity, the GDL is represented as a block of material containing numerous pathways through which gaseous reactants and liquid water can pass. The purpose of present work was to study the effect of the GDL thickness and the porosity, and flow field geometry by computational fluid dynamics(CFD)
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Microsystems combine several microcomponents, optimized an entire system, to provide several specific technical functions by the shape of the microstructure. Microfabrication and micromachining techniques have played the key role in the fast development and commercialization of microsystems. Microreaction technology based on microsystems is a powerful tool for the evaluating new process and reaction pathways in chemical engineering. Because of the small characteristic dimensions of microreaction devices, mass and heat transfer processes are enhanced and, in addition, reaction conditions can be precisely controlled for optimizing yield and selectivity. The paper will report on the mixer design principle and explore several application fields of microreaction technology in the chemical synthesis
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In recent, LCD becomes one of the main display devices and expected to have quite good market share during the next couple of years. The demand for low cost and high performance, however, is becoming severe as the competition among other display devices like PDP, OLED increases. To satisfy this demand from market, we need to optimize the parts or modules of the LCD, reduce the number of the assemble and enhance the process for the high brightness and uniformity of the LCD. The LCD consists mainly of LCD panel and Backlight unit(BLU). BLU, which takes big portion of the cost for LCD, consists of light source, light guide panel and many kinds of functional film. Recently light guide panel or film for BLU has micro patterns on its surface and consequently to reduce the number of parts and enhace the brightness and its uniformity. In this study, some methodologies for the fabrication of the master/stamper and molding the light quide panel are introduced for 50um pitch of prizm patterned substrate. Mechanical machining process is adapted and optimized to fabricate micro patterned stamper using the micro cutting tool. Injection molding technology is also developed to obtain uniformly replicated micro patterned products.
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The technology trend of Flat Panel Display (FPD) equipments have been demanded that there are compact and multi-function. Therefore, nano/micro scale patterned on polymeric materials of Back Light Unit (BLU) in Liquid Crystal Display (LCD) that has been investigated. This paper describes a series of Horizontal Type Micro Tensile Tester that were carried out to investigate the load strain distance performance of typical polymeric material sheets. The polymeric materials film that micro size shaped specimens for tensile test are used by Cold-Isostatic-Press (CIP). Test equipment is Horizontal type Micro Tensile Tester that is presented to measure the micro scale mechanical property of thin film for FPD. This paper presents which easy testing tools measure for micro patterned on polyethylene (PET) specimens.
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We have designed micro-fuel processor system, which consists of a steam reforming area and a PROX(preferential oxidation) area. Micro-fuel processor system generates
$H_2$ rich gas from a methanol. In our experiment, we have integrated micro-fuel processor system using low temperature cofired ceramics (LTCC) process because LTCC is superior to other materials principally due to their high thermal and chemical stability, simpler fabrication processes, and lower materials cost. Therefore, we have studied and integrated micro-fuel processor system containing embedded heaters, cavities, and 3D structures of micro-channel with LTCC. Also we have optimized the LTCC process. -
Fabrication of MEA is important factor for proton exchange membrane fuel cell (PEMFC). MEA of PEMFC with hot pressing and direct coating method were prepared, and performances were evaluated and compared each other. The effect of MEA preparation methods, hot pressing methods and direct coating methods, on the cell performance was analyzed by impedance spectroscopy and SEM. The performance of PEMFC with direct coating method was better than with hot pressing method because membrane internal resistance and membrane-interfacial resistance were reduced by elimination of hot pressing process in MEA fabrication. In addition the micro structure of MEA with direct coating method reveals uniform interface between membrane and catalyst layer.
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We analyzed the thermal and mechanical behaviors of micro reformer for the purpose of design verifications and modification of micro channels. The reformer designed for hydrogen generation from methanol is essential to PEM(Proton Exchange Membrane) type fuel cell. For the mobile applications, the size and the simplicity would be the most critical issues. We utilized silicon process for micro reformer to obtain the thickness thinner than 2 mm thick. We have used commercial simulation software, IDEAS, to analyze the thermal and mechanical characteristics of micro reformer structure. The heat generation rates of heaters, heat transfer rates, and fluid temperatures are derived from thermal equilibrium relation and these values were used for thermal boundary conditions. We also analyzed the thermal stresses, thermal deformations to examine the possibility of failure.
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In order to implement nano-level accuracy of precision equipments, a nano control system is one of the key components. The control system consists of a controller, actuators and sensors having nano-level resolution. In this paper, application area and technical trend on the nano control system are introduced. Some required techniques for realizing nano-level resolution of a controller or actuator are presented. Technical innovation of a control system by IT-fusion and its effect are also described. Finally, domestic research activities for development of the IT-based nano control system are introduced.
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For agile production methods, manufacturing system requires development of a motion controller which has flexibility of general-purpose motion controller and productivity of specialized-purpose one. In this study we developed a flowchart programming development environment for motion language and process control. A controller designed on this environment can be used as a general purpose motion controller of a machine tool. Design of control programming based on a flowchart has the advantages such as reducing the programming time and improving intuitiveness of interface for users. We created the flowchart-based platform using OPC communication
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A Programmable Automation Controller (PAC) has been developed by Turbotek Co., Ltd. The developed system has multi-domain functionality-including sequence control, motion control and HMI- on a single platform. The PAC also has a common development platform for the design and integration of multi-domain automated systems. Since hardware of the developed system has modular architectures, performance and specification of the controller are determined by combination of specific modules. The developed system employs de facto standards such as OPC interface that allow users to easily exchange data as part of networked multi-vendor systems.
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The heat and vibration effect is known to cause a serious deformation in linear motor system. The paper presents a heat and vibration characteristics that compare a advanced linear motor with developed linear motor through experiment and analyses. The heat in linear motor system is identified for experimental data and analytic data using the Finite Volume Method (FVM). Also, it shows that the optimum standard analyzed the acceleration patterns of the moving part cause the vibration source in linear motor. It presents the analyzed dynamics of linear motor in compliance with a deformation of the non-linear factor.
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This paper describes the ultra precise position control of servo motor using sinusoidal encoder based on 'Arcsine Interpolation Method'. First, the paper theoretically analyzes and verify throughout experiments, the relationship between A/D converter input ripple and the total resolution to measure the precise position. Second, this paper presents a way to compensate the total gain and offset error by utilizing a low cost programmable differential amp, by which without any special expensive equipments they are easily on-line tuned and effectively compensated. Lastly, it was compared to servomotor position control characteristics using digital incremental 50,000ppr encoder. The test results show that, with much cheaper sinusoidal encoder, the proposed method exhibits better performance both in position control and ASD applications than the 50,000ppr optical encoder.
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This paper deals with the optimal design of a permanent magnet linear synchronous motor (PMLSM) with the analysis of prototype PMLSM. In the PMLSM, thrust ripple is one of the causes disturbing high-precision position control. Therefore, Response surface methodology (RSM), one of the optimization methods, is applied to obtain the shape decreasing thrust ripple of the prototype PMLSM. In the end, characteristic analysis of the PMLSM is performed by space harmonic method for shortening of a computation time, and final results is verified by finite element analysis.
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This article describes the development on a new style active hybrid bearing system including both merits of an aerostatic bearing system and a magnetic bearing system. The developed active hybrid bearing system has several advantages: exact rotation, robust controller against the variation of a disturbance, improvement of stiffness and a damper of the system at a high-speed operation, and constraints of the heat generated by a bias current. In order to measure a rotating error due to the change of a cutting force and the variation of a system parameter, a CCS (Cylindrical Capacity displacement Sensor) was used.
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This paper presents a novel cylindrical capacitive sensor (CCS) for both radial and axial motion measurements. Although the new CCS has almost the same geometric configuration as the conventional CCS, the unused axial area of the CCS is utilized to measure the axial motion of the rotor, which can affords more compact design and reduction of the system complexity. First, a theoretical model of the proposed CCS is derived. Based on the derived theoretical model, compensation methods to decouple the radial and axial motion measurements are proposed. In addition, error analysis is performed and a design rule is proposed to guarantee the same accuracy in measuring both radial and axial motions. Finally, a test rig and electronics for the proposed CCS are built and the effectiveness of the proposed CCS is verified with experiments and simulations.
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This study performed by a previous research for the applying expert system to active vibration control algorithm. In order to increase productivity and efficiency, high-speed rotating machines become popular these days. They are likely to vibrate and cause machine failure even though they have small unbalance. Therefore, a high-speed rotating machine needs a balancing technique. ISO 11342 classifies flexible rotors in accordance with their balancing requirements and establishes methods of assessment of residual unbalance. But, even if they finished balancing work, they have harmful effect vibration under the high-speed rotating environment. This vibration effect is very small, but it must be removed for the improvement of the rotor's spin accuracy. This paper introduces a new active control method that remove the exciting force by a phase control. For this method, the high-speed rotating rotor was reconstructed by a flexible rotor model. The forces which excite the rotating system suppose cyclic forces, we obtain the responses by numerical method. And then through the pattern analysis about the vibraton responses, the controler generate the control force with the reverse phase and similar magnitude. This paper suggest an phase control method and shows how to improve the rotating vibration accuracy of the flexible rotor dynamics system using phase control method.
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This paper proposes the direct detection method of phase angle for the power source, which is based on the PLL method. The proposed method using a bidirectional photo-coupler is used to directly detect the zero crossing of phase voltage and calculate the angular frequency in the controller based on a M/T algorithm. Through the method, the additional installation space in the traditional method using a potential transformer can be minimized and it can be easy to design. The paper presents straightforward schematic circuits, design and experimental results.
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Linear motor has been developed for linear motion of machine tools. Linear motor is useful to design the linear motion, high speed and high accuracy, because of the simple system not required the additional mechanical part such as coupling and ballscrew. This paper tested performance of linear motor such as velocity response, position tracing performance, subordinate Traction force change and positional accuracy.
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DTM (Diamond Turning Machine) is using for ultra precision manufacturing such as, plastic lens die or aspherical optics. This study is on a design of precision 2-axis stage for DTM. We designed and manufactured a back lash free stage using different weights and measured the positioning accuracy using Interferometer. Also, the 2-D moving accuracy is measured using the high magnification CCD technique. Then, the stage is tested with the machining of spherical and aspherical lens in a DTM with air bearing spindle. It was shown that the back lash free stage is effective for improving the positioning accuracy. Also, positioning control errors in motion control board were able to be found using the proposed stages system.
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Precision motor dynamometer is requiring for nano positioning control performance recently. Particularly, linear motor is using rapidly and the dynamometer needs is increasing. In this study, a precision control dynamometer is designed using MR (Magnetic Rheological) damper. The ultra precision motor system including the driver and controller is tested using the MR damper dynamometer. This dynamometer is able to measure torque for rotary motor or traction force with linear positioning accuracy for linear motor system.
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Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, an evaluation method for crashworthiness of Korean tilting train express is introduced. Crush characteristics for each part of tilting train express are evaluated numerically through 3-dimensional shell element analysis with LS-DYNA. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of tilting train express are evaluated numerically using full-rake collision simulations.
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TTX(Tilting Train eXpress) is being designed for improving the speed of conventional railway. The purpose of this study is to evaluate energy absorbing capacity and driver's survivability for a design candidate of the front end structure of TTX. A FE model with honeycomb block, under frame, and body frame is generated for crash simulation. Based on a level-crossing accident scenario, numerical simulation is performed using LS-DYNA. The results of crash analysis show that strength improvement of the current front end structure design candidate is needed to ensure driver safety.
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Crahworthy design of trains is now indispensable procedure in modern railway vehicle design for ensuring the safety of passengers and crew. It is now widely recognized that a more strategic approach is needed in order to absorb higher level energy in a controlled manner and minimize passenger injuries effectively. The first design step in this strategic approach is the design of the front end structure(so called HE extremities) to absorb a large part of total impact energy and then the structure of passengers non-accommodation zones(so called HE extremities) is designed to absorb the rest of impact energy. In this paper, the passengers entrance door area is selected as the LE(low energy) extremities and the design of the LEE was carried out. The main part of LEE design procedures is the design of energy absorbing tubes. For this purpose, the several tube candidates are introduced and compared to each others with numerical crash simulation.
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A lot of manufacturing knowledge and method have applied to increase manufacturing efficiency in industry field. DES(Discrete Event Simulation) is one of solution to deal with manufacturing problems in factory. Beginning of research, old maintenance system of KNR ( Korea National Railroad) and its technical problems are basically investigated. KNR has maintained railway vehicle with their own solution based on experience. Very advanced railway vehicles such as KTX (Korea Train Express) and TTX(Tilting Train Express) will be difficult to maintain with their old maintenance method. In order to apply knowledge of DES, maintenance field of railway must be considered. Imaginary maintenance machine are selected to variable of DES. Maintenance capability of each machine will be evaluated base on imaginary data from imaginary machine. The machine could be very expensive as well as difficult to replace. Target of research is minimization of number of machine in railway workshop. So basic knowledge of discrete event simulation is introduced. Then five essential stages of discrete event simulation are provided. Each maintenance case defined as event. Each event is discrete and simulated base on different case such as one maintenance line with one machine and one maintenance line with two machines in railway workshop. simple maintenance method, discrete event simulation, will be come out very powerful in complicate maintenance system and will be helpful to reduce maintenance cost as well as maintenance labor.
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The effect of residual stress on fatigue crack growth was investigated in terms of finite element analysis. Simulations were performed on a CT specimen in plane strain. An interface-cohesive element that accounts for damage accumulation due to fatigue along the notch direction has been used. Numerical results show that fatigue crack growth rate slows down when compressive residual stress field exists in front of the crack tip.
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High-speed trains with maximum speed of 300km/h, named KTX, have started revenue services since April 2004. Because of the geographical features of Korea a large portion of the 'Kyung-Bu' line is comprised of tunnels, which may cause excessive noise in a vehicle. The KTX interior noise follows in tunnel structure and the place where the quality appears different, the quality against hereupon from the commerce vehicle from the research which it sees it executes and comparison to analyze.
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KTX is the high speed train which is designed for 300km/h in maximum operation speed. But its long train set may cause unstable characters as swaying of the tail of a train and when the train is running on conventional line, its running safety is a point to be considered cautiously. In this study, we evaluated the running safety by the numerical analysis using VAMPIRE and compared the result with the test result of KHST, which is being in performance tests, for verifying the validity of analysis results
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Research purpose of this project is intending Maintenance Free of freight car and speed up of freight train. At goods transport as heightening traveling by ship speed of freight train shortening raise railway share of physical distribution and stand on tiptoe to Northeast Asia physical distribution main country to contribute expect. This paper is the performance elevation methods of next generation railway freight vehicles.
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This paper describes how to measure the running safety using vibration accelerometers theoretically, and considers the effect of vibration parameters, such as amplitude and period, on the running safety by numerical analysis, which shows that the running safety are decreased as those parameters are increased.
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Some bogie frames manufactured in 1999, 2000 year have the fatal problem. Three or four years later, the cracked end beam among them have discovered in 2002, 2003 year. The crack situation of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment. To improve the end beam, a research of covering the whole field of welded type bogie frame was started. Main line real tests were performed at Young-Dong line. The stress of main positions for bogie frame was measured. Also up-down direction and left-right direction vibration acceleration of the bogie frame were measured. At this time the tests were performed for the three types bogie. The test result concludes that the crack cause of the end beam is not brake load but vibration at running mainly. It is estimated that the life of the improved car which end beam reinforced is safe within the car permitted life(25 years). The improvement methods of the end beam are presented by construction modification, parts modification. The integrity evaluation is inspected by analysis the real line test results, the improvement methods of the end beam.
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The dynamic model was developed to analyze vibration acceleration and ride comfort during the operation of rubber-tired light rail vehicles. The ride comfort for standing passengers was analyzed in accordance with ISO 2631-1, UIC 513R, and CEN Draft prENV 12299 using this model. The result was applied to the detail design of Korean-standard, rubber-tired light rail vehicles, and the detail specifications related to ride comfort was determined based on this result. The ride comfort test was performed along the test track by using 2 car-train, and its result was compared with that of the ride comfort analysis, verifying the validity of the developed dynamic model. It was also verified whether or not the developed Korean-standardized, rubber-tired light rail vehicle met specified target specifications on ride comfort.
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To investigate the mechanism of ballast-flying phenomena by strong wind induced by high-speed trains, wind velocity in the vicinity of the track has been measured using 16-channel Kiel-probe array and detailed flow structure near the surface of the track has been analyzed. The position at which the underflow fully develop has been examined in order to assess the driving force of the turbulent flow under train and the results yields that the turbulent flow owing to the cavity of the inter-car as well as the friction force at the underbody of the train is the main reason of the strong wind under high-speed train. The preceding wind tunnel test results has been introduced to assess the probability of ballast-flying during the passage of the high-speed train by comparing the results from field-measuring. The results shows that when the G7 train as well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability for small ballast under 50g to fly is about 50% when it is on the tie. If the G7 train runs at 350km/h, the wind gust just above the tie increases to 30m/s, therefore more radical countermeasure seems to be needed.
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Automobile is in charge of most transportation system in modern urban city. However, in fact, cause of problem of road state, environment, and the other reasons, urban transit system is using as Mass Transit nowadays. Nevertheless Urban transit system is considering many kind of safety fact of that system which is increasing continuously nowadays, it occurs various train accident. This paper describes 3D Dimensional Measurement(EDM testing) and tensile testing results of carbody structure for crashed EMU(Electric Multiple Units). Tensile tests were performed on two different types of specimens in order to evaluate the strength changes before and after damages, obtained from plastic deformed area and nondeformed region of the crashed EMU. And Structural analysis of EMU was performed for the criteria of safety assessment. Structural analysis using commercial I-DEAS software provided important information on the stress distribution and load transfer mechanisms as well as the amount of damages during rolling stock crash. The testing results have been used to provide the critical information for the criteria of safety diagnosis.
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The opening of high speed railway upgraded our land transportation speed limit, causing lots of changes including living and culture and also paving the way for stepping up the railway technology. However, it is also true that we had a limit to adopt the existing railway system structured for 150km/h to the new structure requiring a higher speed of approximate 300km/h due to technological, based on the time and experience. More importantly, heading toward a step of operating such a high speed railway system, it has been practically and quickly proposed that the railway needs high speed railway engineering, maintenance technology of parts of the vehicles to have a stable maintenance foundation and localization of major parts. Therefore, this study was intended to research the actual displacement characteristics in runningg on an actual track for the purpose of developing the protective and maintenance technology of springs and dampers, which are core parts among suspension elements of a high speed railway vehicle. For this, it was researched the actual vehicle test and its interpretation centered on primary spring, which is used for the suspension system of a bogie, body-body dampers and body-bogie yaw damper. Also, to analyze the displacement characteristics of suspension system in the actual conditions of high speed railway vehicles, a vehicle‘s dynamic characteristics was analyzed and interpreted. At the same time, a tester for measuring the actual displacement of such suspension elements was designed and attached to actual vehicles, to measure the displacements that occur in running it on the Seoul-Busan line, one of major lines serviced by KTX. The displacement data gained from the test with actual vehicles was analyzed for its displacement distribution depending on the service sections and frequency, with which the valuable data necessary for any potential breakdown or maintenance in the future could be obtained.
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An integrated analytical model which should have essential dynamics on the longitudinal railway vehicle is developed. The model consists of translational movement, rotational movement, brake actuator, adhesion force between rail and wheel, and brake friction force between wheel and pad. Thus, during the deceleration for stopping, a feedback controller controlling the brake cylinder pressure is designed to improve ride quality and to release friction problems. Through the developed model, the feasibility of controlling the cylinder pressure is verified for the better performances during braking.
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Double-deck train have studied in the next generation train in KRRI. Double-deck train have more seat capacities compared with single deck vehicles and is a efficient, reliable and comfortable alternative train. Because of heavy weight, weight minimization of double-deck train carbody is imperative to reduce cost and extend life-time of train. Weight minimization problem of the double-deck train car-body is required to decide 66 design variables of thicknesses for large aluminum extruded panel while satisfying stress constraints. Design variables are too many and one execution of structural analysis of double-deck train carbody is time-consuming. Therefore, we adopt approximation technique to save computational cost of optimization process. Metamodels such as response surface model (RSM) and kriging model are used to approximate model-based optimization is described. RSM is easy to obtain and expressed explicit function, but this is not suitable for highly nonlinear and large scaled problems. Kriging model employs an interpolation scheme and is developed in the fields of spatial statistics and geostatistics. Target of this design is to find optimum thickness of AEP to minimize weight of doulbe-deck train carbody. In this study, meta model techniques are introduced to carry out weight minimization of a double-deck train car-body.
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Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result. This study is designed to analyze the air pressure control about braking force in rolling stock, also, by comparing braking force of high speed railway with that of high speed train. This paper suggests to establish a method of computation of braking force form the air pressure control. And The high speed train researches into patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.
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This study investigates the change of the temperature and mechanical properties of the braking disk for the railway vehicle. The average temperature is measured about
$100^{\circ}C$ and the maximum temperature is measured over$200^{\circ}C$ by non-contact sensor from Seoul to Chun-an. In the$20^{\circ}C-300^{\circ}C$ , the 0.2% offset yield strengths of the disk (GC25-30 material) are a little down to the reference value, but the linear relation of tensile test result is not find from the linear change of temperature. However, JIC values have the inverse proportion to the temperature, and the JIC value at$200^{\circ}C$ decrease 30.55% from the JIC. value of the room temperature. This result means that the crack length on the braking disk is rapidly increase at$200^{\circ}C$ . -
This paper describes the result of structure analysis and load test for bogie frame. The purpose of the analysis and test is to evaluate an safety which body structure shall be considered fully sufficient rigidity so as to satisfy proper system function under maximum load. Bogie system consists of bogie frame, suspensions, wheel-sets, braking system and transmission system. Among these component, the bogie frame is most significant component subjected to the vehicle and passenger loads. The evaluation method is used the JIS E 4207 specification throughout the FEM analysis and static load test. The analysis and test results have been very safety and stable for design load conditions.
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There are technical requirements to manufacture large size functional parts with not only simple geometries like a flat or spherical surface but also sculptured geometries. In addition, the required machining accuracy for these parts is becoming more severe day-by-day. In general, the forms of machined parts are determined by relative position between the workpiece and the tool during cutting. To improve machining accuracy, the relative position error should be maintained within the required accuracy. This study deals with estimation and calibration of depth of cut using AE signal in micro-machining.
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Single point diamond turning technique for optical crystals is studied in this paper. The main factors which are influential the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability. The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. The purpose of our research is to find the optimal machining conditions for ductile cutting of optical crystals and to apply the SPDT technique to the manufacturing of ultra precision optical components of brittle material(Ge). Many technical challenges are being tried for the large space infrared telescope, which is one of the major objectives of the National Strategic Technology Road Map (NSTRM).
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The objective of this research work is to investigate the effects of process parameters, such as power of laser, travel speed of laser and material thickness, on kerfwidth and characteristics of the cut surface for the case of cutting of CSP 1N sheet using high power continuous wave Nd:YAG laser. In order to find relationship between the process parameters on the quality of the cut section, such as kerfwidth, surface roughness and the striation formation, several laser cutting experiments are carried out. From the results of experiments, an optimal cutting speed for each cutting condition has been obtained to improve the quality of the cut surface.
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This study predicts the heat-affected zone (HAZ) after electrical discharge machining. To predict HAZ, the temperature distribution is calculated using FEM. Heat flux is calculated from electrical energy, and it can be assumed Gaussian distribution. Plasma channel expands as time goes. Copper and NAK80 are used as the workpiece material. The depth of HAZ in simulation is determined by temperature distribution. The simulation results were compared with a developed actual single discharge crater. Through investigating the cross section of simulated & actual craters, the depth of HAZ in simulation and experiment are compared. Simulation model can predict the crater shape.
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In this study, the formed tool is used to machine of bearing raceway and a shape compensation scheme is proposed to compensate for shape of it in turning process. It is introduced the conventional design method of the formed tool; a simple depth compensation method and a drawing compensation method. And it is performed to investigate in detail properties of the formed tool about a tool angle and problems of a turning process of bearing raceway using the formed tool. The applicability of the proposed scheme is examined by comparing the experimental results obtained by a new designed formed tool with those obtained by a conventional tool.
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Laser bonding between similar and dissimilar thermoplastics has been investigated by making use of laser transmission weld technique. Spot welding of two layers of plastic materials has been demonstrated by using of a high-quality diode-laser with 808nm wavelength. Weld areas increases according to power density, exposure time. The results of peel out test show that peel strengths increase with the area of molten plastics. Layers, which have the same chemical properties, have good bonding qualities. A bonding method which dye film is coated on the interface is used for laser bonding between plastics with high transmission for laser wavelength. Laser transmission bonding is worthy of attention because it is not in contact, requires a few tooling devices, allows a flexible energy delivery and produces nearly invisible welds
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Chemical Mechanical Polishing (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. In general, CMP is a surface planarization method in which a silicon wafer is rotated against a polishing pad in the presence of slurry under pressure. The polishing pad, generally a polyurethane-based material, consists of polymeric foam cell walls, which aid in removal of the reaction products at the wafer interface. It has been found that the material removal rate of any polishing pad decreases due to the so-called 'pad glazing' after several wafer lots have been processed. Therefore, the pad restoration and conditioning has become essential in CMP processes to keep the urethane polishing pad at the proper friction coefficient and to allow effective slurry transport to the wafer surface. Diamond pad conditioner employs a single layer of brazed bonded diamond crystals. Due to the corrosive nature of the polishing slurry required in low pH metal CMP such as copper, it is essential to minimize the possibility of chemical interaction between very low pH slurry (pH <2) and the bond alloy. In this paper, we report an exceptional protective coated conditioner for in-situ pad conditioning in low pH Cu CMP process. The protective Cr-coated conditioner has been tested in slurry with pH levels as low as 1.5 without bond degradation.
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Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO2 lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of martensitic structure. In this investigation, the microstructure features occurring in Nd:YAG laser hardening SM45C steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimism of the processing parameters for maximum hardened depth of SM45C steel specimens of 3mm thickness by using CW Nd:YAG laser. Travel speed was varied from 0.6m/min to 1.0m/min. The maximum hardness and case depth fo SM45C steel are 780Hv and 0.4mm by laser hardening.
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This paper is described about the technique of ultra-precision machining for a infrared camera aspheric mirror. A 200 mm diameter aspheric mirror was fabricated by SPDTM. Aluminum alloy as mirror substrates is known to be easily machined, but not polishable due to its ductility. Aspheric large reflector without a polishing process, the surface roughness of 5 nm Ra, and the form error of
$\lambda/2\;(\lambda=632.8 nm)$ for reference curved surface 200 mm has been required. The purpose of this research is to find the optimum machining conditions for cutting reflector using A16061-T651 and apply the SPDTM technique to the manufacturing of ultra precision optical components of Al-alloy aspheric reflector. -
An aspheric mirror, which requires less than
$\lambda/2\;(\lambda=632.8nm)$ of form error for the$\phi$ 200mm reference curved surface, has been manufactured with an ultra-precision turning machine. We have known through several tests that the deformation patterns of the reflecting surface is related with bolting positions. In this paper the effect of main factors on deformation of a reflector is studied with a FE code. The considered factors are angular velocity, natural frequencies for a mirror, temperature increment during machining. The obtained test results are similar to the deformation shape due to the assumed temperature increment. -
The cutting characteristics of hardened steel by a PCBN tool is investigated with respect to workpiece surface roughness, cutting force and tool flank wear of the vision system. Backpropagation neural networks (BPNs) were used for detection of tool wear. The neural network consisted of three layers: input, hidden and output. The input vectors comprised of spindle rotational speed, feed rates, vision flank wear, and thrust force signals. The output was the tool wear state which was either usable or failure. Hard turning experiments with various spindle rotational speed and feed rates were carried out. The learning process was performed effectively by utilizing backpropagation. The detection of the abnormal states using BPNs achieved 96.4% reliability even when the spindle rotational speed and feedrate were changed.
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The setting of a presintering temperature is carried out on the basis of the Vickers hardness of the presintered compact in the method for producing a ceramic sintered compact comprising presintering a formed compact composed of a ceramic powder and a sintering assistant, then machining the presintering compact and subsequently sintering the machined compact. The Presintering temperature is preferably set at a temperature so as to provide 213-230 Hv Vickers hardness of the compact for presintering. Furthermore, the presintering temperature is preferably within the range of 1,300-1,450
$^{\circ}C$ . -
Gear is an important machine element to be used transmission in case short between axis. We drew gear using automatic design program to solve problem when it draw gear. We manufactured gears that it have different pressure angles using W-EDM. And we got a 2D profile of manufactured gear using reverse engineering. So we got to manufacturing error in comparison with CAD data and measured data. In result we could manufacture precise gear through improvement of manufacturing processes.
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Among several polishing techniques for micro structures, polishing process using magnetorheological(MR) fluid has advantages in the finishing process of 3-D micro structures because abrasives in the fluid can reach surfaces with complex feature and play their role. Although many researchers have been trying to reveal its polishing mechanism of the MR polishing, it has not been successful because in-situ measurement of state variables is difficult and process parameters are complex. In fact, one of the key factors for applying process control methodologies, such as Run-to-Run control, is the measuring and monitoring of slurry quality because the process strongly depends on the fluid property. Therefore, it is necessary to maintain consistent slurry quality to guarantee the process repeatability. The proposed equipment achieves the longer life cycle of MR fluid and reduces the variability of products. A new method to measure the material removal rate in MRF polishing process is also proposed and discussed.
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This paper is to investigate the influence of the endface quality on the loss characteristics of a plastic optical fiber connector for in-car network service. Using the parameters of the surface roughness and applied load, insertion loss of connector is measured. Due to scattering and change of refractive index, an optimal condition for low-loss coupling exists. We present the optimal condition as surface roughness
$R_{rms}$ = 8 nm and contact load up to 50 N. -
Mobility of tracked vehicles is dependent on performance of its power equipment and suspension systems. Especially, its road wheels, components of its suspension systems, play an important role in distributing the vehicle weight on the ground and preventing from misguiding tracks. In this study, the maximum force acted on multipurpose tracked vehicles driven on the worst condition was calculated. And then FE analyses were carried out to evaluate the strength of the road wheels under the maximum force condition. For quality evaluation of the road wheels, FE simulations and experimental works were carried out under specific slant loads. Residual deformation for the slant loads was investigated and commented upon.
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In this paper, the concept of sustainability was applied to mechanical design and manufacturing of mobile-phone case. A new evaluation method to find products' good and weak point for sustainability was developed. Two mobile phones were evaluated using the evaluation tool. As a result, electro-magnetic (EM) wave was considered as a harmful factor of the products, and improved front panel was made using nano particles that absorb EM waves. The EM shielding tests revealed that silver nano powders absorbed EM while MWCNT had no effect.
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The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its time effectiveness. However, it's well known that the membrane analysis can not provide correct information for the processes which have considerable bending effects. In this research it tried to compare the analysis results which use the shell element which is applied newly in the AutoForm commercial software with actual experimental results. The shell element is compromise element between continuum element and membrane element. The Finite element method by using shell element is the most efficient numerical method. From this research, it is known that FEA by using shell element can predict accurately the problems happened in actual experimental auto-body panel.
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Most metals are polycrystalline material whose deformation is dominated by the slip system. During the deformation process, orientation of slip systems is rearranged with preferred orientations, leading to deformation-induced crystallographic texture which is called deformation texture. Depending on the texture development, the property of material can be changed. The rate-independent crystal plasticity which is based on the Schmid law as a yield function causes a non-uniqueness in the choice of active slip systems. In this work, to avoid the slip system ambiguity problem, rate-independent crystal plasticity model based on the smooth yield surface with rounded-off corners is adopted. In order to simulate the polycrystalline material under plastic deformation, we employ the Taylor model of polycrystal behavior that all the grains are assumed to be subjected to the macroscopic velocity gradient. Rigid-plastic finite element program based on this rate-independent crystal plasticity is developed to predict the grain-level deformation behavior of FCC metals during metal forming processes. In the finite element calculation, one integration point is considered as a crystalline aggregate which has a number of crystals. Macroscopic behavior of material can be deduced from the behavior of aggregates. As applications, the extrusion processes are simulated and the changes of mechanical properties are predicted.
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TFT-LCD(Thin Film Transistor Liquid Crystal Display) module is representative commercial product of FPD(Flat Panel Display). Thickness of TFT-LCD module is very thin. It is adopted for major display unit for IT devices such as Cellular Phone, Camcorder, Digital camera and etc. Due to the harsh user environment of mobile IT devices, it requires complicated structure and tight assembly. And user requirements for the mechanical functionalities of TFT-LCD module become more strict. However, TFT-LCD module is normally weak to high level transient mechanical shock. Since it uses thin crystallized panel. Therefore, anti-shock performance is classified as one of the most important design specifications. Traditionally, the product reliability against mechanical shock is confirmed by empirical method in the design-prototype-drop/impact testredesign paradigm. The method is time-consuming and expensive process. It lacks scientific insight and quantitative evaluation. In this article, a systematic design evaluation of TFT-LCD module for mobile IT devices is presented with combinations of FEA and testing to support the optimal shock proof display design procedure.
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In order to design the aspherical lens, the revisions and the steps of the mathematical method are influenced with a lot of variables. The accuracy of the aspherical lens can be changed by these variables. Besides, to design the aspherical lens, many mathematical functions should be used. To use these mathematical functions is protected by patent administration. Therefore it is very difficult for most of developed countries to use them. This fact has been interrupting not only the development of the technique of a design of the aspherical lens but also the development of the equipments of optics. Because approximate values are used in most of common programs which create the aspherical lens : basically these common programs have variations. Therefore these aspherical lens are not accurate. In the paper, we calculated accurate values by using the refractive index of lens. Based on these data, wee created self-operating design programs. Consequently, our lens is more accurate than the aspherical lens which is created by the common programs influenced with approximate values. The used programs belonging to AutoCAD is Visual LISP.
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A process map has been developed, which can identify the process conditions for weak mechanical bonding at the contact surface during the direct extrusion of a Cu-Ti bimetal bar. Bonding mechanism between Cu and Ti was assumed as a cold pressure welding. Then, the plastic deformation at the contact zone causes mechanical bonding and a new bonding criterion for pressure welding was developed as a function of the principal stretch ratio and normal pressure at the contact surface by analyzing micro local extrusion at the contact zone. Finite element analyses for extrusion of Cu-Ti bimetal bars were performed for various process conditions. The deformation history at the contact surface was traced and the proposed new bonding criterion was applied to predict whether the mechanical bonding at the Cu-Ti contact surface happens. Finally, a process map for the extrusion of Cu-Ti bimetal bar is suggested.
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In this study, optimization design technique for control of solid-fluid coupled force (sloshing) using evolutionary method is suggested. Artificial neural networks(ANN) and genetic algorithm(GA) is employed as evolutionary optimization method. The ANN is used to analysis of the sloshing and the genetic algorithm is adopted as an optimization algorithm. In the creation of ANN learning data, the design of experiments is adopted to higher performance of the ANN learning using minimum learning data and ALE(Arbitrary Lagrangian Eulerian) numerical method is used to obtain the sloshing analysis results. The proposed optimization technique is applied to the minimization of sloshing of the water in the tank lorry with baffles under 2 second lane change.
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Brake judder, which occurs when brakes are suddenly applied to a vehicle driving at high speed, affects the driver's safety to a great extent. It also has a low frequency that drivers can easily feel. Among theses presented, none offered studies using modeling of actual brakes in computer simulation in order to recreate the brake judder phenomenon, and most of them directly applied the frequency generated by the judder. To resolve this issue, this study hopes to develop a computer model that can recreate the phenomenon of brake judder. In this paper, in order to examine the vibration problem occurring when brake is applied on the test car, the multibody dynamic analysis program ADAMS was used to develop a computer model that can recreate the actual braking mechanism while breaking away from the existing understanding of brakes. Thus the existence of the brake judder phenomenon due to DTV(Dist Thickness Variation) and wheel rotating speed was examined through the developed model.
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This paper propose an advanced control strategy to improve vehicle handling and directional stability by integrating Active Front Steering(AFS) with Electronic Stability Program(ESP) . The effect of the integrated control system on the vehicle handling characteristics and directional stability is studied through a close loop computer simulation of and eight degree of freedom nonlinear vehicle model and driver model. Simulation results confirm the effectiveness of the proposed control system and the overall improvements in vehicle handling and directional stability
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현재 정밀한 길이를 측정하기 위해서는 광 간섭계를 이용한 측정기술이 주로 사용되어지고 있다. 이러한 광 간섭계의 발전과 더불어 이보다 더 높은 분해능을 얻기 위해 광파장보다 1000배 정도 짧은 엑스선을 이용한 변위 측정 기술개발이 진행되고 있다. 본 연구에서는 이러한 엑스선을 이용한 간섭계를 제작하고, 광 간섭계와 결합된 광/엑스선 복합간섭계를 구성하여 광 간섭계가 안고 있는 자체의 비선형성이 제거된 정밀 변위 측정 시스템을 구성하였다. 그 응용으로써, 제작된 광/엑스선 복합간섭계를 이용하여 나노미터 영역에 서 사용하는 transducer의 비선형성을 측정하였다.
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Decentralized Dynamic Surface Control(DDSC) for a class of nonlinear system interconnected via sensor network is presented in this paper. While a centralized design approach of DSC was developed in [1], the decentralized approach to deal with complex large-scale systems is proposed under the assumption that interconnected functions among subsystems are known via sensor network. As shown in [2], the separation principle for DDSC will allow us to design an estimation filter independently. Furthermore, the theoretical results are used to design and simulate an active vibration isolator under the assumption that many embedded sensors are distributed and communicate each other via wireless communication.
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This paper addresses sliding mode control (SMC) of the anti-lock braking system (ABS) with a compensator of model uncertainties such as vehicle parameter variation, unmodeled dynamics, and external disturbances. A sliding mode controller (SMC) is designed with a nominal vehicle model to achieve a desired wheel slip ratio. A disturbance observer (DOB) is introduced to compensate the model uncertainties and is designed with a transfer function of a hydraulic brake dynamics. Through simulations on the model uncertainties, it is verified that the sliding mode control with the DOB can give the simulation results better than the sliding mode control without the DOB.
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The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that cost less and are faster than previous semiconductor processes have been developed for the production of electric paper and RFID. The system proposed in this study prints by spraying the molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage, As an operating system, the piezoelectric(PZT) method has very valuable uses. However, the PZT actuator has a very big hysteresis characteristic due to the ferroelectric characteristics of the PZT element. This causes problems in the system position control characteristics and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. The study proposed a inverse hysteresis model, a mathematic modeling method that can express the geometric relationship between voltage and displacement, in order to reduce the hysteresis of the PZT actuator. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good precision position control performance.
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The attitude control, sensors and camera installed on the spacecraft should be located according to the system alignment requirement. The alignment measurement requirement accuracy for the sensors should be below
$\pm$0.1 . Therefore, Alignment Measurement System which is combined theodolite, Rotating table and digital inclinometer etc., should be used. As the measurement accuracy is required very precise, the appropriate measurement procedure and alignment angle measurement, calculation and shimming work should is accomplished. Consequently, this paper is accomplished the works to align the measurement requirement accuracy throughout alignment measurement and shimming work of installed module and sensor -
Tracking control of an automatic pipe cutting robot (APCROMB) is studied. Using magnetic force APCROMB, which is designed and developed in Kyung Hee University, binds itself to the pipe and executes unmanned cutting process. The gravity effect on the movement of APCROMB varies as it rotates around the cylindrical pipe laid in the gravitational field. To maintain a constant velocity and consistent cutting performance against the varying gravitational effect, the authors adopt a multi-rate repetitive learning controller (MRLC), which learns the required effort to cancel the repetitive tracking errors caused by nonlinear effect. In addition to the varying gravity effect other types of nonlinear disturbances including backlash in the driving system and the slip between the wheels of APCROMB and the pipe also cause degradation in the cutting process. In order to identify those nonlinear disturbances the position estimation based on the encoder attached at the motor is not good enough. To identify the absolute angular position of APCROMB the authors propose the angular position estimation based on the signals from a MEMS-type two-axis accelerometer mounted on APCROMB. The tracking performances of APCROMB with a MRLC using the encoder-based position estimation is experimentally measured and results are shown. Also the difference between the encoder-based angular displacement measurement and the accelerometerbased angular displacement measurement is included.
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Gauge blocks are the most widely used material measure in length field in industry. The gauge block interferometer, which is the gauge block measuring system, comprises Twyman-Green type interferometer optics and light sources having precisely known wavelengths. This paper describes the work done for advancing the measurement system and automating the measurement process. The advancing of the system was done mainly by exchanging the spectral lamp with the frequency stabilized lasers, and the automation of measurement was achieved by modifying the hardware and developing the automatic measuring software. As the results of this work, the contrast of interferometric fringes of gauge blocks longer than 100 mm s enhanced about 20 times, and the measurement time has reduced down to 50% by automation.
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This paper presents the temperature-pressure characteristics of SMH actuator using a peltier module. The simple SMH actuator, consisting of the plated hydrogen-absorbing alloy as a power source, Peltier elements as a heat source and a cylinder with metal bellows a functioning part has been developed. The SMH actuator is characterized by its small size, low weight, noiseless operation and a compliance similar to that of the human body. A new special metal hydride(SMH) actuator that uses the reversible reaction between the heat energy and mechanical energy of a hydrogen absorbing ally. It is well known that hydrogen-absorbing alloys can reversibly absorb and desorb a large amount of hydrogen, more than about 1000 times as their own volume. To improve the thermal conductivity of the hydrogen-absorbing alloy, an electro-less copper plating has been carried out. The effects of the electro-less copper plating and the dynamic characteristics of the SMH actuator have been studied. The hydrogen equilibrium pressure increases and hydrogen is desorbed by heating the hydrogen-absorbing alloys, whereas by cooling the alloys, the hydrogen equilibrium pressure decreases and hydrogen is absorbed. Therefor, the SMH actuator has the characteristic of being light and easy to use and so is suitable for use in medical and rehabilitation applications.
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The measurement method by Laser Speckle Interferometry which uses the interference law which will grow precedes and with it explains a resolution measurement ability and together the change of place arrowhead and general measurement, at real-time measurement sensitivity it has application boat song from candle precise measurement field it is increasing. But, currently the domestic application technique to sleeps and optical science military merit by optical science interferometer and directness it composes purchases to the level which it applies the expensive commercial business equipment the outside and in spite of the technical ripple effect is deficient even in many strong point. The hazard which complements like this problem point form technical development it leads from the research which it sees and an application degree and to sleep as the measurement equipment which tries to develop the small-sized optical science interference sensor and an interpretation program it raises it does.
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The quality of a rotating body such as a washing machine depends on the vibration characteristics. So, the researches to reduce the vibration of a washing machine are actively performing, but it is very difficult to conduct these experiments because there are many design parameters affecting the vibration behavior. Accordingly, in this study it was complete to build a modeling of a drum washing mashing to analyze and predict vibration behaviors. The design parameters which affect the vibration were found, and the method for the systematic analysis of the design parameters was suggested using axiomatic design. In the previous study, the effect of the gasket has not considered on vibration behaviors, but in this study it was considered. The simulation results showed good agreements with the experimental results in the vibration displacement and the vibration tendency of a drum washing machine.
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We describe a new scheme of dispersive white-light interferometer that is capable of measuring the thickness profile of thin-film layers, for which not only the top surface height profile but also the film thickness of the target surface should be measured at the same time. The interferometer is found useful particularly for in-situ inspection of micro-engineered surfaces such as liquid crystal displays, which requires for high-speed implementation of 3-D surface metrology.
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Technological feasibility of using recently-available femtosecond ultra short pulse lasers for advanced precision length metrology is investigated with emphasis on absolute distance measurements with
$10{\mu}m$ ??resolution over extensive ranges. The idea of using femtosecond lasers for the measurement of absolute distances is based on the fact that a short pulse train is a mode-locked combination of discrete monochromatic light components spanning a wide spectral bandwidth. The synthetic wavelength is created from the repetition frequency,$f_r$ of the femtosecond laser and for more precise resolution, higher-order harmonics of the repetition frequency may be selected as the synthetic wavelength by using appropriate electronic filters. -
A compact linear and angular displacement measurement device was developed by combining a Michelson interferometer and an autocollimator to characterize the movement of a precision stage. A Michelson interferometer and an autocollimator are typical devices for measuring linear and angular displacement, respectively. By controlling the polarization of reflected beam from the target mirror of the interferometer, some part of light was retro-reflected to the light source and the reflected beam was used for angle measurement. The interferometer and the autocollimator use the same optic axis and the target mirror can be easily and precisely aligned orthogonal to the optic axis by monitoring the autocollimator s signal. The autocollimator was designed for angular resolution of 0.1 arcsec and dynamic range of 60 arcsec. The nonlinearity error of interferometer was minimized by trimming the gain and offset of the photodiode signals. Through the experiments, we evaluate the performance of measurement device and discuss its applications.
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Surface quality of a micro-processed sample with laser has been investigated by using of scanning confocal microscope(SCM) and atomic force microscope(AFM). Samples are bump electrodes and ITO glass of LCD module used in a mobile phone and a wafer surface scribed by UV laser. A image of
$140\times120{\mu}m^2$ is obtained within 1 second by SCM because scan speed of a x-axis and y-axis are 1kHz and 1Hz, respectively. AFM is able to measure correctly hight and width of ITO and scribing depth and width of a wafer with a resolution less than 300 . However, the scan speed is slow and it is difficult to distinguish a surface composed of different nm kinds of materials. Results show that SCM is preferable to obtain a image of a sample composed of different kinds of material than AFM because the intensity of a reflected light from surface is different from each material. -
A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.
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Many process parameters have an effect on the auto-body panel forming process. A well designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented, in this paper The one-step approach using a finite element inverse method will be introduced to predict the optimal forming with changing of blank pressure the developed program is applied to auto-body panel forming.
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Molding shrinkage s variation is one of the problems to be solved in conventional injection molding. Despite many trying-out has been to solve these, intrinsic causes of shrinkage such as orientation and thermal exchange between melt and mold has yet not solved. For reducing shrinkage and residual stress on molding, injection compression molding process was invented. In this study, experiments about effect of injection compression molding's parameters on shrinkage of molding were conducted with PMMA and compared with conventional injection molding's shrinkage. Before the injection compression molding experiment, molding shrinkage rate was predicted by analyzing pvT graph and was compared with the results of experiment. The shrinkage rate of injection compression molding was lower than convention injection molding' one but was different from the predicted shrinkage. The reason was observed that experiment mold as not positive type, flowing backward of melt into nozzle and unreasonable mechanism of injection molding machine.
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It is generally accepted that fracture toughness of fiber-reinforced polymer composites is affected by loading rate in an atmospheric presure condition. For a present study, the loading rate effect on the fracture toughness of fiber-reinforced laminated composites in the hydrostatic pressure condition was investigated. For this purpose, fracture tests have been conducted using carbon/epoxy composites applying three steps of the strain rate at 270 MPa hydrostatic pressure condition. The loading rates applied were 0.05%/sec, 0.25%/sec, and 0.55%/sec. Fracture toughness was determined from the work factor approach as a function of applied loading rate. The result showed that fracture toughness decreased as the loading rate increased. Specifically, the fracture toughness decreased 12% as the loading rate increased from 0.05%/sec to 0.55%/sec.
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Plastic parts are molded for the purpose of mass production in multi-cavity system. Therefore, designer is usually designing molds that has geometrically balanced runner lay-out for filling balance at each cavities. Although, mold is manufactured with geometrically balanced runner lay-out, there are actually filling imbalances in cavities. These filling imbalances phenomenon are caused by complicated interaction between melt and mold. In this study, based on previous studies for filling imbalances in cold-runner mold, filling imbalances in hot-runner mold were investigated by CAE and injection molding experiments. ABS, PMMA as amorphous polymer and PA, PP as crystalline polymer were used to compare the filling imbalances. The filling imbalances decreased as injection rate increased without regard to kind of resins and were lower than the one of cold-runner.
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A systematic procedure of probability analysis for general distributions is developed based on the first four moments estimated from polynomial interpolation of the system response function and the Pearson system. The function approximation is based on a specially selected experimental region for accuracy and the number of function evaluations is taken equal to that of the unknown coefficient for efficiency. For this purpose, three error-minimizing conditions are proposed and corresponding canonical experimental regions are formed for popular probability. This approach is applied to study the stochastic properties of the performance functions of a MEMS structure, which has quite large fabrication errors compared to other structures. Especially, the vibratory micro-gyroscope is studied using the statistical moments and probability density function (PDF) of the performance function to be the difference between resonant frequencies corresponding to sensing and driving mode. The results show that it is very sensitive to the fabrication errors and that the types of PDF of each variable also affect the stochastic properties of the performance function although they have same the mean and variance.
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A remeshing algorithm using tetrahedral elements has been developed, which is adapted to the mesh density map constructed by a posteriori error estimation. In the finite element analyses of metal forging processes, numerical error increases as deformation proceeds due to severe distortion of elements. In order to reduce the numerical error, the desired mesh sizes in each region of the workpiece are calculated by a posteriori error estimation and the density map is constructed. Piecewise density functions are then constructed with the radial basis function in order to interpolate the discrete data of the density map. The sample mesh is constructed based on the point insertion technique which is adapted to the density function and the mesh size is controlled by moving and deleting nodes to obtain optimal distribution according to the mesh density function and the quality optimization function as well. After finishing the redistribution process of nodes, a tetrahedral mesh is constructed with the redistributed nodes, which is adapted to the density map and resulting in good mesh quality. A goodness and adaptability of the constructed mesh is verified with a testing measure. The proposed remeshing technique is applied to the finite element analyses of forging processes.
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It is well known that tire tread pattern has much influence on the tire pattern noise. The paper describes the method of pattern noise reduction by using the pitch sequence, both on the smooth asphalt roads and on the trenched concrete roads. The noise of tire is classified as either airborne or structure borne noise. Pattern noise through the airborne is considered as a major noise source at high speeds. As block impacting and air pumping by tread patterns are major noise source, tire pattern noise can be greatly influenced by optimal pitch sequence. The goal of this paper is to provide tire engineers with pitch sequence to reduce pattern noise effectively.
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All over the world, many kinds of micro-actuators were already developed for various applications. The actuators are using various principles such as electromagnetic, piezoelectric and thermopneumatic etc. The most of the micro-actuators have been made using 2D based MEMS technology. In these actuators, it is difficult to drive 3-dimensional motion. This characteristic gives the limit of actuator application. However, micro-stereolithography technology has made it possible to fabricate freeform three-dimensional microstructures. In this technology, 2-dimensional micro-shape layer is cumulated on the other layers. This layer-by-layer process is the main principle to fabricate 3-dimensioal micro-structures. In this research, a micro-bellows actuator that is vertically moving was developed using the micro-stereolithography technology. When pressure was applied into the bellows, a non-contact actuating motion is generated. For actuation experiment, syringe pump and laser interferometer were used for applying pressure and measuring the displacement. Several hundreds micro-scale actuation was observed. And, to demonstrate the feasibility of proposed actuation principle, in this research, a micro-gripper was developed using half-bellows structure.
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Purpose of this study is to investigate the size-dependent mechanical properties in micron scale medium. Theories such as the couple stress theory and strain gradient theory explain that the deformation in the micron scale is dependent upon the size of the medium. Specimens of the cantilever type, bridge type and paddle type beam that have thickness of 900, 1000 and 1200 nm and width of 10, 20, 30 and
$50{\mu}m$ were fabricated by the MEMS technique. We carried out the bending and torsion test to measure the mechanical properties such as the young's modulus, yield strength and torsional rigidity using the AFM(Atomic Force Microscopy). -
Micro injection molding is a branch of micro system technology and has been under development for the mass manufacture of micro parts. Enhanced technological products like micro optical devices are entering the market. This paper presents fundamental research on the injection molding technique in micro fabrication. In order to successful manufacturing of micro plastic parts, it is necessary to research for development of micro-injection machine, machining of micro mold, decision of optimum injection conditions and the research for polymer material. Therefore in this study, in order to machining of micro mold, a mold core with microscopic V-shaped groove was tooled by ultra-precise tooling machine. The transcription experiments with a polymer, PMMA resin on the surface of core with Ni plating were carried out and surface profile of injected parts was measured with AFM.
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For precise micro-grooving and surface machining, ultrasonic cyclic elliptical cutting is proposed using two parallel piezoelectric actuators. The piezoelectric actuators are energized by sinusoidal voltages of varying phase which is essenstial to generating elliptical cutting. Experimental setup is composed of ultrasonic motor, single crystal diamond cutting tool, and precise motorized xyz stage. It is confirmed experimentally that the cutting performance, in terms of the cutting force, the burr formation, and the discontinuous chip formation is improved remarkably by applying ultrasonic elliptical vibration cutting.
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ELID(ELectrolytic In-process Dressing) grinding is an excellent technique for mirror grinding of various advanced metallic or nonmetallic materials. A polishing process is also required for elimination of scratches present on ELID grinded surfaces. MAP(Magnetic Assisted Polishing) has been used as a polishing method due to its high polishing efficiency and to its resulting in a superior surface quality. This study describes an effective fabrication method combining ELID and MAP of nano-precision mirror grinding for glass-lens molding mould, such as WC-Co, which are extensively used in precision tooling material. And for the optics glass-ceramic named Zerodure, which is extensively used in precision optics components too. The experimental results show that the combined method is very effective in reducing the time required for final polishing. The best surface roughness of the polished glass-ceramic was within 1.7nm Ra in this study.
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Imprint lithography is a promising method for high-resolution and high-throughput lithography using low-cost equipment. As with other nanoimprint methods, ultraviolet-nanoimprint lithography (UV-NIL) resolution appears to be limited only by template resolution, and offers a significant cost of ownership reduction when compared to other next generation lithography (NGL) methods such as EUVL and 157 nm lithography. The purpose of this paper is to suggest optimum values of control parameters of Imprio 100 manufactured by Molecular Imprint, Inc., which is the first commercially available UV-NIL tool, for sound nanoimprint. UV-NIL experiments were performed on Imprio 100 to find dispensing recipe for avoiding air entrapment. Dispensing recipe related to residual layer thickness and uniformity was optimized and 40 nm thick residual layer was achieved.
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In this paper, we investigate the characteristics of a piezoresistive AFM cantilever in the range of
$0\~30{\mu}N$ by using nano force calibrator (NFC), which consists of a high precision balance with resolution of 1 nN and 1-D fine positioning stage. Brief modeling of the cantilever is presented and then, the calibration results are shown. Tests revealed a linear relationship between the probing force and sensor output (resistance change), and the force vs. deflection. From this relationship, the force constant of the cantilever was calculated to 3.45 N/m with a standard deviation of 0.01 N/m. It shows that there is a big difference between measured and nominal spring constant of 1 N/m provided by the manufacturer s specifications. -
The study on the interaction forces of some biological materials is important to understanding biological phenomena and their application to practical purpose. This paper introduces a measuring technique for biological adhesive forces using the AFM(Atomic Force Microscope). Since no standardized thesis on adhesive forces exist, the adhesive forces is defined as adhesive forces against a hardened surface of biological materials. To grant the results are meaningful, which is based on the understanding the surface characteristics of biological materials using the AFM, a nominal value of average adhesive force per unit area should be measured. Therefore the modified AFM probe with small micro glass bead was proposed so that it can guarantee the required contact area for measuring the average adhesive forces. A pyrex glass substrate with circular patterns, which was fabricated by micromachining technique, is introduced in order to controll the contact area. The two types of mussel adhesive proteins, Celltak and recombinant-MGFP5, were tested by the proposed measuring method. The test results show that the adhesive force of the mussel adhesive proteins can be reliably measured by use of this method.
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Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.
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Abrasive jet machining is a well-known process for patterning window glass and mirrors. The technics is now being developed for the production structure with high precision. This paper describes erosion profile modeling of micro abrasive jet machining and compares with other researcher's model.
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This paper introduces design, fabrication and experiment process of a novel scanner for the high speed AFM(Atomic Force Microscope). A proper design modification is proposed through analyses on the dynamic characteristics of the existing linear motion stages using a dynamic analysis program, Recurdyn. Since the scanning speed of each direction is allowed to be different, the linear motion stage for the high-speed scanner of AFM can be so designed to have different resonance frequencies for the modes with one dominant displacement in the desired directions. One way to achieve this objective is to use one-direction flexure mechanism for each direction and to mount one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separates the frequencies of the two vibration modes with one dominant displacement in each desired direction, hence, the coupling between the motions in the two directions. In addition, a pair of actuators is used for each axis to decrease the cross talks in the two motions and gives a force large enough to actuate the slow motion stage, which carries the fast motion stage. After these design modifications, a novel scanner with scanning speed higher than 10 Hz can be achieved to realize undistorted images in the high speed AFM.
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In this study, the deposition of micrometer-scale metallic interconnects on LCD glass for the repair of open-circuit type defects is investigated. Although there had been a few studies Since 1980 s for the deposition of metallic interconnects by laser-induced chemical vapor deposition, those studies mostly used continuous wave lasers. In this work, a third harmonic Nd:YLF laser (351nm) of high repetition rates, up to 10 KHz, was used as the illumination source and
$W(CO)_6$ was selected as the precursor. General characteristics of the metal deposit (tungsten) such as height, width, morphology as well as electrical properties were examined for various process conditions. Height of the deposited tungsten lines ranged from 35 to 500 nm depending on laser power and scan speed while the width was controlled between$3\~50{\mu}$ using a slit placed in the beam path. The resistivity of the deposited tungsten lines was measured to be below 1$O\cdot{\mu}m$ , which is an acceptable value according to the manufacturing standard. The tungsten lines produced at high scan speed had good surface morphology with little particles around the patterns. Experimental results demonstrated that it is likely that the deposit forms through a hybrid process, namely through the combination of photolytic and pyrolytic mechanisms. -
Surface modified carbon nanotubes were applied into the epoxy composites to investigate its tribological property. Carbon nanotubes reinforced epoxy composites were fabricated by casting. Effects to the tribological property of loading concentrations and types of surface modification of carbon nanotubes were investigated under sliding condition using linear reciprocal sliding wear tester. The results show that the small amount of carbon nanotubes into the epoxy exhibited lower weight loss than the pure epoxy. It is concluded that the effect of an enormous aspect ratio of carbon nanotubes surface area which wider than conventional fillers that react as interface for stress transfer. As increased the contents of carbon nanotubes, the weight loss from the wear test was reduced. And the surface modified carbon nanotubes show better tribological property than as produced carbon nanotubes. It is due that a surface modification of carbon nanotubes increases the interfacial bonding between carbon nanotubes and epoxy matrix through chemical bonding. Changes in worn surface morphology are also observed by optical microscope and SEM for investigating wear behaviors. Carbon nanotubes in the epoxy matrix near the surface are exposed, because it becomes the lubricating working film on the worn surface. It reduces the friction and results in the lower surface roughness morphology in the epoxy matrix as increasing the contents of the carbon nanotubes.
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Carbon nanotubes exhibit strong fluorescence emissions in the region of near infrared regions where most biomolecules are transparent. Such signals are highly sensitive to environment variations as well as adsorption of specific biomolecules. In this research, single walled carbon nanotubes(SWNTs) are assembled with different types of DNAs and used to target specific types of DNAs. Dot blot investigations and corresponding raman spectroscopy observations demonstrated excellent selectivity of carbon nanotube-DNA bioconjugates. The results show possibility of using SWNT as generic nano-bio markers for precise detection of different kinds of genes.
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To imprint 70-nm wide line-patterns, we used a newly developed ultraviolet nanoimprint lithography (UV-NIL) process in which an elementwise patterned stamp (EPS), a large-area stamp, and pressurized air are used to imprint a wafer in a single step. For a single-step UV-NIL of a 4' wafer, we fabricated two identical
$5'\times5'\times0.09'(W{\times}L{\times}H)$ quartz EPSs, except that one is with nanopatterns and the other without nanopatterns. Both of them consist of 16 small-area stamps, called elements, each of which is$10\;mm\;\times\;10\;mm$ . UV-curable low-viscosity resin droplets were dispensed directly on each element of the EPSs. The volume and viscosity of each droplet are 3.7 nl and 7 cps. Droplets were dispensed in such a way that no air entrapment between elements and wafer occurs. When the droplets were fully pressed between ESP and wafer, some incompletely filled elements were observed because of the topology mismatch between EPS and wafer. To complete those incomplete fillings, pressurized air of 2 bar was applied to the bottom of the wafer for 2 min. Experimental results have shown that nanopatterns of the EPS were successfully transferred to the resin layer on the wafer. -
Nano imprint Lithography (NIL) is regarded as one of the next-generation lithography technologies with EUV lithography, immersion lithography, Laser interference lithography. Because a Si wafer stamp and a quartz stamp, used to imprinting usually are very expensive and easily broken, it is suggested that master stamp is duplicated by PDMS and the PDMS stamp uses to imprint .For using the PDMS stamp, a thermally curable monomer resin was used for the imprinting process to lower pressure and temperature. As a result, NIL patterns were successfully fabricated.
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Multi-walled carbon nanotubes were purified by using the nitric acid after the mechanical cutting, which carboxylic group might be introduced into the surface of nanotubes. To enhance the dispersion of CNTs, carboxylic groups were substituted in the reaction with octadecyl amine containing a long alkyl group. Nanofibers were manufactured by electrospinning, the solution that mixed with PMMA and ODA-fuctionalized CNTs in dimethyl formamide and dispersed with ultrasonication. Diameter and alignment of nanofibers with various electrospinning parameters, such as the CNT and PMMA concentration in solution, the applied voltage, and the distance to the collector were investigated. As a result, the nanofiber diameter was increased with the increment of PMMA concentration, whereas it was reduced as the applied voltage and the spinning distance was increased. The spinning area became smaller with the distance. The nanofibers were formed without the defect on surface and well aligned in a specific concentration of PMMA and nanotubes.
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A numerical simulation method is developed to analyze the dynamic response of a cantilever switch, which is driven by electrostatic force and a basic component of electro-mechanical coupled system. First, point-charges model on conductor is proposed as a lumped parameter of electrical part. Then, this model is easily incorporated into a multi-body dynamics analysis algorithm, the generalized recursive dynamics formula previously developed by our research group. The resulting motion of a coupled overall system is formulated as a differential algebraic equation form including electrical and mechanical variables together. The equation is simultaneously solved in every time step. To implement this approach into the useful dynamics analysis tool, we used multibody dynamics software (RecurDyn) based on the generalized recursive formula using relative coordinate. The developed numerical simulation tool is evaluated by applying to many different driving condition and switch configuration. The final analysis model will be added to RecurDyn as a basic module for dynamics analysis of electro-mechanical coupled system.
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In this paper, probabilistic distribution of fatigue life of chassis component is determined statistically by applying the design of experiments and the Pearson system. To construct
$p-\varepsilon-N$ curve, the case that fatigue data are random variables is attempted. Probabilistic density function(p.d.f) for fatigue life is obtained by design of experiment and using this p.d.f fatigue reliability about any aimed fatigue life can be calculated. Lower control arm and rear torsion bar of chassis component are selected as examples for analysis. Component load histories, which are obtained by multi-body dynamic simulation for Belsian load history, are used. Finite element analysis are performed using commercial software MSC Nastran and fatigue analysis are performed using FE Fatigue. When strain-life curve itself is random variable, probability density function of fatigue life has very little difference from log-normal distribution. And the case of fatigue data are random variables, probability density functions are approximated to Beta distribution. Each p.d.f is verified by Monte-Carlo simulation. -
The design of experiments are used for optimal design of formed tools to machine automobile bearing rubber seal die, which is classified into the high precision rubber mold. The clearance angle, rake angle and the length cutting edge are considered as the factors. The cutting force is selected to be a characteristic value and compared with the mean tool wear and life by repeated experiments. The design of the experiment is based on the repeated one-way factorial design, which finds the significance of the factors and the best level to predict the tool life by using ANOVA and regression.
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Nowadays, because of the frequent market change and variable customer's requirements, product's life-circle is becoming shorter. So, automobile companies are forced to rapidly develop new products and efficiently reduce both manufacturing lead time and cost, with the world level quality. Among them, Press Die is not only just a bottle neck but also an important resource exerting certain effect in quality of car body appearance. Since 2000, due to efforts to reduce the time of design phase, many companies have used 3D design methods. Actually the method didn't reduce the period of design because the company didn't develop the best practice. This paper wish to solve this problem by modular based hybrid dies template.
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Metallic sandwich plates with Inner dimpled shell subjected to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high quality precision and bonded with same material skin sheets by resistance welding or adhesive bonding process. Optimized shape of inner dimple is a hemispherical shell to minimize weight without failure, including face yielding, face buckling and inner dimple buckling. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times than solid plates with same strength
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Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed in multi-cavity injection mold. These filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during the injection molding processing. This paper presents a solution of these filling imbalances by using runner core pin which creates a symmetrical shear distribution within runner and the effects on filling imbalance when modifying a shape of runner core pin. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed. In addition we investigated how filling imbalances were affected by shape of runner core pin.
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Many impact or drop test researches of home appliances are published, but those of toys cannot be found easily. External impacts are the primary causes of fracture of toys. For impact proof design, the finished product should pass an impact test after molding design. There are several international toy safety standards or requirements such as US CPSC(Consumer Product Safety Commission), ASTM F963-96a, EN71 and so on. The puppy robot which patrols around the house, namely, the watchdog was selected to investigate toy safety because it has considerable weight and outer panels are made of plastics. First the model of watchdog robot was obtained by 3 dimensional scan. Surface data can be generated from 3D polygon data of the watchdog. A reliable drop simulation method for the watchdog was established using Pam-crash program according to Korean toy safety standards. When there is a low impact allowance value, the molding design should be reinforced or changed. It was found that the maximum impact stress reaches the ultimate stress of panel material.
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The concept of jigs and fixtures makes it possible to build fixtures that can be dismantled at project completion. Since this concept is modular, it is not limited to any particular unit shapes or sizes. Various standards assure that each component assemble rapidly, to get precision and accuracy. Best suited for prototype and low volume production, as well as, start-up or zero-runs, it can also substitute for damaged dedicated fixtures to minimize down-time. It need to do DB for each part by Pro/Engineer and to assemble before manufacturing. In the future will assemble each of clamping and position parts by automation.
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In this paper, we propose the collaborative design system with which we can simultaneously modify the actual 3D CAD model by the remote control and have interaction on it. It enables instantaneous decision making among the multiple disciplines in distributed locations using the function of simultaneous access and video conference. It also provides the method of managing the consistency between design entities. This system consists of Collaborative Management Server, File Server, Solid Modeler Client, Remote Control Module and Client Module.
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Material selection is one of the important activities in design and manufacturing. A selected material at the conceptual design stage affects material properties of the designed part as well as manufacturability and cost of the final product. Unfortunately there are not many accessible material databases that can be used for design. In this research, a web-based material database was constructed. In order to assist designers to compare different materials, two-dimensional and three-dimensional graphs were provided. Using these graphical tools, multi-dimensional comparison was available in more intuitive manner. To provide environmental safety of materials, the database included National Fire Protection Association publication Standard No.704. The web-based tool is available at http://fab.snu.ac.kr/matdb.
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A light guide panel (LGP) is an element of the LCD back light unit, which is used for display devices. In this study, a laser marking process is applied to the fabrication of light guide panels as the new fabrication process. In order to obtain a light guide panel which has high luminance and uniformity, four principal parameters such as power, scanning speed, ratio of line gap, and number of line were selected as important factors. A Web-based design tool was developed to generate patterns of light guide panel, and the tool may assist the designer to develop optimized patterns. Topcon-BM7 was used for luminance measurement of each specimen 100mm
$\times$ 100mm area. By Taguchi method optimized levels of each parameters such as 40W of power, 30mm/s of scanning speed, 100:50 ratio of pattern gap, and 90 line of pattern were found by Taguchi method. -
Distal 3D Real Object Duplication System(RODS) consists of 3D Scanner and Solid Freeform Fabrication System(SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and a industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer(SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. Also, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Multi-Laser Sintering(SMLS) process and 3-axis dynamic Focusing Scanner for scanning large area instead of the existing
$f\theta$ lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, scan spacing. Now, this study is in progress to eveluate the effect of experimental parameters on the sintering process. -
Rapid Prototype has been used to design and Production of part in a variety of fields ; Car, Electronic products, Aviation, Heavy industry etc. Moreover development of hardware gave rise to use the method of Rapid Prototype more and more at high precision and complicated shapes. Expecially, to be using process of products that shapes of Micro-hole ; Cellular phones, Antennas, Jewels, Semi conductor cases. In case of Micro-shape, precision of the shape turns on various condition ; Laser size, Laminate height, scanning speed, overcure, viscosity of resin, etc. Sometimes breaks out the case that interner hole of shape is blocked by viscosity of resin. The phenomenon has solved easily to reduce viscosity of resin. But, in case of the method brings about the problem that strength goes down in actuality products hardening. This study on verify to change of shape of Micro-hole and makes the semiconductor case which has shape of Micro-hole by using resin of higher viscosity, scanning speed and overcure
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In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience for clarity. Therefore, a new rapid manufacturing process using the hot tool, Rapid Heat Ablation process (RHA), has been developed. In this paper, the hot tool for RHA process is devised to minimize radius of heat affected zone and also investigated for verification. TRIZ well-known as creative problem solving method is applied to overcome the contradictive requirements of the hot tool. For the detailed design of the hot tool, numerical model is established with several assumptions. Based on the numerical results, surface temperature is measured with K-type thermocouple at the predetermined location. Numerical and experimental results show that the devised hot tool fulfils its requirements. It verifies the practicality of hot tool that the hemisphere shape is ablated using the hot tool with stair structure.
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In the industry, three-dimensional coloring has been needed for realistic prototype from rapid prototyping. Z-corporation developed a 3D printer which provides three-dimensional colored prototype. However, the existing process cannot be adopted to models from other rapid prototyping process. In addition, time and cost for manufacturing colored prototype still remain to be improved. In this study, a new coloring process using ink-jet head is proposed for color printing on three-dimensional prototype surface. Process parameters such as the angle and the distance between ink-jet nozzle and the three-dimensional surface should be investigated from experiments. The correction matrix according to sloped angle to minimize the distortion of 2D image was proposed by analysis of printing error. Therefore, approximated method for angle and discrete length according to the radius of curvature for printing on the curved surface was proposed. By printing image on the doubly curved surface, the method was verified. As a practical example, helmet was chosen for printing images on the curved surface. The character images were applied with approximated method for angle and discrete length and was printed on the helmet surface.
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Rapid prototyping (RP) technologies are mainly performed by layered manufacturing (LM) process which manufactures 3D physical objects by depositing 2D sections in a direction. Thus, deformations are apt to occur in overhanging area of the RP processed part. Also, excessive adhesion between part and platform of the RP apparatus is generated. In order to prevent these problems, most of the RP technologies adopt support structure. Main element to support a part in the support structure is strand. In actual field, however, the number of strand is determined by the software operating reference guide or RP system operator's experience. In this paper, a methodology to determine the optimal strand spacing is presented through experiments and measurements for the SL part deformation by change of strand spacing and part weight in the support structure of the stereolithography.
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The technology of rapid prototyping (RP) is used for design verification, function test and fabrication of prototype. The current issues in RP are improvement in accuracy and application of various materials. In this paper, a hybrid rapid prototyping system is introduced which can fabricate nano composites using various materials. This hybrid system adopts RP and machining process, so material deposition and removal is performed at the same time in a single station. As examples, micro gears and a composite scaffold were fabricated using photo cured polymer with nano powders such as carbon black and hydroxyapatite. From the micro gear samples the hybrid RP technology showed higher precision than those made by casting or deposition process.
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In this paper, multi-pass roll forming process is simulated with a commercial FEM software. From these simulations, detects like excessive thickness decrease were estimated. And effects of springback, idle roll without force, and self-contacts between materials were also predicted. As a result, the defects of the forming process and the numbers of the roll pass can be decreased. And these analyses will be able to design the optimal roll forming process.
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Ball end milling is widely used in machining free surfaces. It is important to predict machining forces in this machining. In this study, cutting forces are predicted for different machining conditions in ball end mill contouring machining. These cutting forces influence tool deflection. In this study tool deflection is calculated for various cutting conditions. The model developed in this study can be used to predict machining accuracy in contouring machining.
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Five DOF motion errors of a hydrostatic bearing table driven by the coreless type linear motor were compensated utilizing the active controlled capillaries in this study. Horizontal linear motion and yaw error were simultaneously compensated using two active controlled capillaries and vertical linear motion, pitch and yaw error were also simultaneously compensated using three active controlled capillaries. By the compensation, horizontal linear motion accuracy and yaw were improved from 0.16
${\mu}m$ and 1.96 arcsec to 0.02${\mu}m$ and 0.03 arcsec. Vertical linear motion accuracy, pitch and roll were also largely improved from 0.18${\mu}m$ , 2.26 arcsec and 0.14 arcsec upto 0.03${\mu}m$ , 0.07 arcsec and 0.02 arcsec. The compensated motion errors were within the range of measuring repeatability which was${\pm}0.02\;{\mu}m$ in the linear motion and${\pm}0.05$ arcsec in the angular motion. From these results, it is found that the motion error compensation method utilizing the active controlled capillaries are very effective to improve the five motion accuracies of the hydrostatic bearing tables. -
In this paper, For improving the positioning accuracy of hydrostatic table, relationship between temperature of atmosphere and thermal characteristics of hydrostatic table is analyzed, and influence of thermal characteristics on positioning accuracy is also analyzed experimentally. From the experimental results, it is confirmed that positioning error and repeatability is
$0.21{\mu}m\;and\;0.18{\mu}m$ when the laser scale which has$0.01{\mu}m$ of resolution is used as feed-back unit. and also confirmed that thermal deformation of scale and supporter, which occurs by the temperature variation of atmosphere, works as limit of repeatability in long time operation. -
The high vacuum in a electron beam lithography is basic condition, because electron beam vanish by collision with air molecules in generally atmosphere. To make high vacuum state, the vacuum control valve is essential. Most vacuum control valve are manual units. So, user of manual vacuum valve must have understanding vacuum process to change from low vacuum to high vacuum state. The user of electron beam lithography are troubled with operation of manual vacuum valve, in case the vacuum chamber is frequently open. In this paper, the design and performance test of auto vacuum control valve for electron beam lithography are described. With the auto vacuum control valve, the high vacuum level can reach 2.8E-5 Torr.
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The feed drive inclination significantly influences product quality, machine tool accuracy and life time. However, the accurate measurement of the inclination needs the skilled engineers and the accurate leveling instruments such as spirits or electric levels. In this study a novel methodology for the estimation of inclination angle of machine tool feed drive is proposed. The proposed methodology utilizes the motor current signals and a new mathematical model of machine tool feed drive considering inclination. The experiment results showed that the proposed method successfully estimates the inclination angle, as well as newly proposed model also enhances the accuracy of the machine tool feed drive model by introducing the inclination effects.
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Reconfigurability of machine tools is one of the critical factors to realize the responsive manufacturing systems to satisfy the mass-customization production. This paper presents the methods to model and simulate the machine tools on Internet in response to change in the machining requirements. Specifically, a set of module combination rules and a modeling method of the structure of machine tools using connectivity graph are developed. In response to the user requirements, kinematic relations and structures of machine tools can be derived using the module combination rules and connectivity graph relationships. Internet-based simulator of machine tools is implemented and presented. The developed machine tool simulator can be used to verify the structure of machine tools derived from the user requirements.
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The guide-ways of precision machine tools are one of important element of machine tools. It has usually a pair of surfaces for constraint of one direction with bearing. In the case of precision machine tools, non-contact bearing such as hydrostatic bearing and aerostatic bearing is adopted usually. In this case, profiles of rails has effect on straightness and the clearance of bearing has effect on stiffness of guide way, which changes to higher if clearance changes to smaller. The clearance is varied along moving table according to relative distance of pair of rails. The relative distance of pair of rail can be divided by three properties. First and second properties are straightness of each pair of rail and bearing pad. And, third is parallelism about pair of rails and pairs of bearing pad. There are several methods for measuring straightness of each surface such as reversal method, sequential two point method, and way straightness. These straightness measuring methods are always acquiring deviation of profile from eliminating linear fitted inclined line and don't have the information of parallelism. Therefore, to get the small clearance for high stiffness, the straightness of rail and bearing pad and parallelism about pair of rails and pair of bearing pads are measured for correction such as regrinding, reassembling and lapping. In this research, new and easy method for measuring parallelism of pair of rails is suggested. Two displacement probe and sensor stage, which is carry on the displacement sensor, are needed. The simulation and experiment was accomplished about pair of horizontal guide way to confirm the measurement of parallelism. And, the third probe is added to measure the straightness of each rails by sequential two point method. From the estimation of combined these two methods, it is confirmed that the profiles of a pairs of rails can be measured.
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The tilting pad journal bearings have been widely used to support high pressure/high rotating turbine rotors owing to their inherent dynamic stability characteristics. However, fatigue damages in the upper unloaded pads and the break of locking pins etc. by pad fluttering are continuously taken place in the actual steam turbines. The purpose of this paper is to develop a new bearing model that can prevent bearing problems effectively by pad fluttering in a tilting pad journal bearing. A new bearing model which has a wedged groove is suggested from the studies of fluttering mechanism performed by previously research works. The fluttering characteristics of the upper unloaded pad are studied experimentally in order to verify the reliability of a new bearing model. It can be known that the phenomenon of pad fluttering nearly does not occurred in the new bearing model under the various experimental conditions. And it is observed that any kinds of bearing failures by pad fluttering does not detect in the application of acture steam turbines.
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The robot to search and rescue is used in narrow space where human cannot approach. In case of this robot, it can overcome obstacles such as wrecks or stairs etc. Also, this robot can do various locomotion for each object. In this reason, an articulated robot has advantages comparing with one module robot. However, the existing articulated robot has limits to overcome vertical passages. For expanding contacted territory of robot, a novel mechanism is demanded. In this paper, the novel mechanism of articulated mobile robot is designed for moving level ground and vertical passages. This paper proposes to change wheel alignment. The robot needs two important motions for passing vertical passages like pipe. One is a motion to press wheels at wall for not falling into gravity direction. The other is a motion that wheels contact a vertical direction of wall's tangential direction for reducing loss of force. The mechanism of the robot focused that two motions can be acted to use just one motor. Length of each link of robot is optimized that wheels contact a vertical direction of wall's tangential direction through kinematic modeling of each link. The force of pressing wall of robot is calculated through dynamic modeling. This robot composes four modules. This mechanism is confirmed by dynamic simulation using ADAMS program. The articulated mobile robot is elaborated based on the results of kinematic modeling and dynamic simulation.
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The incremental forming process employs several tens or hundreds of continuous local strokes, so the entire process is difficult to analyze due to much computation time and large computer memory. The objective of this work is to propose a new numerical scheme of the finite element method, automatic expansion of domain (AED), and to reduce computation time and computer memory. In the AED scheme, an effective analysis domain in each local forming step is defined and then the domain is automatically expanded in accordance with the repeated process. In order to verify the validity of the criterion for the AED scheme and the applicability of the AED scheme, two-dimensional incremental plane-strain forging process is first analyzed using the proposed scheme with various criteria and full domain. In addition, three-dimensional incremental radial forging process is analyzed to verify the applicability of the proposed scheme to a practical incremental forging process.
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The cycloid reducer has very high efficiency, high ratios, high stiffness and small size, in comparison with a conventional gear mechanism, which makes it an attractive candidate for limited space and precision application such as industrial robot. There are several publications on analysis and design of the cycloid reducer, however, it was assumed that the contact stiffness of pin rollers and cycloid disk is constant regardless of their contact geometry. Moreover, the torsional stiffness of the cycloid reducer couldn't be calculated due to the assumption. In this paper, we present a new procedure of calculating torsional stiffness of the cycloid reducer using Hertz contact theory. First, conventional force analysis of the cycloid reducer is briefly reviewed. Then, iterative numerical calculation procedure of the contact stiffness is proposed based on the Hertz contact theory where the contact stiffness depends on the contact force. In addition, total torsional stiffness of the cycloid reducer is estimated considering its rolling element bearing stiffness. The torsional stiffness of the cycloid reducer is dominated by the rolling element bearing stiffness since the contact stiffness of the cycloid disk is too large.
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Recently engineering systems problems become quite large and complicated. For those problems, design requirements are fairly complex. It is not easy to design such systems by considering only one discipline. Therefore, we need a design methodology that can consider various disciplines. Multidisciplinary Design Optimization (MDO) is an emerging optimization method to include multiple disciplines. So far, about seven MDO methodologies have been proposed for MDO. They are Multidisciplinary Feasible (MDF), Individual Feasible (IDF), All-at-Once (AAO), Concurrent Subspace Optimization (CSSO), Collaborative Optimization (CO), Bi-Level Integrated System Synthesis (BLISS) and Multidisciplinary Optimization Based on Independent Subspaces (MDOIS). In this research, the performances of the methods are evaluated and compared. Practical engineering problems may not be appropriate for fairness. Therefore, mathematical problems are developed for the comparison. Conditions for fair comparison are defined and the mathematical problems are defined based on the conditions. All the methods are coded and the performances of the methods are compared qualitatively as well as quantitatively.
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In feature-based multi-resolution modeling, the features are rearranged according to a criterion for the levels of detail (LOD) of multi-resolution models. In this paper, two different LOD criteria are investigated and discussed. The one is the volumes of subtractive features, together with the precedence of additive features over subtractive features. The other is the volumes of features, regardless of whether the feature types are subtractive or additive. In addition, the algorithms to define and extract the LOD models based on the criteria are also described. The criterion of the volumes of features can be used for a wide range of applications in CAD and CAE in virtue of its generality.
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The objective of this research work is to investigate into static and dynamic characteristics of ISB panels with the expanded metal as an internally structured material. In order to investigate static and dynamic characteristics of ISB panels, several experiments, the tensile test, three-point bending test and impact test, are carried out. From the results of the experiments, the mechanical properties, bending stiffness and impact absorption energy of the ISB panel have been obtained. In addition, it has been shown that the static and dynamic characteristics of ISB panel are highly dependent on the crimping angle of the pyramidal structure for the expanded metal.
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A limit switch box is used for a indicator of a valve actuator. This device indicates an opening and closing of a valve or throttle in a valve actuator. In a ship, equipments are required safety and robustness because of a rough environment and a specific condition during a voyage. However, the limit switch box is used in an indoor environment generally. In order to evaluate the endurance of the limit switch box used in an indoor environment, the endurance tests against salt water have been conducted. Experiment results showed that the limit switch box was corroded severely. Thus, this study developed a new limit switch box which can be used at an outdoor environment. The housing of the developed limit switch box was made by an stainless steel to prevent corrosion.
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For an analysis of nonlinear dynamic behavior in carbon nanotube(CNT) an electrostatic force of CNT was investigated. The boundary condition in the CNT was assumed to clamped-clamped case at both ends. This type of CNT is widely used as micro and nano-sensors. For larger gaps in between sensor and electrode the van der Waals force can be ignored. The electrostatic force can be expressed as linear form using Taylor series. However, the first term of the series expansion was investigated here. The electrostatic force From this study we can conclude that for larger gaps the electrostatic force play an important role in determining the deflections as well as the pull-in voltage of simply supported switches.
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A seamless analysis of complex geometry is one of greatly interesting topic. However, there are still gaps between the industrial applications and fundamental academic studies owing to time consuming modeling process. To resolve this problem, an auto mesh generation program based on grid-based approach has been developed for IT-product in the present study. At first, base mesh and skin mesh are generated using the information of entities which extracted from IGES file. Secondly the provisional core mesh with rugged boundary geometry is constructed by superimposing the skin mesh as well as the base mesh generated from the CAD model. Finally, the positions of boundary nodes are adjusted to make a qualified mesh by adapting node modification and smoothing techniques. Also, for the sake of verification of mesh quality, the hexahedral auto mesh constructed by the program is compared with the corresponding tetrahedral free mesh and hexahedral mapped mesh through static finite element analyses. Thereby, it is anticipated that the grid-based approach can be used as a promising pre-processor for integrity evaluation of various IT-products.
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In mechanical design part, though many design methodologies have been developed, most of them are applicable for detailed design. Therefore, when people had to do conceptual design, they relied on their individual creativity. To improve this phenomenon, some methodologies are developed such as TRIZ and axiomatic design. In this paper, both TRIZ and axiomatic design methodologies will be reviewed. In addition, some papers which contain conceptual design case study will be also dealt with. These case studies are results of application both axiomatic design and TRIZ methodology.
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Carbon fiber polymeric composites have been widely used in bearing materials under high pressure without oil-lubrication due to their self-lubricating characteristics. However, the severe wear of carbon composite surface occurs due to the generation of wear debris when the pressure applied on the composite surface is higher than the critical value of composite surface. In this work, in order to remove wear debris continuously during sliding operation, composite specimens with many micro-grooves on their sliding surfaces were devised. To investigate the effect of wear debris on the tribological behavior of carbon/epoxy composites, dry sliding tests were performed with respect to applied pressure using the composite specimens with and without micro-grooves. From the measurement of friction coefficients and wear rates, a model for the effect of wear debris on the friction and wear of composites was proposed.
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Dynamic model of the Korea standardized rubber-tired AGT light rail vehicle, and boundary conditions between vehicle and infrastructures (running track, guidance rail) were defined to analyze vehicular vibration behaviors occurred at the worst condition. Using the commercialized software RecurDyn, vibration accelerations of car body and bogies were analyzed. Based on the Korea performance test criteria for urban transit, vertical and lateral vibration of car body were calculated and evaluated. As the results, the Korea standardized rubber-tired AGT light rail vehicle satisfied the performance criteria and design requirement.
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Hydraulic excavators have been popular devices in construction field because of its multi-workings and economic efficiency. The mathematical models of excavators have many nonlinearities because of nonlinear opening characteristics and dead zone of main control valve, oil temperature variation, etc. The objective of this paper is to develop a simulator for hydraulic excavator using AMESim. Components and whole circuit are expressed graphically. Parameters and nonlinear characteristics are inputted in text style. From the simulation results, fixed spring stiffness of MCV can't satisfy accuracy of spool displacement under whole P-Q diagrams. Closed loop type MCV containing proportional gain is proposed in this paper that can reduce displacement error. The ability of closed loop MCV is verified through comparing with normal type MCV using AMESim simulator. The simulator can be used to forecastexcavator behavior when new components, new mechanical attachments, hydraulic circuit changes, and new control algorithm are applied. The simulator could be a kind of development platform for various new excavators.
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Currently, the marketable truck has the cab tilting system which highly absorb the vibrations and impacts of cab. The cab tilting system is equipped with the hydraulic system for maintenance and inspection of truck. And it is very important to improve the user's feeling of driving and convenience. To have the better performance, it is important to confirm the dynamic characteristics of each parts of the system. In this study, a mathematical model of the system was derived and the parameters in the model were identified from experimental data. The results of the simulation were compared with those of experiments. These results of the computer simulation and experiments show that the proposed analysis can be applied effectively to design the system. Our results can be utilized for the future research to improve the capability of the truck cab tilting system.
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This paper suggests gait analysis and gait simulation method using Gait Motion Capture equipment and plantar pressure measurement system. The gait of normal person and how it will be effected by added weight with wearing military equipments are studied by suggested method. It is measured that a change of gait pattern when wears military equipments with Korean male adult(height 180 cm, weight 70 kg) and simulated its results.
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A total knee replacement is an extremely 'position-sensitive' operation; a malposition or a malalignment of the components will lead to a breakage of the component, a fracture around the knee prosthesis, and the limitation of range of the motion, etc. In a conventional total knee replacement, surgeons have to select an appropriate prosthesis according to the shape of the surgical region. A wrong selection may give rise to side effects or to need re-operation. Nevertheless, it is so difficult to choose the most proper prosthesis out of various kinds of prosthesis. This paper presents a surgical planning system for the total knee replacement with an operation simulating method in order to determine the parameters for the total knee replacement operation. We select an alignment axis and a resection angle as major operation parameters in the total knee replacement operation, and introduce the method to determine the major operation parameters with the operation simulator we developed. The simulator is used to determine operation parameters for optimized operations, to select the most appropriate prosthesis, and to analyze the prospective problems of the operation.
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In this paper, the prototype of a walking guide robot with tactile display is introduced, and the psychophysical experiment of the tactile recognition for a tactile display is carried out and analyzed. The objective of this research is the development of a walking guide robot for the blind to walk safely. A walking guide robot consists of a guide vehicle and a tactile display device. A guide vehicle, located in the front of the walking blind, detects the obstacle using ultrasonic sensors and offers the information of position and walking direction acquired from GPS module to the walking blind by voice. The tactile display device, located in the handle which is connected with the guide vehicle by cane, offers the processed obstacle information such as position, size, moving, shape of obstacle and safe path, etc. The psychophysical experiments for the threshold of perception and recognition ability of tactile stimulation are carried out by the estimation of the subject group. As a result the appropriate tactile stimulus intensity and frequency to recognize tactile stimulation effectively are discussed and derived.
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This study investigated changes of mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae of the ovariectomised(OVX) rat. In previous researches, there were many studies for morphology of osteoporotic bones based on Micro-CT (Micro - Computed Tomography). However, there were few studies for detecting and tracking changes of mechanical characteristics in the trabecular bone and cortical bone of the lumbar vertebrae for the OVX rat. For this study, one female Sprague-Dawley rat was used: an OVX rat. The 4th lumbar of the OVX rat was utilized as a specimen. Detecting and tracking changes of mechanical characteristics could be investigated in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat using In-vivo Micro-CT. An OVX rat was scanned at week 0 (just before surgery), at week 4, and week 8 after surgery. Micro finite element(
${\mu}\;FE$ ) analysis was used to investigate mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat. -
An orthopedic surgeon normally gets the operational parameters of total knee arthroplasty from medical images(CT, MRI). Anatomical axis, mechanical axis, the width and height of femur, or tibia are the most important parameters related with accomplishment of TKA. This paper presents a methodology of simulation that virtually operates TKA according to 2D medical images. Using this simulator, some important parameters for operation can be achieved before hand. The simulator provides the 3D computational model of a knee joint and then derives the proper size of implant corresponding to the joint. The whole process of TKA can be simulated such as clipping a knee joint, assembling the joint and its implants, visualizing all the operation steps, deriving some crucial parameters such as anatomical axis and cutting thickness, and predicting the result of TKA. Some examples are given and discussed to validate the methodology.
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The purpose of this study was to analyze the muscular force of swing using the soft golf club in comparison with the muscular force of swing using normal golf club. The subject was normal adult (twenties) and performed swing motion using normal and soft golf club. And then we compared muscular power soft golf club with normal golf club of the subject. The muscular power of the subject was measured by MP 100(BIOPAC Systems, Inc.). For the analysis of muscular power of swing using soft golf club, we measured EMG(Electromyography) of the subject. The position of muscle was deltoid, latissimus dorsi, external oblique and rectus abdominis of the upper limbs and rectus femoris, biceps femoris, gastrocnemius and soleus of the lower limbs. The result of experiment, muscle pattern of swing using soft golf club was similar to pattern of swing using normal golf club and muscular power of subjects using the soft golf was smaller than normal golf.
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Although several artificial disc designs have been developed for the treatment of discogenic low back pain, biomechanical change with its implantation was rarely studied. To evaluate the effect of artificial disc implantation on the biomechanics of functional spinal unit, nonlinear three-dimensional finite element model of L4-L5 was developed with 1-mm CT scan data. Two models implanted with artificial discs, SB
$Charit\acute{e}$ or Prodisc, via anterior approach were also developed. The implanted model predictions were compared with that of intact model. Angular motion of vertebral body, force on spinal ligaments and facet joint, and the stress distribution of vertebral endplate for flexion-extension, lateral bending, and axial rotation with a compressive preload of 400 N were compared. The implanted model showed increased flexion-extension range of motion and increased force in the vertically oriented ligaments, such as ligamentum flavum, supraspinous ligament and interspinous ligament. The increase of facet contact force on extension were greater in implanted models. The incresed stress distribution on vertebral endplate for implanted cases indicated that additinal bone growth around vertebral body and this is matched well with clinical observation. With axial rotation moment, relatively less axial rotation were observed in SB$Charit\acute{e}$ model than in ProDisc model. -
Soft tissue characterization and modeling based on living tissues has been investigated in order to provide a more realistic behavior in a virtual reality based surgical simulation. In this paper, we characterize the nonlinear viscoelastic properties of intra-abdominal organs using the data from in vivo animal experiments and inverse FE parameter estimation algorithm. In the assumptions of quasi-linear-viscoelastic theory, we estimated the nonlinear material parameters to provide a physically based simulation of tissue deformations. To calibrate the parameters to the experimental results, we developed a three dimensional FE model to simulate the forces at the indenter and an optimization program that updates new parameters and runs the simulation iteratively. The comparison between simulation and experimental behavior of pig intra abdominal soft tissue are presented to provide a validness of the tissue model using our approach.
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Advances in Information Technology and in Biomedicine have created new uses for CAD technology with many novel and important biomedical applications. Such applications can be found, for example, in the design and modeling of orthopedics, medical implants, and tissue modeling in which CAD can be used to describe the morphology, heterogeneity, and organizational structure of tissue and anatomy. CAD has also played an important role in computer-aided tissue engineering for biomimetic design, analysis, simulation and freeform fabrication of tissue scaffolds and substitutes. And all the applications require precision geometry of the organs or bones of each patient. But the geometry information currently used is polygon model with none solid geometry and is so rough that it cannot be utilized for accurate analysis, simulation and fabrication. Therefore a case study is performed to deduce a transformation method to build free form surface from a rough polygon data or medical images currently used in the application. This paper describes the transformation procedure in detail and the considerations for accurate organ modeling are discussed.
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Generally, we take a bath to obtain a clean body as well as a good health. Human body generates various physical and emotional changes by stimulations of therapeutic effect of heat and hydraulic pressures. Accordingly, we can obtain not only relaxations but also effects of hydrotherapy. The survey of bathing/showering behaviors and therapeutic effect of heat reactions present elementary data for development of a bathing/showering system. However, there are few existing data for bathing/showering behaviors and effects. Consequently, surveys were performed to know patterns of bathing and showering, and relations between physiological changes and water temperature were examined by partial bathing on human body in this study.
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To investigate the relationship between BMD, micro-structural and mechanical properties in intertrochanteric trabecular bone, the PIXI-mus2 system, micro-CT and FE model were used. The purpose of this study were (1) to apply high-resolution imaging techniques (micro-CT imaging) in combination with new computer modeling techniques (FEA) to quantify 3D microstructural and biomechanical properties of trabecular bone in the intertrochanteric region, and (2) determine if the prediction of bone elastic constant can be improved with structural index.
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Carbon nanotube actuator, working under physical conditions (in aqueous solution) and converting electrical energy into mechanical energy directly, can be a good substitute for artificial muscle. The carbon nanotube actuator simulated in this paper is an isotropic cantilever type with an adhesive tape which is sandwiched between two single-walled carbon nanotubes. For predicting the static and dynamic characteristic parameters, the analytical model for a 3 layer bimorph carbon nanotube actuator is developed by using Euler-Bernoulli beam theory. The governing equation and boundary conditions are derived from energy principles. The induced displacements of the theoretical model are presented in order to investigate the performance of the carbon nanotube actuator with different control voltages. The developed model presents invaluable means for designing and predicting the performance of carbon nanotube actuator that can be used in artificial muscle applications.
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Three dimensional laser welding technology for light car body is studied. A robot, a seam tracking system and 4kW CW Nd:YAG laser are used for three dimensional robot laser welding system. The Laser system is used 4kW Nd:YAG laser(HL4006D) of Trumpf and the Robot system is used IRB6400R of ABB. The Seam tracking system is SMRT-20LS of ServoRobot. The welding joint of steel plate are butt and lap joint. The 3-D welding for Non-linear Tailored blank is performed after the observation experiments of bead on plate. Finally, the welding process for non-linear tailored blank and front side member is developed.
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To achieve rapid developments and ensure competitiveness, cost saving, digital manufacturing is essential in die shops. Digital Manufacturing is a technology to facilitate effective product developments and agile productions by digital environments representing the physical and logical schema and the behavior of real manufacturing system including manufacturing resources, processes and products. For applying digital manufacturing to die shop, engineering information managements of products, manufacturing process and resources are needed. In this paper proposes and implements, PLM approach for achieving engineering collaborations in engineering activities. We suggest detail procedures, some examples and considerations of PPR managements in die shop.
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Micron-sized metal wires are widely used in industries such as filtration, catalyst and composite materials, etc. In the wire drawing process, the die that is used conventionally is an effective and, at the same time, sensitive component. However, a typical array of the dies has caused many problems in the wire drawing process, e.g., large frictional force on the interface between wire and the resulting high heat generation, precise adjustment of the dies, extended cooling system, die abrasion, etc.. Because of these problems, there have been many works that are aiming at improving the efficiency of wire drawing process by analyzing the die geometry and by applying advanced die material to prolong the die life or even at developing a dieless wire drawing system. This paper is dealing with developing a new wire drawing system that is applicable to reduce the wire drawing steps with high draw ratio. The new wire drawing system does not use the dies, but use the self-induced heater that works on the basis of the resonant phenomenon of wire material. The electromagnetic wave is the heating source. The results of the study on the diameter reduction and microwave flow analysis show that the heating effectiveness of the wire is influenced by the energy distribution in the microwave propagation chamber. We can obtain diameter-reduced wires by using microwave in the dieless drawing process. Microwave as a heating source is capable of producing wires without applying dies in wire drawing process.
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This paper deals with the algorithm development that inspects defects such as Bright Defect Dots, Dark Defect Dots, and Line Defect caused by the process of LCD(Liquid Crystal Display). While most of LCD production process is automated, the inspection of LCD panel and its appearance depends on manual process. So, the quality of the inspection is affected by the condition of worker. Especially, the more LCD size increases, the more the worker feels fatigued, which causes the probability of miss judgement. So, the automated inspection is required to manage the consistent quality of the product and reduce the production costs. In this paper, to solve these problems, we developed the imaging processing algorithm to inspect the defects in captured image of LCD. Experimental results reveal that we can recognize various types of defect of LCD with good accuracy and high speed.
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This paper describes an intelligent filler wire feeding device which can control 3- dimensional seam tracking and the filler wire speed by measuring the gap position and the joint gap width in laser welding. By means of visual sensor controlled filling the missing material into the joint gap and 3 dimensional seam tracking, lineup errors from manufacturing tolerances and the repeatability of lineup jigs and weld robot can be balanced and at an even seam quality which avoids weld defects. In this paper, we assessed weld quality in 2mm sheets of A16061 which had various gap width by using the intelligent filler wire feeding device.
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The overall goal of this thesis is to develop a new algorithm based on the octree model for geometric and mechanistic milling operation at the same time. Most commercial machining simulators are based on the Z map model, which has several limitations in terms of achieving a high level of precision in five-axis machining simulation. Octree representation being a three-dimensional (3D) decomposition method, an octree-based algorithm is expected to be able to overcome such limitations. With the octree model, storage requirement is reduced. Moreover, recursive subdivision is processed in the boundaries, which reduces useless computations. To achieve a high level of accuracy, fast computation time and less memory consumption, the advanced octree model is suggested. By adopting the supersampling technique of computer graphics, the accuracy can be significantly improved at approximately equal computation time. The proposed algorithm can verify the NC machining process and estimate the material removal volume at the same time.
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Digital Virtual Manufacturing is a technology to facilitate effective product developments and agile productions by digital models representing the physical and logical schema and the behavior of real manufacturing systems including products, process, manufacturing resources and plants. A digital virtual factory as a well-designed and integrated environment is essential for successful applications of this technology. In this research, we constructed a sophisticated digital virtual factory of the shipbuilding company's section steel shop by 3-D CAD and virtual manufacturing simulation. This digital virtual factory can be applied for diverse engineering activities in design, manufacturing and control of the real factory.
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Roll drafting operation causes variations in the linear density of bundles because the bundle flow cannot be controlled completely by roll pairs. Defects occurring in this operation bring about many problems successively in the next processes. In this paper, we attempt to analyze the draft dynamics and the linear density irregularity based on the governing equation of a bundle motion that has been suggested in our previous studies. For analyzing the dynamic characteristics of the roll drafting operation, it is indispensable to investigate a transient state in time domain before the bundle flux reaches a steady state. However, since governing equations of bundle flow consisting of continuity and motion equations turn out to be nonlinear, and coupled between variables, the solutions for a transient state cannot be obtained by an analytical method. Therefore, we use the Finite Difference Method(FDM), particularly, the FTBS(Forward-Time Backward-Space) difference method. Then, the total equations system yields to an algebraic equations system and is solved under given initial and boundary conditions in an iterative fashion. From the simulation results, we confirm that state variables show different behavior in the transient state; e.g., the velocity distribution in the flow field changes more quickly the linear density distribution. During a transient flow in a drafting zone, the output irregularity is influenced differently by the disturbances, e.g., the variation in input bundle thickness, the drafting speed, and the draft ratio.
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This paper presents a survey of software reliability modeling and it's application to pre-built software system combined with hardware such as numerical controller based on personal computer systems. Many a systems in these days are much more becoming software intensive and many software intensive systems are safety critical. For this reason, the technique well developed to measure of software reliability is very important for whom to assess such a system. This paper provides a brief idea of method to evaluate such a system's reliability based on hardware performance.
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Automatic lens assembly system is used for automatically assembling the lens module of phone camera. In this paper, we are trying to develop the cluster type automatic lens assembly with standard tray for applying for assembly field directly. This paper proposes the principle of cluster type lens assembly system and the related assembly production line concept for optimal automatic lens production line.
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In order to manufacture a doubly curved sheet metal effectively, a flexible incremental roll forming process has been developed by adopting the advantages of the incremental forming process and the roll forming process by combining inherent flexibility of the incremental forming process and continuous deformation of the roll forming process. The forming method has been further enhanced to form general quadrilateral blanks (including a square, a rectangle, a symmetrical trapezoid and an asymmetrical trapezoid, etc.) into doubly curved shapes by controlling the forming paths developed by various experiments.
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Digital Manufacturing is a technology to facilitate effective product developments and agile productions by digital environments representing the physical and logical schema and the behavior of real manufacturing system including manufacturing resources, processes and products. A digital virtual factory as a well-designed and integrated environment is essential for successful applications of this technology. In this research, we constructed a sophisticated digital virtual factory by measuring and 3-D CAD modeling using parametric methods. Specific parameters of each objects were decided by object-oriented schema of the digital factory. It is expected that this method is very useful for constructions of a digital factory, and helps to manage diverse information and re-use 3D models.
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Manufacturing companies should perform process planning and its evaluation concurrently with new product developments so that they can be highly competitive in the modern market. Process planners should make decisions in the manner of concurrent and collaborative engineering in order to reduce the manufacturing preparation time and cost when developing new products. Automated generation of analysis models from the integrated database, which contains process and material information, reduces time to prepare analyses and makes the models reliable. In this research, we developed a web-based system for concurrent and collaborative system for production flow analysis, using web, database, and simulation technology. An integrated database is designed to automatically generate analysis models from process and material plans without reworking the data. This system enables process planners to evaluate their decision fast and share their opinions with others easily. With this system, it is possible to save time and cost for assembly process and material planning, and reliability of process plans can be improved
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High speed machining(HSM) technique is widely used in the appliance, automobile part and mold industries, which has many advantages such as good quality, low cost and rapid machining time. but it also has problems like tool break, smooth tool path, and so on. In particular, small size end mill is easy to break, so it must be changed before interrupting operation. Generally, the tool life of small size end mill is effected by the milling conditions whose evaluated parameters are spindle, feedrate, and width of cut. The experiments are carried out by full factorial design of experiments using and orthogonal array. This paper shows optimal combination and mathematical model for tool life, and the analysis of variance(ANOVA) is employed to analyze the main effects and the interactions of these milling parameters and the second-order polynomial regression model with three independent variables is estimated to predict tool life by multiple regression analysis.
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Dynamic job shop environment requires not only more flexible capabilities of a CAPP system but higher utility of the generated process plans. In order to meet the requirements, this paper develops an algorithm that can select machines for the machining operations to be performed by predicting the machine loads. The developed algorithm is based on the multiple objective genetic algorithm that gives rise to a set of optimal solutions (in general, known as Pareto-optimal solutions). The objective shows a combination of the minimization of part movement and the maximization of machine utility balance. The algorithm is characterized by a new and efficient method for nondominated sorting, which can speed up the running time, as well as a method of two stages for genetic operations, which can maintain a diverse set of solutions. The performance of the algorithm is evaluated by comparing with another multiple objective genetic algorithm, called NSGA-II.
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A Robot Performance Evaluation System(RPES) with the laser tracker Leica LTD 500 was developed according to the ISO 9283 robot performance criteria. The developed system is set up a test robot to continuously move the prescribed cyclic trajectories without a human intervention and the laser tracker to simultaneously measure the robot's movement. And then, the system automatically extracts the required data from the tremendous measured data, and computes the various performance criteria which represents the present state of the test robot's performance. This paper explains how ISO 9283 robot performance criteria was used for the developed system, and suggests a automatic data extraction algorithm from the mass of measured data. And also, a user-friendly Robot Performance Evaluation System(RPES) Software was developed with Visual Basic satisfying the need of Hyundai Motor Company. The developed system was implemented on NACHI 8608 AM 11 robot. The resulted output shows the effectiveness of the developed system.
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This paper presents requirements of home network protocol for home netowkr system. Home network protocol is designed to satisfy the above requirements on the assumption that it has to be implemented by software on the microprocessors generally used in household appliances. And, we execute a qualitative comparison to other protocols such as CEBus, LonWorks and LnCP.
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This paper proposes an effective algorithm, P-DCF(Polling DCF) to satisfy real-time requirements in the industrial environments, based on 802.11 DCF protocols. Theoretical analysis and actual experiments are carried out, which shows that the proposed P-DCF brings several benefits: 1) it reduces the time delay for frame transmission 2)it guarantees bounded upper limit of maximum transmission delay 3) it maintains fairness
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A new MR cylinder with built-in valves using MR fluid (MR valve) is suggested and fabricated for fluid control systems. The MR fluid is a newly developed functional fluid whose obvious viscosity is controlled by the applied magnetic field intensity. The MR cylinder is composed of cylinder with small clearance and piston with electromagnet. The differential pressure is controlled by the applied magnetic field intensity. It has the characteristics of simple, compact and reliable structure. The size of MR cylinder and piston has
${\varphi}30mm{\times}300mm\;and\;{\varphi}28.5mm{\times}120mm$ in face size, respectively and 0.8mm in gap length. Through experiments, it was found that the differential pressure is controlled by the applied magnetic field intensity under little influence of the flow rate, which corresponds to a pressure control valve. The differential pressure of 0.47MPa and contact force of 320N were obtained with the input current of 1.5A. The rising time of force was 1.1s in step response of a manipulator using the MR cylinder. The effectiveness of the MR cylinder was also demonstrated through the force control. -
This paper describes the performance index of mobile robot and development of testbed which is used to evaluate the index. The developed testbed has rectangular structure similar to a living room of home. It is semi-automation testbed system for evaluation of cleaning performance index. This system is composed with scattering and cleaning equipment of test materials, equipment rifting of objects in inner space and sides itself, vision processing system. To be consistent of performance evaluation of cleaning robot, we make use of camera in this system for the sake of measurement of robot s mobility, path and suction quantity.
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Robot is composed of various devices but, those are incompatible with each other and hardly developing reusable control software. We suggest standard abstract interface for robot software component to make portable device and reusable control software of robot. This assures uniform abstracted interface to the device driver software like sensor and actuator and, control program can be transparent operation over device. We can develop devices and control software separately and independently with this idea. This makes it possible to replace existing devices with new devices which have a improved performance.
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SALM(Simultaneous localization and mapping) and AI(Artificial intelligence) have been active research areas in robotics for two decades. In particular, localization is one of the most important tasks in mobile robot research. Until now expensive sensors such as a laser sensor have been used for mobile robot localization. Currently, the proliferation of RFID technology is advancing rapidly, while RFID reader devices, antennas and tags are becoming increasingly smaller and cheaper. So, in this paper, the smart floor using passive RFID tags is proposed and, passive RFID tags are mainly used for identifying location of the mobile robot in the smart floor. We discuss a number of challenges related to this approach, such as tag distribution (density and structure), typing and clustering. In the smart floor using RFID tags, the localization error results from the sensing area of the RFID reader, because the reader just knows whether the tag is in the sensing range of the sensor and, until now, there is no study to estimate the heading of mobile robot using RFID tags. So, in this paper, two algorithms are suggested to. The Markov localization method is used to reduce the location(X,Y) error and the Kalman Filter method is used to estimate the heading(
$\theta$ ) of mobile robot. The algorithms which are based on Markov localization require high computing power, so we suggest fast Markov localization algorithm. Finally we applied these algorithms our personal robot CMR-P3. And we show the possibility of our probability approach using the cheap sensors such as odometers and RFID tags for mobile robot localization in the smart floor -
This paper presents a method for the robot localization and calibration using the ultrasonic and the radio frequency. The distance between the receiver and a beacon can be computed by using the difference between times of flight. The presented method uses the gradient of the maximum amplitude of the ultrasonic in order to measure the time of flight precisely. The measured three distances between the receiver and the beacon are used to compute the robot position by the direct inverse method and the iterated least square approximation method. This paper is defined the calibration as the problem to find the location of 3 beacons and 3 robots, and presents 3 methods for it and found the 2B2R method as the best among them.
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In this paper, the dynamic crawling of a five-bar planar mechanism is investigated. One complete cycle of the crawling selected in this study consists of four different steps, i) sliding at one contact point between the mechanism and the ground, ii) changing its configuration without sliding at two contact points, iii) sliding at the other contact point, and iv) again changing its configuration without sliding at two contact points. In this type of crawling, the crawling mechanism maintains the shape of the parallel structure throughout a complete crawling cycle. The modeling algorithm for serial manipulators proposed by M. Thomas and et al.[1] is employed by introducing imaginary joints and links which represent the contact interfaces between the one end of the mechanism and the ground, while the other end of the mechanism is regarded as an end-effector of the imaginary serial manipulator which treats the reaction force and torque at the contact point as external forces. Then, a complete cycle of dynamic crawling of the mechanism is investigated through various computer simulations. The simulation result show that the stable crawling characteristics of the mechanism could be secured when the proper configurations depending on specified frictional constraints are met.
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There is no agreed definition of intelligence. The ability to adapt to the environments is a kind of intelligence. Expert functionally recognize environment using their five senses, and acquire and memorize knowledge necessary for operating machines. Knowledge that they cannot acquire directly is acquired in indirect ways. The purpose of intelligence machines is applying to machines experts' knowledge acquisition process and their skills in operating machine. An agent is an autonomous process that recognizes external environment, exchanges knowledge with external machines and performs an autonomous decision-making function in order to achieve common goals. This paper describes agent application for intelligence machine.
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To support the expansion of the autonomous robot market, the establishment of evaluation standards of the robot performance are essential. In this paper, to venture the standardization of the performance evaluation of the autonomous robot, the authors take the autonomous cleaning robot(ACR) as the initial stepping stone. Recently, the ACR has been being developed and marketed actively in many countries including Korea and it believes to be the fore-runner among various types of autonomous robot products. Standards of the performance evaluation for the ACR could be easily modified and applied to other autonomous robots. This paper formulates and suggests a group of standards for the performance evaluation based on a evaluation platform for the ACR. The newly developed performance evaluation platform has been designed to include all the important aspects of living environments in reality. In the platform the performance of the ACR is measured in terms of mobility, cleaning performance, avoidance of obstruction(safety), and operation noise. A few commercially available ACR products are collected and tested in the evaluation platform and compared against the performance evaluation standards formulated.
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This paper attempts to derive and analyze the dynamic system of pinching a rigid object by means of two multi-degrees-of-freedom robot fingers with soft and deformable tips. It is shown firstly that a set of differential equation describing dynamics system of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. It is shown secondly that the problems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. In this paper, the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation that the control system gives the performance improvement in the dynamic stable grasping of the dual fingers robot with soft tips.
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Development of a locomotive mechanism for the capsule type endoscopes will largely enhance the ability to diagnose disease of digestive organs. In connection with it, most of the researches have focused on an installable locomotive mechanism in the capsule. In this paper, it is introduced that the movement of a capsule type endoscope in digestive organ can be manipulated by magnetic force produced outside human body. Since the magnetic force is provided by permanent magnets, no additional power supply to the capsule is required. Using a robotic manipulator for locating the external magnet, the capsule motion control system can cover the whole human digestive organs. This study is particularly concentrated on dither motion effect to improve the mobility of capsule type endoscope. It was experimentally found out that the friction coefficient between the capsule and digestive organ can be remarkably reduced by superposing yawing or rolling dither motion on the translatory motion. In this paper, the experimental results obtained while the direction, amplitude and frequency of sinusoidal dither motion were changed are reported.
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In precision positioning applications, such as scanning tunneling microscopy and diamond turning machines [1], it is often required that actuators have nanometer resolution in displacement, high stiffness, and fast frequency response. These requirements are met by the use of piezoceramic actuators. A major limitation of piezoceramic actuators, however, is their lack of accuracy due to hysteresis nonlinearity and drift. The maximum error due to hysteresis can be as much as 10-15% of the path covered if the actuators are run in an open-loop fashion. Hence, the accurate control of piezoceramic actuators requires a control strategy that incorporates some form of compensation for the hysteresis. One approach is to develop an accurate model of the hysteresis and the use the inverse as a compensator. The Preisach model has frequently been employed as a nonlinear model for representing the hysteresis, because it encompasses the basic features of the hysteresis phenomena in a conceptually simple and mathematically elegant way. In this paper, a new numerical inversion scheme of the Preisach model is developed with an aim of compensating hysteresis in piezoceramic actuators. The inversion scheme is implemented using the first-order reversal functions and is presented in a recursive form. The inverted model is then incorporated in an open-loop control strategy that regulates the piezoceramic actuator and compensates for hysteretic effects. Experimental results demonstrate satisfactory regulation of the position of the piezoceramic actuator to the desired trajectories.
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This paper deals with the algorithm development that inspects defects such as Lens Focus, Focus check, Black Defect, Dark Defect, Dim Defect, Color Defect, and Line Defect, Angle Defect, IrisAgc Defect caused by the process of 2M Class Compact Camera Module (CCM). Domestic market was majorly comprised of VGA(0.3 million pixel) market. But in the middle of year 2004, camera phone with Mega Pixel has appeared, and it is estimated that the camera phone with Mega Pixel will take up to 28% of total phone sales if it is released in the end of year 2004. Since the inspection of finished products is done manually, it is major obstacle in production increment In this paper, to solve these problems, we developed the imaging processing algorithm to inspect the defects in captured image of assembled CCM. The performances of the developed inspection system and we can recognize various types of defect of CCM modules with good accuracy and high speed
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Light scattering measurement system that can evaluate light scattering characteristic from defects on silicon wafer surface has been developed. The system uses
$Ar^+$ laser as an illumination source, and a highly sensitive photomultiplier tube (PMT) for detecting scattered light from defects. Unlike with conventional measurement system, our system has ability to measure scattered light pattern from wide range of scattering angles with changeable incidence condition. It is shown that our developed system is effective to discriminate the types and sizes of defects from basic experimental results using a microscatch and a PSL sphere. -
In precision machinery systems for medical and chemical applications, micropumps with a low pulsation have been demanded and investigated for accurate delivery of a small amount of liquid. This study proposes sheet type check valves instead of ball type check valves for PZT pumps and performs some tests on dynamics characteristics of check valves having different design parameter with variable frequency. The selected materials of check valves is NBR, PP film, Polyimide and Stainless steel(SUS304). In the experiment, dynamic characteristics of stainless steel thin plate have better performance than others.
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This paper formulates the parameter estimation of cornering behavior of a vehicle. Especially some vehicle parameter is very important on stability control of chassis by ECU, but some parameter is so hard to get by sensor which parameter is included the nonlinear characteristic of tire cornering force. So we need to deduce that parameter from used signal and numerical method. In this study, we propose a estimation method and present the simulation by parameter estimation technique.
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Most electronic chassis control systems until today have been designed with optimization on its own performance. However, According to the increase of the interest regarding a vehicle safety and development of information technique, the integration technique of current chassis systems is being emphasized. Each enterprise proposed it with name of GCC(Global Chassis Control) or UCC(Unified Chassis Control). This study realizes control algorithm of suspension and brake by using the vehicle model of low degree of freedom as the primary stage of realization of integrated chassis control system. The proposed algorithm build the simulation environment connected to the CarSim having full vehicle model of 27 degree of freedom for raising the thrust of results
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In this paper, a new visual servo method, which uses 5 axis picomotor to compensate the misalignment generated between a SLM and a CCD in a holographic storage device, was proposed and the effectiveness of it was proved by the experiment. In a holographic storage device, the data processing is done by the SLM and the CCD, and the shape of data is 2 dimensional binary patterns. Therefore, the exact image matching between the SLM and the CCD is very important, and the mismatching of it causes the errors in the data reconstruction. First, the brief introduction of a holographic data storage is given, then, BER concept which is errors caused by pixel mismatch between the SLM and the CCD is defined. Second, the geometric relation between 5 axis picomotor and the CCD movement is studied. Finally, the visual servo method using 5 axis picomotor to reduce the BER in a holographic storage device is proposed and experimented. From the experiment, we find that about 3% BER improvement is obtained by the proposed method.
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The research and development for LPLI system to replace the conventional LPG fuel supply system has been processed with a view to enhancing the environmental status and the efficiency for LPG cars. Part of the small sized cars are under commercialization with the LPLI application already. And yet, most of the technologies are relied upon the advanced countries and as part of the application for large scaled engines, many researches are on the increase. This study shows the technology development to make use of LPLI system for those large engines and reviews the controllers, which were manipulated through experiments for their work, reliability and possibility for commercialization.
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The running condition of multi-system air conditioner is prone to vary largely as it is designed for individual conditioning in each space of middle and small sized buildings. This leads to overcooling in case of partial load run, while the lack of capacity happens in case of full load run. Besides these, there exist such problems as instabilities due to the uneven refrigerant distribution caused by fluctuation of load and the change in piping line. Based upon the basic study on the function characteristics found in parts needed for maximized system working design in order to troubleshoot, the system functioning pattern should be identified through the different tests with various operating circumstances and the analysis models should be developed. With this ground, the control logic has to be made to have a control over capacity and make possible the efficient distribution of refrigerant.
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The paper proposes the elastic modulus evaluation technique of a cantilever beam by vibration analysis based on time-average electronic speckle pattern interferometry (TA-ESPI) with non-contact and nondestructive and Euler-Bernoulli equation. General approaches for the measurement of elastic modulus of thin film are Nano indentation test, Bulge test and Micro-tensile test and so on. They each have strength and weakness in the preparation of test specimen and the analysis of experimental result. ESPI has been developed as a common measurement method for vibration mode visualization and surface displacement. Whole-field vibration mode shape (surface displacement distribution) at a resonance frequency can be visualized by ESPI. And the maximum surface displacement distribution from ESPI is a clue to find the resonance frequency at each vibration mode shape. And the elastic modules of test material can be easily estimated from the measured resonance frequency and Euler-Bernoulli equation. The TA-ESPI vibration analysis technique is able to give the elastic modulus of materials through the simple processing of preparation and analysis.
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We reviewed controllers with a time delay estimation in this paper. Time delay control (TDC) and sliding mode control (SMC) are well known robust control schemes. Basically, the TDC has a main characteristic called a time delay estimation from which we can estimate the total uncertainty of a system. . The TDC causes the stick-slip in the case of systems with a friction. The so-called TDCSA which are short for TDC with switching action was developed to reduce the stick-slip. The TDC has the additional switching action term in the TDC structure. In the other hand, the SMC dose not have a time delay estimation but instead it can estimate the system uncertainty through the switching action. The SMC has a difficulty to estimate the total uncertainty of a system because it does not have a time delay estimation. In order to solve the difficulty, some control schemes were developed. Among them, we need to focus our attention on two control schemes: SMCPE and SMCTE, which are short for sliding mode control with a perturbation estimation and sliding mode control with a time delay estimation, respectively. In this paper, we analyzed and compared the characteristic of above three controllers. Even though the motives for the development of three control schemes are different, three control schemes have much in common in terms of their controller structures.
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This paper presents a method for inter-sheet spacing control in a flexible media handling device. In order to verify the performance of inter-sheet spacing control by experiment, system of section structure is introduced in the first place. In the introduced system, each section is driven by different servo motor for independent section freedom. And suitable inter-sheet spacing control algorithm that is more optimal than conventional inter-sheet spacing control algorithm is proposed. Finally experiments are performed to confirm the performance of inter-sheet spacing control. And two inter-sheet spacing control algorithms, conventional and proposed, are compared with each other.
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Since human is vulnerable to emotional, physical and environmental distractions, most human inspectors cannot sustain a consistent 8-hour inspection in a day specifically for small components like door locking levers. As an alternative for human inspection, presented in this study is the development of a machine vision inspection system (MVIS) purposely for door locking levers. Comprises the development is the structure of the MVIS components, designed to meet the demands, features and specifications of door locking lever manufacturing companies in increasing their production throughput upon keeping the quality assured. This computer-based MVIS is designed to perform quality measures of detecting missing portions and defects like burr on every door locking lever. NI Vision Builder software for Automatic Inspection (AI) is found to be the optimum solution in configuring the needed quality measures. The proposed software has measurement techniques such as edge detecting and pattern-matching which are capable of gauging, detecting missing portion and checking alignment. Furthermore, this study exemplifies the incorporation of the optimized NI Builder inspection environment to the pre-inspection and post-inspection subsystems.
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As alternative materials for bipolar plate of PEM Fuel Cells, carbon composites were fabricated by compression molding. In this study, four types of nano particles, such as Carbon nanotubes, Carbon black, GX-15 and P-15 were mixed with epoxy resin to provide electric conductivity and structural properties. By increasing pressure during molding and volume ratio of nano particles, the physical contact among particles was improved resulting in increased electric conductivity. Surface resistance test showed, P-15 particles have the highest electric conductivity.
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A plastic-based CE (capillary electrophoresis) microchip was fabricated by hot embossing process. A Si mold was made by wet etching process and a PMMA wafer was cut off from 1mm thick PMMA sheet. A micro-channel structure on PMMA substrate was produced by hot embossing process using the Si mold and the PMMA wafer. A vacuum assisted thermal bonding procedure was employed to seal an imprinted PMMA wafer and a blank PMMA wafer. The results of microscopic cross sectional images showed dimensions of channels were well preserved during thermal bonding process. In our procedure, the deformation amount of bonding process was below 1%. The entire fabrication process may be very useful for plastic based microchip systems.
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The aim of this paper is to investigate the effect of surface texturing on metal surface and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 is recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.
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The size effects for adhesive and frictional characteristics were studied. The specimen was Mica and the AFM tips were SiO2. The radii of SiO2 tip were 280, 380, 930, and 2230 nm on which tribological tests had never been performed. It was found that the adhesive forces and the frictional coefficients increased non-linearly with tip radius. Compared with previous studies at nanoscale and microscale, the results showed behaviors bridging each previous result. It could be said that these results were clues to explain the material behaviors between nanoscale and microscale both in adhesion and friction.
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Micro-stereolithography is a newly proposed technology as a means that can fabricate a 3D micro structure of free form. It makes a 3D micro-structure by dividing the shape into many slices of relevant thickness along horizontal surfaces, hardening each layer of slice with a focused laser beam, and stacking them up to a desired shape. However, we do not anticipate the electric conductivity of the final product at the existing micro-stereolithography. The reason is that this technology uses polymer to make the product. Thus the new suspension which was mixed conventional photopolymer with metal powder was developed in this study. The developed suspensions were based on SL5180 which is commercialized resin and IMS03 that is made in our laboratory. And Triton X-100 was added at the suspension for getting the scattering effect and stabilizing effect. The layer recoating device was developed to be flat the mixed high viscosity suspension. A 3D micro structure was manufactured by using recoating system and micro-stereolithography system. The fabricated product was sintered to get the electric conductivity. After sintering, a pure copper product was made. In this study, new process was developed by making metal micro structure having an electric conductivity. This technology broadened the realm of the micro-stereolithography technology. And it will be applied to make the 3D micro structure of free form which has a high hardness and an electric conductivity in the near future.
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The Sonication method is widely used with surfactants to suspend individual single walled nanotubes in solution, and it is well known that sonication-induced tube cutting occurs. Recently, it is found out that ultrasonicated nanotubes yield simultaneous separation by tube length and diameter. Nanotubes that have been cut shortest possess the greatest enrichments of large-diameter species. In this study, we cut single walled carbon nanotubes using a ball milling method and find out similar behavior compared to the sonication process Cutting mechanisms are also investigated using continuum approaches.
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This paper is about the carbon nanotube(CNT) samples called as CNT cartridges. The CNT cartridges are useful to make it better to fabricate the nano-sized devices like nanoprobes and nanotweezers through physical attachment. To make these cartridges, we need to align CNTs and to purify them from raw material. There is a variety of methods to align 1-dimensional nanostructures like nanotubes and nanowires. In this review, we mainly focused on the methods using electric field. And we will introduce various researches in relation to the CNT cartridges and the fabrication methods using the CNT cartridges and nanomanipulation techniques.
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Nanoimprint Lithography(NIL) has increasingly been recognized as a key manufacturing technology for nanosized feature. One of the most important task for nanoimprint lithography is to provide the imprinting stamp with low price. The Stamp fabricated with Si based material by e-beam lithography, RIE is extremely expensive and its throughput is very limited and PDMS replica is too soft to hold high imprinting pressure.(>5atm) In this study, we present the imprinting stamp which can be easily replicated from original mold and is based on PVC film. Replication of original Si mold to PVC film was done by Hot embossing technique, (
$120^{\circ}C$ of Temperature, 20 atm applied) As small as 100nm patterns were successfully transferred into PVC film. The size of stamp was up to 100mm in diameter. -
Manufacturing capability at the micro or nano scale production field is requested strongly in view of parts and product miniaturization. Miniaturized parts and products will introduce lots of benefits in terms of high precision functionality and low energy consumption. This paper presents the results of micro milling machine tool development for micro machining process. Finite element analysis has been performed to know the relationship between design dimensional variables and structural stiffness in terms of static, dynamic, thermal aspects. Performance evaluation through machining has been tested and discussed for achievable machining characteristics.
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Brittle materials, especially single-crystal silicon wafer, are widely used for sensors, IC industry, and MEMS applications. e general machining process of crack easy materials is by chemical agents, but it is hazardous and time consuming. Also, it is difficult to get high aspect ratio micro structure. As an alternative tool, an AJM(Abrasive jet machining) is promising method in terms of high aspect ratio and production cost. In this study, to get more precise detail compared to general AJM, photo polymer mask, SU-8, used in photolithography was applied in AJM. Process parameters such as abrasive diameter, air pressure, nozzle diameter, flow rate of abrasive in AJM and a variety of conditions in spin coating were decided. Finally, micro channel and mixer was fabricated to see the efficiency of the AJM with photo polymer mask.
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3D micro scaled shapes are fabricated with the method of direct writing and superposing grooving in ambient air using femto-second laser pulses and copper, aiming at establishing an industrially useful femto-second laser processing machine to be able to fabricate three dimensional micro-scale structures, especially micro scaled molds, and processing techniques. For the several advantages, there is no thermally influenced region around the area irradiated by the laser beam and surfaces irradiated laser beam are smooth and substances ablated to form are no attached on the surface of works and so on, the femto-second laser technology is anticipated for advanced micro/nano precision technology.
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Microstereolithography has evolved from the stereolithography technique, and is also based on a light-induced layer-stacking manufacturing. Integral microstereolithography is proposed for building a 3D microstructure rapidly, which allows the manufacture of a complete layer by one irradiation only. In this study, we developed the integral microstereolithography apparatus based on the use of
$DMD^{TM}$ as dynamic pattern generator. It is composed of Xenon-Mercury lamp, optical devices, pattern generator, precision stage, controllers and the control program. Also, we estimated curing characteristics in photopolymer. The relationship between the viscosity of diluent-oligomer solutions and curing width, irradiation time and curing property has been studied. -
Focused Ion Beam machining is an attractive approach to produce nano-scale 3D structures. However, like other beam-based manufacturing processes, the redeposition of the sputtered material during the machining deteriorates the geometric accuracy of ion beam machining. In this research a new approach to reduce the geometric error in FIB machining is introduced. The observed redeposition phenomena have been compared with existing theoretical model. Although the redeposition effect has good repeatability the prediction of exact amount of geometric error in ion beam machining is difficult. Therefore, proposed method utilizes process control approach. Developed algorithm measures the redeposition amount after every production cycle and modifies next process plan. The method has been implemented to a real FIB machine and the experimental results demonstrated considerable improvement of five micrometer-sized pocket machining.
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In recent years, as the demands of VBNS and VDSL increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM elements increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the optical alignment characteristics of multi-axis ultra precision stage were studied. The alignment algorithms were studied for applying to the ultra precision multi-axis stage. The alignment algorithm is comprised of field search and peak search algorithms. The contour of optical power signals can be obtained by field search and the precise coordinate can be found out by peak search. Two kinds of alignments, such as 1 ch. input vs. 1 ch. output optical stack, and 1 ch. input vs. 8 ch. output PLC stacks were performed for investigating the alignment characteristics.
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Micro nozzle is employed as a dynamic passive valve in micro fluidic devices. Micro nozzle array is used in micro droplet generation in bio-medical applications and propulsion device for actuating satellite and aerospace ship in vacuum environments. Aperture angle and the channel length of the micro nozzle affect its retification efficiency, and thus it is needed to produce micro nozzle precisely. MEMS process has a limit on making a micro nozzle with high-aspect ratio. Reactive ion etching process can make high-aspect ratio structure, but it is difficult to make the complex shape. Focused ion beam deposition has advantage in machining of three-dimensional complex structures of sub-micron size. Moreover, it is possible to monitor machining process and to correct defected part at simultaneously. In this study, focused ion beam deposition was applied to micro nozzle production.
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A new foxtail actuator driven by V-shape beam deflection using electrostatic force has been designed, fabricated and characterized for nano-resolution manipulators. The proposed foxtail mechanism was implemented using a pair of electrostatic actuators and a pair of holding actuators, which was analyzed based on the electromechanically coupled motion of voltage - displacement relation. The proposed actuator was fabricated onto Silicon-on-Insulator (SOI) wafer and its stepping characteristics were measured by micro optical interferometer consisting of integrated micromirror and optical fiber. The fabricated foxtail microactuator was successfully operated from 1nm to 76nm, and the magnitude of step displacement was controllable up from 26nm/cycles to 53nm/cycle by changing the voltage.
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Micro hole is one of basic elements for micro device or micro parts. By micro ECM, micro holes less than
$50\mu{m}$ in diameter can be machined easily. Machining characteristics of micro ECM were investigated according to machining conditions such as electrolyte concentration and pulse conditions. From the investigation, optimal machining conditions were suggested for micro ECM of stainless steel. For the micro machining with high resolution, the change of machining gap should be predicted. By using electrochemical principle equations, the change of machining gap was simulated. -
In recent, injection molding process for features in sub-micron scale is under active development as patterning nano-scale features, which can provide the master or stamp for molding, and becomes available around the world. Injection molding has been one of the most efficient processes for mass production of the plastic product, and this process is already applied to nano-technology products successfully such as optical storage media like DVD or BD which is a large area plastic thin substrate with nano-scale features on its surface. Bio chip for like DNA sequencing may be another application of this plastic substrate. The DNA can be sequenced using order of 100 nm pore structure when making the DNA flow through the pore structure. Agarose gel and silicon based chip have been used to sequence the DNA, but injection molded plastic chip may have benefit in terms of cost. This plastic DNA sequencing chip has plenty of pillars in order of 100 nm in diameter on the substrate. When the usual features in case of DVD or BD have very low aspect ratio, even less than 0.5, but the DNA chip will have relatively high aspect ratio of about 2. It is not easy to injection mold the large area thin substrate with sub-micron features on its surface due to the characteristics of the molding process and it becomes much more difficult when the aspect ratio of the features becomes high. We investigated the effect of the molding parameters for injection molding with high aspect ratio nano-scale features and injection molded some plastic DNA sequencing chips. We also fabricated PR masters and Ni stamps of the DNA chip to be used for molding
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Micro heat flux sensor is used in various industries to measure heat flux. In this study, a micro heat flux sensor is fabricated using the MEMS (Micro Electro Mechanical Systems) techniques. The fabricated sensor is composed in thermopile for sensor and SU-8 for thermal resistance layer. The new method of fabrication SU-8 is proposed in this study. The sensitivity is
$44\;\mu{V/(W/cm^2)}$ at steady state and Reynolds number is 91322. -
As demands for precision parts are increased, existing methods to fabricate them such as MEMS, LIGA technology have the technical limitations like high precision, high functionality and ultra miniaturization. A micro-stereolithography technology based on
$DMD^{TM}$ (Digital Micromirror Device) can meet these demands. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D part is fabricated by stacking layers that are sliced as 2D section from STL file. Whereas in conventional method, the resin surface is cured as scanning laser beam spot according to the section shape, but in this research, we use integral process which enables to cure the resin surface at one time. In this paper, we deal with the dynamic pattern generation and$DMD^{TM}$ operation to fabricate micro structures. Firstly, we address effective slicing method of STL file, conversion to bitmap, and dynamic pattern generation. Secondly, we suggest$DMD^{TM}$ operation and optimal support manufacturing for$DMD^{TM}$ mounting. Thirdly, we examine the problems on continuous stacking layers, and their improvements in software aspects. -
As the optical communication is introduced to the backbone network at first and becomes a general communication method of network, the demand of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM(Wavelength Division Multiplexing) element increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the driving mechanism of ultra precision stage is studied with the aim of optimal design of stage. The travel and the resolution of stage are investigated. The hysteresis of the stage is generated because of PZT actuator. The hysteresis and the inverse hysteresis are modeled in X, Y, and Z-axis motion. The input data of desired displacement to the stage according to input voltage is obtained from the inverse hysteresis equation. In the result of experiments with the input data, the errors due to hysteresis are well compensated.
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Fine microgroove is the key component to fabricate micro-grating, micro-grating lens and so on. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. This study deals with the creation of ultra-precision micro grooves using non-rotational diamond tool and CNC machining center. The shaping type machining method proposed in the study allows to produce V-shaped grooves of
$40\mu{m}$ in depth with enough dimensional accuracy and surface. For the analysis of machining characteristics in micro V-grooving, three components of cutting forces and AE signal are measured and processed. Experimental results showed that large amplitude of cutting forces and AE appeared at the beginning of every cutting path, and cutting forces had a linear relation with the cross-sectional area of uncut chip thickness. From the results of this study, proposed micro V-grooving technique could be successfully applied to forming the precise optical parts like prism patterns on light guide panel of TFT-LCD. -
This paper reports about the development of scanning probe microscopy (SPM) tip with multi-walled carbon nanotube (MWNT). For making a carbon nanotube (CNT) modified tips, AC electric field which causes the dielectrophoresis was used for alignment and deposition of CNTs to the metal coated SPM tip. By dropping the MWNT solution and applying an electric field between an SPM tip and an electrode, MWNTs which were dispersed into a diluted solution were directly assembled onto the apex of the SPM tips due to the attraction by the dielectrophoretic force. In this paper, we investigate experimental conditions about the alignment of the CNT to tip axis according to the change of the angle between a tip and an electrode. Experimental results are presented, and then fabricated CNT tips are showed and measurement results for 15nm gold particles are compared with that of the conventional silicon tip.
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In recent years, as the robot technology is developed the researches on the artificial muscle actuator that enable robot to move dextrously like biological organ become active. The widely used materials for artificial muscle are the shape memory alloy and the electroactive polymer. These actuators have the higher energy density than the electromechanical actuator such as motor. However, there are some drawbacks for actuator. SMA has the hysterical dynamic characteristics. In this paper the segmented binary control for reducing the hysteresis of SMA is proposed and the simulation of anthropomorphic robotic hand is performed using ADAMS.
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Aligned carbon nanotubes(CNTs) array were synthesized using DC plasma-enhanced chemical vapor deposition. Silicon substrate Ni-coated of 5nm thickness were pretreated by
$NH_3$ gas with a flow rate of 180sccm, for 10min. CNTs were grown on the pretreated substrates at$30%\;C_2H_2:NH_3$ flow ratios for 10min. Carbon nanotubes with diameters from 60 to 80 nanometers and lengths about 2.7 micrometers were obtained. Vertical alignment of carbon nanotubes were observed by FESEM. -
The wrinkling in the flange and wall of a part is a predominant failure mode in stamping of sheet metal parts. In many cases this wrinkling may be eliminated by appropriate control of the blank holding force(BHF), but BHF affects the draw depth. Gotoh had studied the wrinkles under
$20{\mu}$ in height. In general, the height of wrinkles could be limited under$200{\mu}$ practically. Therefore small BHF can be allowed so that the depth of drawing could be increased. This paper represents the variation of the wrinkles of flange in the part of cup drawing by using aluminium alloy A1050 and A5052. This simulation is used by the explicit finite elements code$PAM-STAMP^{TM}$ . The computed results are compared with the experimental results to show the validity of the analysis. -
The material removal mechanism of Electrical Discharge Machining (EDM) process has been studied for several decades. However, understanding of the material removal mechanism is still a difficult problem because the mechanism involves complicated physical phenomena including plasma. Especially, for a micro-EDM process, due to the influence of the debris that is generated during the machining process, quantitative modeling of EDM becomes more complex. To understand better the effects of the debris in the micro-EDM process experimentally, a new approach has been introduced in this study. Using a specially designed workpiece holder, the debris generated during the EDM with various process conditions has been collected. Then, using a simulated environment using micro-sized metal powders, the influence of the debris during the single EDM discharge has been observed. The effects of EDM process parameters on the debris size and product quality are discussed.
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Mold-manufacturing process consists of machining and finishing process that are strongly related in each other. But there are few studies about mold-manufacturing process to control those two processes simultaneously. Especially, runout distorts the machined surface from expected so it changes the finishing process and mold-manufacturing time. In this work, basic analyses and experiments were carried out to study RVAS variation according to runout in HSM. To perform those analyses, firstly surface generation analysis was done including runout in ball end milling and then the RVAS that could relate machining and finishing process was proposed. And the optimal finishing process in HSM according to RVAS was also proposed. Through experiment runout occurrence and above analyses were verified.
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An Experiment was carried out to study burr minimization in drilling on the inclined exit surface. Several different drills, exit surface angles and cutting conditions were selected to determine their influences on burr formation. In drilling operation, there are not only flat exit surfaces but also inclined exit surfaces which is described as inclination angle. Inclination of exit surface causes a quiet different burr formation when comparing with flat surface. Burr formation mechanisms are analyzed according to the drill geometries and cutting conditions. Several schemes for burr minimization on inclined exit surface were proposed. Burr geometry in each drill and cutting condition are measured by laser measurement system.
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Grinding process has unique characteristics compared with other machining processes. The cutting edges of the grinding wheel don't have uniformity and act differently on the workpiece at each grinding. The response surface analysis is one of various methods for optimizing and evaluating the process parameters to achieve the desired output. In this study, the effect of the grinding parameters on outcomes of the surface grinding was analyzed experimently. To predict the grinding outcomes and to select the grinding conditions before grinding, the second-order response surface models for the grinding force and the surface roughness were developed.
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Recently, as researches and developments for milli-structure and micro machine are actively progressing, manufacturing technologies and skills for tiny small machine parts are getting more important. So, we have been trying to cut using high revolution air bearing spindle and micro-endmill, and studying for magnitude of cutting force, cutting force wave form and surface roughness. We figured out that in 60,000rpm is so slow that cutting is not perfact. Chatter occured to
$2\mu{m}/rev\;at\;80,000rpm\;and\;4.4\mu{m}/rev$ at 100,000rpm. We confirmed that spindle run out increased surface roughness at high revolution. -
Due to the increase of the need for reliable high density information storage devices, the demand for precise machining of the slider in HDD is rapidly growing. The present fabrication process of slider bears some serious problems such as low yield ratio in mass production, which is mainly caused by inefficient machining processes in shaping camber and crown on the slider. In order to increase slider yield ratio in HDD, a new systematic machining process is proposed and developed in this work. This new machining process includes the use of magnetorheological (MR) fluid, a smart polishing material generally used for ultra-fine surface finishing of micro structures. It is shown that the process proposed in this work enables to make camber and crown pattern in the scale of few tens of nanometers. Experiment results shows that the MR polishing can be also used for shaping process of micro structures.
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Sandwich structures, which are composed of thick core between two thin faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. In this research, we have investigated the embossing configuration at the sheet metal shape through research with regard to the construction that the hardness and stiffness are excellent, and formability is advantage as inner structure. Through the FLD analysis according to the pattern changes, we have confirmed the forming possibility and variation of the aspect thickness. Also, we have fabricated the embossing press mold according to the pattern changes, and obtained the embossing inner structure the forming experiments.
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A displacement magnification mechanism is usually employed in a nano-positioning stage to achieve a large stage motion. A lever mechanism is the most widely used displacement magnifying mechanism. For more large stage motion, double or multiple lever mechanisms can be used. In this case, a more accurate analysis model is needed. This study proposes a more reasonable analysis model for a multiple lever mechanism based on the single lever mechanism model. This paper describes that the high equivalent stiffness of the lever is the most important factor reducing the magnification ratio of the lever mechanism through increasing the deflection of the link and including the axial displacement of the pivot.
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A high-aspect-ratio and high-resolution stainless steel shadow mask for organic thin-film transistors (OTFTs) circuit has been fabricated by a new method which combines photochemical machining, micro-electrical discharge machining (micro-EDM), and electrochemical etching (ECE). First, connection lines and source-drain holes are roughly machined by photochemical etching, and then the part of source and drain holes is finished by the combination of micro-EDM and ECE processes. Using this method a
$100\;\mu{m}$ thick stainless steel (AISI 304) shadow mask for inverter can be fabricated with the channel length of$30\;\mu{m}\;and\;10\;\mu{m}\;respectively.\;The\;width\;of\;connection line\;is\;150\;\mu{m}$ . The aspect ratio of the wall is about 5 and 15, respectively. Metal lines and source-drain electrodes of OTFTs were successfully deposited through the fabricated shadow mask. -
In the micro electrochemical machining (ECM), unfavorable oxide/passive layer formation and overall corrosion of electrodes must be prevented. Generally, the stainless steel electrode corrodes, passivates or dissolves in the electrochemical cell according to the electrode potential. Therefore, the electrode must maintain stable potential. The stable electrode potentials of tool and workpiece were determined with the potentiodynamic polarization test and verified experimentally from the point of machining stability and machined surface quality.
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Screw rotors, the key parts of screw compressors, are used in compressing air and refrigerant due to their high productivity, compact size, low noise and maintenance. In general, a screw compressor is composed of a pair of rotors of complex geometric shape. The manufacturing cost of the screw rotors is high because the complicated helical shapes of the screw rotors are manufactured usually by the dedicated machine tools. In this study, rotor profile is divided into three parts for the efficient machining. The formed tools are designed and shared for the respective split region. By cutting the screw rotor using the formed tools, this method is more efficient than the end mill in machining rotor. Experimental results show that 4-axis machining using formed tools needs less time and has the accuracy.
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We will improve tools performance without the change of a tools' physical shape, if we process mirror like finishing on the surface of cutting tools. Because cutting tools' shapes are very complex, the general method of polishing can't be polished. So we will apply new method of polishing which is magnetic fluid grinding technique. Magnetic fluid grinding technique can polish complex shape's workpiece by pressing the surface of workpiece with magnetic and abrasive grains in magnetic field. Therefore we developed the polishing equipment to improve the performance of cutting tools and experimented on various polishing conditions to determine the polishing conditions of cutting tools.
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In this study, combined micro press and surface finishing process are proposed to fabricate the micro nozzle array on a stainless steel sheet metal. In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. For this reason, subsequent magnetic field-assisted finishing technique is applied to remove the burr which exists around the nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals were investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.
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Current mechanical devices are trending toward being a small size, high speedy, automation. For performing these functions, machinery elements organizing a machine should be designed exactly. Cams have high confidence and economics in ablility to transmit a motion. Accordingly, A cam mechanism is very important for processing the machine automatically. This paper introduce an inverse cam mechanism. A square shaped cam which cannot be commonly analyzed is designed and manufactured by using the NURBS interpolation algorithm. The objective of this paper is to develop a computer-aided design program. In this paper, a displacement curve of oscillating motion inverse cam mechanism with square shaped follower is analyzed. The data is redistibuted by the NURBS algorithm. A cam shape is designed by the instant velocity center method, and simulated to verify the validity of the operation state.
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The mechanical properties of bellows, such as the extensibility and the strength can be changed depending on the shape. For the shipbuilding material, it is favorable that the fatigue life is long due to the elastic property and the reduction of thermal stress in piping system. Nowadays, the domestic production and design of bellows are based on the E.J.M.A Code. Therefore, the design standard is in need because of much errors and lack of detailed analysis. In this study, it is attempted to find out the optimal shape of U-type bellows using the finite element method. The effective factors, mountain height, length, thickness, and number of mountains and the length of joint are considered and the proper values are chosen for the simulation. The results shows that if the number of mountains are reduced, the volume decreases while the stress increases. However, the number of mountains are increased, the volume increases above the standard volume and the stress obviously increases. In addition, the effect of the thickness of bellows on the stress is very large. Both of the volume and stress are decreasing at a certain lower value region.
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ATM is element that reliability, stability is important in relation with customer by financial agency used device. To embody high reliability and stability, reliability estimation technology development is important. When new product is developed, performance and reliability evaluation of product are essential element. In this paper, is treating contents on reliability estimation of stepping motor, BLDC motor and solenoid that is main driving source of note handling units.
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Recently drum washing machines are required to improve not only functions, but also endurance security. The spider is one of the major parts in a drum washing machine as a power transmission device. It is needed estimating for fatigue life because it rotates at high velocity when the drum washing machine works. In this study, we tried to estimate fatigue life of the Spider with CAE and verified the accuracy by comparing the CAE results with the experimental results. The estimation method of fatigue life for the spider with CAE will be applied to raise the efficiency of time and money in the design process of a new drum washing machine.
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Using hyper-elastic material has been increased gradually and its range was extended all over the industrial. In addition, the performance prediction of this material was required not only experimental methods like metal material but also numerical methods. In this study, we presented the process how to use numerical method for hyper-elastic material and then, it was applied for seat-ring of butterfly valve by using this process. The finite element analysis was executed to evaluate the mechanical characteristics of hyper-elastic material and search the optimum model considered conditions and features. According to that model the coefficient was obtained by using Contact analysis.
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The main objectives of this research work are to develop conductive glass fiber woven roving and carbon fiber unidirectional fabric composite materials and to determine their electromagnetic shielding effectiveness(EMSE). Epoxy is the matrix phase and glass, carbon fiber are the reinforcement phase of the composite material. Carbon black are incorporated as conductive fillers to provide the electromagnetic shielding properties of the composite material. The amount of carbon black in the composite material is varied by changing the carbon black composition, woven roving and unidirectional (fabric) structure. The EMSE of various fabric composites is measured in the frequency range from 300MHz to 800MHz. The variations of EMSE of woven roving and unidirectional composites with fabric structure, metal powder composite are described. Suitability of conductive fabric composites for electromagnetic shielding applications is also discussed.
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A product is designed through the collaboration among engineers in several fields such as design, analysis, and manufacturing. These series of functions are performed repeatedly during the design process. An easy access and exchange of the model data is one of the important elements that help to shorten production development time. Especially, the importance of data exchange between CAD and CAE applications is increasing in the field of verification and estimation of the products. However, information and knowledge of model which is generated by a CAD software cannot be transferred by a function of CAE software, as an exchange of product data between CAD and CAE applications. It causes a delay in design analysis and eventually discourages a designer's effort in improving his design. Therefore, we need to integrate a commercial CAD and CAE applications effectively and to use the same interface on a product model obtained in a distributed environment. This paper shows how to implement a model exchange between CAD and CAE by a web-service and how to provide a communication environment among engineers.
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It could make the LIghtweight Piezoelectric Composite Actuator (LIPCA) damageable by the cyclic large deformation. If the progressive microvoid coalescence of LIPCA interlaminar took place, the decrease of the stiffness and the weakness of stress transmission and fiber bridging effect would make the fatigue characteristics worse suddenly. Therefore, it is required to study the variation of fatigue behavior and interlaminar condition in LIPCA under resonant frequencies. These studies such as the changeable fatigue phase and interlaminar behavior of LIPCA affected by the resonant frequencies should be carried out due to the strong anisotropy of CFRP layer. Hence, these studies are as follows. 1) The residual stresses distribution of interlaminar in LIPCA using the Classical Lamination Theory (CLT). 2) Comparative analysis of interlaminar behavior for the intact LIPCA versus LIPCA containing an artificial delamination during resonant frequency.
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A rheology casting technology has some advantages compared with conventional forming processes such as die casting, squeeze casting and hot/cold forming. The liquid segregation is important on mechanical properties of materials using rheology casting. In this study, so, molecular dynamics simulations were performed for the control of liquid segregation. Because the dynamics of fluid flow about nano-scaled materials is completely different from continuum, molecular dynamics simulations were used. The behavior of particles was far from the truth according to boundary conditions in simple flow. But various movement of particles appear at two or more molecular simulations.
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This study was aimed to verify the acceptable contact force between power collector and 3rd rail type conductor rail for the Korean standardized rubber-tired AGT light rail vehicle. The power collector was designed and manufactured to satisfy the Korean standardized Specifications of the rubber-tired AGT light rail vehicle. Based on the dynamic behavior, contact force variation and interruption in the worst installation tolerance of the conductor rail, its initial contact force was set up. At the test track for the Korean standardized rubber-tired AGT light rail vehicle, interruptions, stresses, vibrations, and contact force variations were measured. As the results, initial contact force was verified to ensure power collection stability.
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We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.
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This paper is to investigate a defect for thermal barrier coating layers by acoustic emission method in 4-point bending test. The two-layer thermal barrier coating is composed of
$150\mu{m}\;CoNiCrAlY\;bond\;coating\;by\;vacuum\;plasma\;spray(VPS)\;process\;and\;250\mu{m}\;ZrO_2-8wt%Y_2O_3$ ceramic coating layer by air plasma spray(APS) process on Inconel-718. The specimen prepared by cyclic thermal test(500, 1000, 2000cycle) at$1050^{\circ}C$ The AE monitoring system is composed of PICO type sensor, a wide band pre-amplifier(40dB), PC and AE DSP(16/32 PAC) board. The AE event, amplitude, Cumulative energy and count of coating specimens is evaluated according to cyclic thermal test. -
A CAM program for forming design Automated of CAM for Spring using car was developed in this study. This program was written in AUTO-LISP on the AUTO-CAD system with a personal. An approach to the system is based on the kinemateic of the object function. We make a determination of an cam programming. A cam spline is continuous in displacement, velocity and acceleration. The best cam curve is obtained by changing the kinemateic of the object function. The result has improved all characteristics such as velocity, acceleration and displacement compared with that of the modified cycloid curve.
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The Ni-base superalloy GTD-111DS was designed in the 1970s and is widely used as the material of the first stage blade under a severe combination of temperature and pressure in gas turbines. But because GTD-111DS is distributed in the shape of blade and blade has a unique figure and many cooling channels, it is hard to manufacture the test specimen. In this reason, there are little data on the microstructure and mechanical properties of the alloy. Therefore through the microstructure analysis, present paper observed that the shape of
$\gamma{'}$ did not change even if aging time was increased but the amount and volume of the deposition of secondary$\gamma{'}\;rose\;and\;secondary\;\gamma{'}\;grew\;among\;primary\;\gamma{'}$ . Also, by tensile test for different temperature, there was difference between yield strength and tensile strength in room temperature on heat treatment and extracting region but the more increasing temperature, the more decreasing difference between yield strength and tensile strength. -
The tiebar is used by joint for keeping from deformation by conserving tensile load between two structure. The tiebar, bolt joining type, is combined by tiebar and clevis like bolt and nut. By coupled, it maintains tensile load. While it goes through repeated load, it occurs to loose because joining force between clevis and nuts is reduced. So, continuos maintenance is needed such as making tighter periodically, repairing the broken part and so on. For that reason, this paper calculates necessary torque unfastening joint for conventional tiebar and presenting tiebar theoretically and then consider the reason that conventional bolt-typed tiebar unties. Also, through vibration untied test for two types of tiebar we confirm that presenting tiebar have a improvement of unfastening when we compare with the conventional one.
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Microcellular foam processing of polymers requires a nucleated cell density greater than
$10^9\;cells/cm^3$ so that the fully grown cells are smaller than 10 mm. A microcellular foam can be developed by first saturating a polymer sample with a volatile blowing agent, followed by rapidly decreasing its solubility in the polymer. In general, the cellular structure of crystalline polymer foams is difficult to control, compared to that of amorphous polymer foams. Since the gas does not dissolved in the crystallites, the polymer/gas solution formed during the microcellular processing is nonuniform. Moreover, the bubble nucleation is nonhomogeneous because of the heterogeneous nature of the crystalline polymer. In this paper, the effects of the crystallinity and morphology of crystalline polymers on the microcellular foam processing and on reflectivity of products are investigated. First, polymer specimens with various morphology and amount of solved blowing agent were prepared by varying the saturation pressure, saturation time and foaming condition. Then, cell morphologies according to several conditions were studied. The specimens with differing gas amount of solved and morphologies were foamed and their cellular structures were compared. The experimental results of reflectivity are compared to raw specimen and another specimen of different experimental conditions. After the experiments, recognize whether how reflectivity changes according to solved gas amount. And the effect of cell density and cell size on reflectivity is studied -
The paper has analyzed the influence of tire design variable on the tire Force and Moment (F&M) characteristics, especially by the belt angle, the Plysteer Residual Aligning Torque (PRAT) which is considered as one of the causing factors for the vehicle pull. To validate the tire FE model, the tire stiffness and the PRAT which can be derived from the simulation data have been compared with the experimental data of test machine. In addition to PRAT characteristic, the tire stiffness and cornering characteristics due to the belt angle have been investigated. The effects of drum's curvature on the PRAT have been also investigated using the tire FE model and the usefulness of the current drum type F&M test machine can be confirmed.
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In recent automotive industry, vehicle weight can be reduced by one-step forming of tailored blanks welded with two or more sheets of metal blanks. Tailored blank(TB) welding is a production method for blanks involving welding together materials of different quality, thickness, and coating, and has proved popular in fabrication automotive parts. This paper deals with the forming characteristics of mash seam welded tailored blanks. Using these forming characteristics, the bumper beam was developed using the mash seam welded tailored blank with the different thickness. We performed the forming simulation with respect to strain distribution on blank during the stamping of the bumper rail part. Based on these results, we made some stamping tryouts with selected types of blank designs to investigate the formability of tailored blank with different thickness. During the tryouts, we knew that it was important the BHF(Blank Holding Force). We obtained to reducing 10.5% weight and cost with adapting the bumper beam of automotive component using the tailored blank of mash seam welding.
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In these days, the piezoresistive material has been applied to various sensors in order to measure the change of physical quantities. But the relationship between the sensitivity of a sensor and the position and size of piezoresistor has rarely been studied. Therefore, this paper was focused on the distribution of the resistance change ratio on the diaphragm and bridge surface where piezoresistor would be formed, and proposed the proper size and position of piezoresistor with which the sensitivity of sensor was increased. As the width of mass and boss was increased, the distance between piezoresistors was closed and the maximum value of resistance change ratio was decreased by the increase of the structure stiffness. And according to the increment of seismic mass size, the value of resistance change ratio is decreased by increase of the structure stiffness. Y directional piezoresistor is formed in the position of
$100\mu{m}\;apart\;from\;cantilever\;edge\;and\;length\;of\;that\;is\;800\mu{m}$ . -
This paper describes the design, analysis and manufacture procedure of the composite blade for hingeless rotor system of unmanned helicopters. Helicopter rotor system is the key structural unit that produces thrust and control forces for intended flight conditions. In this work, a hingeless rotor system is adopted, and base on the design requirements for rotor system, composite blade section design and calculation of material properties were performed. In order to avoid the unstable state such as resonance, vibration characteristics of rotor system were analyzed. Finally, this paper describes the forming and manufacture of composite blade.
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The hardening model based on the dislocation mechanics is employed to study the experimentally observed high tensile elongations of NiAl along the [110] orientation at intermediate temperatures. In the hardening model proposed, a mobility of dislocation is assumed to be restricted to glide through the slip plane by forest dislocation and thermally activated cross-slip event. Overall deformation behavior of NiAl was greatly influenced by temperature-dependent dislocation mobility that both experimental and simulated yield stresses decreased as temperature increased. The results of simulation showed anomalous hardening behaviors analogous to those of experiment at certain circumstances. This behavior occurred due to the hardening contributions generated by cross-slip events that disable the dislocation motion in the primary slip systems. By comparing simulation results with experiments, it is confirmed that the proposed hardening model can represent anomalous tensile elongations due to the hardening by forest dislocations and cross-slip events.
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The object of this study was to design of micro stage, which is one of the equipments embodied in ultra precision positioning mechanism. Design factors for micro stage were decided a roundness of hinge, a thickness of hinge, a thickness of stage, a length of arms and a clearance of division. To obtain the
$1^{st}$ natural frequency and equivalent stresses, FEM simulation was performed using the table of orthogonal arrays and Taguchi method was used to determine the optimal design parameters. As results of this study, the size of 1st natural frequency and equivalent stresses on micro stage was influenced significantly by a thickness of hinge and a length of arm. -
The nano/microstructure, the aging response (in T5 heat treatment), and the mechanical/tribological properties of the eutectic regions in squeeze-cast A356 alloy were investigated using nano/micro-indentation and mechanical scratching, combined wit optical microscopy and atomic force microscope(AFM). Most eutectic Si crystals in the A356 alloy showed a modified morphology as fine-fibers. The loading curve for the eutectic region was more irregular than that of the primary Al region due to the presence of various particles of varying strength. In addition, the eutectic region showed lower pile-up and higher elastic recovery than the primary Al region. The aging responses of the eutectic regions in the squeeze-cast A356 alloys aged at
$150^{\circ}C$ for different times(0, 2, 4, 8, 10, 16, 24, 36 and 72 h) were investigated. As the aging time increased, acicular Si particles in the eutectic regions gradually came to a fine structure. Both Vickers hardness ($H_V$ ) and indentation ($H_{IT}$ ) test results showed almost the same trend of aging curves, and the peak was obtained at the same aging time of 10 h. A remarkable size-dependence of the tests was found. The friction coefficient for the eutectic region was lower than that for the primary Al region. -
This paper describes the result of structure analysis of secondary bogie frame. The purpose of the analysis is to evaluate an safety which secondary bogie frame shall be considered fully sufficient rigidity so as to satisfy proper system function under maximum load. Secondary bogie system consist of bogie frame, suspensions, wheel-sets, and brake system. Among these component, the bogie frame is most significant component subjected to the vehicle and passenger loads. The evaluation method is used the JIS E 4207 specification throughout the FEM analysis. The analysis results have been very safety and stable for design load conditions.
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The creep rupture data for type 316LN stainless steels were collected through literature survey or experimental data produced in KAERI. Using these data, polynomial equations for predicting creep life were obtained by Larson-Miller (L-M), Orr-Sherby-Dorn (O-S-D) and Manson-Haferd (M-H) etc. time-temperature parametric (TTP) methods. Standard error of estimate (SEE) values for the each parameter was obtained with different temperatures through the statistical process of the creep data. The results of L-M, O-S-D and M-H methods showed good creep-life prediction, but M-H method showed better agreement than L-M and O-S-D methods. Especially, it was found that SEE values of M-H method at
$700^{\circ}C$ were lower than that of L-M and O-S-D methods. -
Special considerations on the design of liquid storage tanks should be taken into account for seismic and wind loads. But Korean industrial standard KS B 6225 does not specify detailed guidelines for a design. It is therefore necessary to improve design guidelines for a seismic and wind-proof design in KS B 6225. The purpose of this study is provide a basis for the development of improved seismic and wind-proof design procedures, especially about seismic and wind loads.
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Design and manufacturing of plastic injection mold with cavity pressure/temperature sensors were performed in the present study for tensile test specimen. Standards of mold-base and tensile test specimen were used to design an injection molding system. Cavity pressure and temperature sensors were placed on the side of fixed platen of injection mold machine to prevent them from external impact damage. Injection molding experiments with variations of injection speed and melt temperature were performed and polycarbonate tensile specimens were prepared for the tensile test. It was shown that injection molding processing parameters can have effect on the mechanical properties of the plastic injection molded part.
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Micro Cellular Plastics create a sensation at polymer industrial for lowering product cost & overcoming a lowering of mechanical intensity. Reduction of MCPs cell size increases the intensity of MCPs. This research based on the experiment about cell size reduction method. At this study, Quenching & Pressure foaming process are introduced to one of methods. Conclusion of study is that Quenching process is the simplest process for nano cell formation.
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This paper describes a dedicated three-dimensional CAD system for design of drawing dies for automotive body panels. Since solid die models are useful not only for simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns, 3-D CAD systems have been introduced in the tooling shop of automotive manufacturers. However, the work to build solid models requires a lot of time and effort if the designer uses only the general modeling capabilities of commercial 3-D CAD systems. To solve this problem, we customized a 3-D CAD system for the drawing die design. The system provides not only 3-D design capabilities, but also standard part libraries to enhance design productivity. By introducing this system, the drawing dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing
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This work is towards the development of a low-cost, small-sized inertial navigation system(INS) which consists of 3 accelerometers, 3 semiconductor gyros and a magnetic compass sensor. This paper explains in detail the structure of the developed system and proposes a 3 dimensional attitude estimation algorithm with Indirect Kalman Filter. The experiments are performed with the developed system attached to a 6 DOF robot for showing the effectiveness of the algorithm.
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Until now, strain gage technique and accelerometer for the diagnosis safety of constructions are used widely. However, the limits of these methods are revealed. But Electronic Speckle Pattern Interferometry(ESPI) that uses Pulse Laser is noncontact, whole-field, real-time measuring method also dull to disturbance and can achieve test result in a very short time. It has various strong point in spot application, swift establishment, and dynamic conduct analysis for the entire field of Laser illuminate. This author analyzed vibration characteristic of using the Pulse ESPI System, the diagnosis safety of bridges, to simplify the analysis of the dynamic conduct of a large construction.
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To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In this system, measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is
$100um\times{100um}$ . And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. Using this AFM system, 3um pitch specimen was measured. As a result, the uncertainty of total system has been evaluated. -
Several test methods, including micro strain/deformation measurement techniques, have been studied to more reliably measure the micro properties in micro/nano materials. Therefore, in this study, the continuous measurement of in-plane tensile strain in micro-sized specimens of thin film materials was introduced using the micro-ESPI technique. TiN and Au thin films 1 and
$0.47\;\mu{m}$ thick, respectively, were deposited on the silicon wafer and fabricated into the micro-sized tensile specimens using the electromachining process. The micro-tensile loading system and micro-ESPI system were developed to measure the tensile strain during micro-tensile test. The micro-tensile stress-strain for these materials was determined using the algorithm for continuous strain measurement. Furthermore, algorithm for enhancing the sensitivity to measurement of in-plane tensile strain was suggested. According to the algorithm for enhancement of sensitivity, micro-tensile strain data between interfringe were calculated. It is shown that the algorithm for enhancement of the sensitivity suggested in this study makes the sensitivity to the in-plane tensile strain increase. -
The purpose of this study is the real-time shape measurement of three-dimensional object by using color coded information. The paper relates to non-contact optical measurements of surface profiles or displacements, because of optical measurement systems are advantageous over using mechanical sensing, their relatively high speed and non-destructive capabilities. Therefore is particularly useful for three dimensional sensing which requires high horizontal and vertical resolution of measurements over a wide range thereof. Each a red, blue, green by using a inherence colors of hue value are good point.
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In this paper, the control strategy of the tension and speed based a prototype bio-wrap winding machine is developed. The decentralized control strategy using PID control algorithm applied for each subsystem is proposed to control the each system's desired outputs, because the tension of each subsystem effects that of next roll system. The computer simulations and the experiment results are presented to show that the proposed control scheme is feasible for a prototype bio-wrap winding machine.
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This paper presents the method of reducing torque ripple of Blushless Direct Current(BLDC) motor. In the BLDC motor, the torque is decided by the back-EMF and current waveform. If the back-EMF is constant, the torque ripple depends on the current ripple during commutation period. The current in commutation period is acquired by circuit analysis and then the torque ripple simply can be reduced by varying input voltage to flow the current continuously. And suggested method is confirmed by dynamic with parameters of 500W BLDC motor.
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The paper deals with the structural vibration and noise characteristics of pipe structures. In general, A structure bone noise has a great effect on the drain noise of toilets, and depends on the natural frequency of the related structures. In order to measure and to find the relationships between structural vibration and noise of the pipe structures, some experiments have been performed. Through the experiments, impact acceleration signal in time domain and magnitude of transfer function in the frequency domain have been investigated for three kinds of pipes. Transmission loss of pipes depending on the frequency ranges was also found by using small speakers as a sound source.
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This paper proposes an analytical redundancy technique for fault diagnostics of the sensor in steer-by-wire system. We use incorporating vehicle dynamics modeling into the design of a diagnostic system for steer-by-wire system. The use of a model of vehicle dynamics improves the speed and accuracy of the diagnoses. The proposed fault diagnostics algorithm is based on parity-space methods to generate residuals. To reduce the effects of modeling uncertainty and dynamic transients, the residuals are subject to filtering. We construct diagnostic system consisting residual threshold for detection and isolator with using the directional residual vector.
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This Paper is to find out a solution for the full-coverage algorithm requiring the real-time processing such as mobile home service robots and vacuum cleaner robots. Previous methods are used by adopting based grid approach method. They used lots of sensors, a high speed CPU, expensive ranger sensors and huge memory. Besides, most full-coverage algorithms should have a map before obstacle avoidance. However, if a robot able to recognize the tangent vector of obstacles, it is able to bring the same result with less sensors and simplified hardware. Therefore, this study suggests a topological based approach and a local obstacle voidance method using a few of PSD sensors and ultra sonic sensors. The simulation results are presented to prove its applicability.
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Recently, the performance development of the exhaust system of a car is very important. The most important part of parts that constructing the exhaust system of a car is a muffler. The muffler reducing the exhaust noise from the engine influence on the engine performance directly. The inner parts of the muffler construct with the baffle and perforated pipes and so on. In the recent study, the study to design the semi-active muffler sensing the exhaust gas pressure controlling the back pressure variably with a EVV progress activity. So that the inner parts of the muffler show the complicated turbulent flow phenomena because of pulsatile flow from the engine and the structural properties and so on. The qualitative and quantitative analysis about the turbulent flow phenomena of the inner parts of the muffler is required gradually. In this study, to analysis the flow field of the inner parts of the muffler, analysis results with the PIV measurement to be able to analysis the variable change of the time and the space. Therefore, try to show the design variables to need to design the inner parts of a muffler of a car.
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Since it is a very issue that figures out a current position of mobile robots, various methods have been proposed until nowadays. This paper proposes the sensor model of RFID(Radio Frequency Identification) and position estimation algorithm for mobile robots. We designed the sensor model of RFID in experimenting repeatedly. The sensor model of RFID in this case is that of stochastics according to sensing rate. Based on this stochastic sensor model, we designed the algorithm which estimates distance and direction of RFID tag. Therefore we made sure that RFID tag is used as landmark.
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As the development of microprocessor technology, electric power steering(EPS) system which uses an electric motor came to use a few years ago. It can solve the problems associated with hydraulic power steering. The motor only operates when steering assistance is needed, so it can save fuel and can reduce weight and cost by eliminating hydraulic pump and piping. As one of performance criteria of EPS systems, the transmissibility from road wheel load to steering wheel torque is considered in this paper. The transmissibility can be studied by fixing the steering wheel and calculating the torque needed to hold the steering wheel from road wheel load. A proportion-plus-derivative control is needed for EPS systems to generate desired static torque boost and avoid transmissibility of fluctuation. A pure proportion control can' satisfy both requirements.
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Compared to other nano-patterning techniques, Nano imprint Lithography (NIL) has some advantages of high throughput and low process cost. To imprint low temperature and pressure, UV Nano imprint Lithography, which using the monomer based UV curable resin is suggested. Because fabrication of high fidelity pattern on topographical substrate is difficult, bi-layer Nano imprint lithography, which are consist of easily removable under-layer and imprinted pattern, is being used. If residual layer is not remained after imprinting, and under-layer is removed by oxygen RIE etching, we might be able to fabricate the bi-layer pattern for easy lift-off process.
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In this paper, we describe a simple, precise and low cost method of fabricating PDMS stamp for UV embossing. It is important to improve the replication quality of stamp because the accuracy of fabricated structure is related to that of the stamp in UV embossing. The PDMS stamp has been fabricated by the replica molding technology with ultrasonic vibration to eliminate micro-air bubbles during the fabrication process of PDMS stamp. Also, this fabrication to use ultrasonic vibration promotes PDMS solution to fill into micro channel and edge parts. We report the fabrication of an optical core using UV embossing with fabricated PDMS stamp. This fabricated core is
$7\;\mu{m}\;at\;depth,\;6\;\mu{m}\;at\;width.\;This\;measured\;value\;has\;the\;difference\;below\;1\;\mu{m}$ compared to the original stamp. The surface roughness of core is about 14 nm root mean square. This is satisfactory value to use low-loss optical waveguide. Our successful demonstration of precise replica technology presents an alternative approach for the stamp of UV embossing. -
This paper accomplished the basic research using the hydrostatic extrusion to make the nano-grained bulk material. It was carried out a hot hydrostatic extrusion using the hipped bulk Al-7.5%Mg that was taken from University of California, Davis. in order to investigate the effect of the hot isostatic extrusion. The tensile tests for the hipped bulk Al-7.5%Mg and the extruded one was executed and the results was compared.
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Lee Dong-Jin;LeBrun Thomas W.;Balijepalli Arvind;Gorman JasonJ.;Gagnon Cedric;Hong Dae-Hie;Chang Esthe rH. 1501
This paper presents the design of a multiple beam optical tweezers instrument used for manipulating micro/nano-sized components. The basic equations used in designing the optical tweezers are derived and the stable and time-sharing multiple beam optical tweezers are constructed with scanning mirrors. The laser beam passes through a series of optical components such as lenses, mirrors, and scanning mirrors, and overfills the entrance aperture of microscope objective, which gives a stable trap. By rotating the laser beam with the scanning mirror, the focal positions are translated in the specimen plane and multiple micro/nano-sized objects can be moved. The constructed optical tweezers is used to manipulate cells and liposomes simultaneously and to trap multiple nano-wires. The experiments prove that the developed optical tweezers can be a very versatile manipulation tool for studying gene therapy and nano device fabrication. -
This study was carried out as a part of the research on the development of a maskless and electroless process for fabricating metal micro/nanostructures by using a nanoindenter and an electroless deposition technique.
$2-\mu{m}-deep$ indentation tests on Ni and Cu samples were performed. The elastic recovery of the Ni and Cu was 9.30% and 9.53% of the maximum penetration depth, respectively. The hardness and the elastic modulus were 1.56 GPa and 120 GPa for Ni and 1.49 GPa and 100 GPa for Cu. The effect of single-point diamond machining conditions such as the Berkovich tip orientation (0, 45, and$90^{\circ}$ ) and the normal load (0.1, 0.3, 0.5, 1, 3, and 5 mN), on both the deformation behavior and the morphology of cutting traces (such as width and depth) was investigated by constant-load scratch tests. The tip orientation had a significant influence on the coefficient of friction, which varied from 0.52-0.66 for Ni and from 0.46-0.61 for Cu. The crisscross-pattern sample showed that the tip orientation strongly affects the surface quality of the machined area during scratching. A selective deposition of Cu at the pit-like defect on a p-type Si(111) surface was also investigated. Preferential deposition of the Cu occurred at the surface defect sites of silicon wafers, indicating that those defect sites act as active sites for the deposition reaction. The shape of the Cu-deposited area was almost the same as that of the residual stress field. -
The polymer-light emtting diodes(PLEDs) were comprised a design of OLED array, process develop by using ITO thin glass, and fabrication of PDMS stamp by using nanocontact printing. In the study, we describe a different approach for building OLEDs, which is based on physical lamination of thin metal electrodes supported by a PDMS stamp layer against an electroluminescent organic. We develop that devices fabricated in this manner have better performance than those constructed with standard processing techniques. The lamination approach avoids forms of disruption that can be introduced at the electrode organic interface by metal evaporation and has a reduced sensitivity to pinhole or partial pinhole defects. Also, it is easy to build patterned PLED with feature sizes into the nanometer regime. This method provides a new route to PLED for applications ranging from high performance displays to storage and lithography systems, and PLED can used for organic electronics and flexible display.
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In recent years, as the demands of VBNS(Very high speed Backbone Network Service) and VDSL(Very high-data rate Digital Subscriber Line) increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, WDM elements increase. The alignment and the attachment technology are very important to fabricate the optical elements for communication. In this paper, the mechanism of rotational stage are studied. with the three different method and the results of them are applied to the design of the system. The performance test of resolution and travel is performed.
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The application of focused ion beam (FIB) technology in micro/nano machining has become increasingly popular. Its usage in micro/nano machining has advantages over contemporary photolithography or other micro/nano machining technologies such as small feature resolution, the ability to process without masks and being accommodating for a variety of materials and geometries This paper focus to apply the sputtering technology accumulated by experiments to 3d structure fabrication with high resolution. Therefore some verifications and discussions of the characteristics of FIB sputtering results according to focal length were described in this paper. And we suggested the definition of rectangular pattern profile and made the verifications of sputtering results based on definition of it.
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In this study, the fabrication of large area silicon mirror is accomplished by anisotropic etching using MEMS for implementation of integrated optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped
$9.74^{\circ}$ off-axis-cut silicon wafer using wet etching. In addition rough surface of the mirror is achieved in case of long etching time. Hence a novel method called magnetorheolocal finishing is introduced to enhancing the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of$mm^2$ and it is applicable to optical pickup using infrared wavelength. -
In the semiconductor and optical industry the non-contact transportation is required for reducing the damages. The ultrasonic levitation is the solution of the problem. In this paper, the ultrasonic levitation system and 3 disk-type stator for levitation various object are proposed. The vibration modes of disks are analyzed with FEM and designed with the analysis results. The 3D vibration profiles of the disks are measured by Laser scanning vibrometer for verifying the vibration characteristics of the system. The amplitudes of the disks and the levitation heights of object are measured for evaluating the performance.
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Nano pattern is being utilized to produce micro optical components, sensors, and information storage devices. In this study, a study on nano pattern fabrication using raster-scan type Focused Ion Beam (FIB) milling is introduced. Because the intensity of ion beam has Gaussian distribution, the overlapping of the Gaussian beam results in a 3D pattern, and the shape of the pattern can be adjusted by variation of FIB milling parameters, such as overlap, ion dose, and dwell time. The Gaussian shape of single beam intensity has been investigated by experiment, and 3D nano patterns with pitch of 200nm generated by FIB is demonstrated.
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We present a mass productive and reproducible assembly technique of a single bundle of single-walled carbon nanotubes (sb-SWNTs) using dielectrophoresis (DEP). Gold electrodes with 10 gaps made via microlithography were used to align the carbon nanotubes (CNTs). The magnitude and type of applied electric field were investigated to verify their effects on CNT assembly. The optimum assembling conditions in which sb-SWNTs could be positioned at a desired site were experimentally identified, and the characteristics of the assembled sb-SWNTs were evaluated from AFM, Raman spectroscopy, and I-V curve. This assembly method has potential for applications such as gas sensors or electronic devices.
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Self-assembled monolayers (SAMs) formed by the adsorption of alkanethiols,
$HS(CH_2)_nX$ , where X is an organic functional group, onto gold surfaces have attracted widespread interest as templates for the fabrication of molecular and biomolecular microstructures. Previously photopatterning has been thought of as being restricted to the micron scale, because of the wellknown diffraction limit. So, we have explored a novel approach to nanofabrication by utilizing a femtosecond laser coupled to a near-field scanning optical microscope (NSOM). -
This paper presents a method to measure a large surface shape using atomic force microscopy, which has been used mostly for measuring over very tiny surfaces. Experiments are performed to measure a step height and a slope of a test sample. The proposed method is rigorously compared with the coordinate measuring machine. The repetition accuracy and the effects of the set point are also studied. The experimental results show that the proposed method is reliable and should be effective to measure both the nano-accuracy surface profile as well as the micro-accuracy global shape of a macro/micro parts using atomic force microscope.
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ISB panel, inner structured of metal in two skin and bonded, has inner structures which have low relative density, stiffness and strength with low weight of make improvement for that purpose. A kind of Inner structures have various structure types. In this paper, we have studied the Forming Limit Diagram(FLD), thickness variation and stress strain to dimple structure of sheet by analysis of Dynaform and LS-Dyna.
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The Titanium has many superior characteristics Which are specific strength, heat resistance, corrosion resistance, organism compatibility, non-magnetic and etc. and their quantity are abundant. this study performed turning operation of Ti-6Al-4V alloy using the TiAlN Coate Tool which treated PVD (Physical Vapor Deposition). Experimental works are also executed to measure cutting force, chip figuration and surface roughness for different cutting conditions. As a result of study. Tool wear was serious at over 100m/min of cutting speed and cutting condition was excellent at 1.0mm of cutting depth.
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In this study, we measured cylindricity and Runout of the air bearing spindle, and tested PCB(printed circuit boards) drilling with 0.4mm micro drill at 90,000rpm and 110,000rpm in order to obtain drilling hole error. Results are as follows; The air bearing spindle's Runout was not so high within
$10\mu{m}$ from 20,000rpm to 80,000rpm but it grew after 80,000rpm. Drilling hole size error was 9% at 80,000rpm and 12% at 110,000rpm because of spindle's Run out. Drilled hole shape falsified more 110,000rpm than 90,000rpm. -
Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional arc welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameters such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar plates, etc. The following conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/ aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.
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The aspherical lenses are used as optical lens of HMD optical system. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the diamond tool nose radius, the cutting speed, the feed rate, the depth of cut, and cutting fluid type are found. The demanded surface roughness 10 nm Ra, aspherical form error
$1.0\;\mu{m}$ P-V for aspherical lens of optical data storage device are satisfied. -
Generally, the kerosene or the deionized water has been used for dielectric fluid in the electrical discharge machining. The spark occurs when the voltage is over the breakdown voltage and induces high temperature. In this study, the Oxygen gas is used as the dielectric. The voltage behavior in the dry Micro Electrical discharge machining is compared with that of the conventional Micro Electrical discharge machining. The dry Micro EDM has some advantages. The electrode wear isvery smaller than that of the conventional Micro EDM. The contamination in the dry Micro EDM can be drastically reduced comparing to that of the conventional Micro EDM. The Oxygen gas can be replaced as the dielectric successfully.
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As GA(Galvannealed sheet steel, GA) has good corrosion resistance, weldability and paintability as well as excellent stamping formability it's demand is rapidly increasing for automotive panel. But the layer of the Galvannealed sheet steel is easy to have a coating layer such as powdering and flaking in the press process because it is composed of Fe-Zn alloy. Therefore, the process condition is properly required to form the surface treated sheet steel. The frictional characteristics with dies are changed according to the annealing temperature,
$505^{\circ}C,\;515^{\circ}C\;and\;540^{\circ}C$ during the process. To obtain the frictional characteristics of GA sheet steel in this study, on flat friction test is conducted. The friction coefficient is compared with the variation of pressure and velocity, viscosity of lubricant at the various galvannealed temperatures. -
Polishing is cutting process that polished workpiece by relative motion of abrasive grain between polishing tool and workpiece. According to relative motion forms(polishing patterns) of abrasive grain, the surface quality is different. Then, polishing patterns are important essential in polishing process. In work field, polishing patterns are determined by an expert of experience. Therefore, to work effective polishing, it is necessary that evaluate polishing characteristics for polishing patterns. And, polishing machine is made with cartesian coordinate robots, we estimate polishing characteristics by measurement of surface roughness.
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Grinding process is different from other machining processes such as turning, milling and drilling because the cutting edges in a grinding wheel doesn't have uniformity and acts differently on the workpiece at each grinding. This study focus on predicting the geometric error produced during surface grinding and selecting an optimal grinding condition to reduce the geometric error. To achieve the aim, the Taguchi design of experiments was applied and the S/N ratios of each grinding was used for evaluating the results. The predicted quantities by the S/N ratios were compared with the experimental results.
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A rigid-plastic finite element analysis for the die forging process of a socket ball joint, which is used in the transportation system, was carried out. And also with the results, the elastic stress analysis for the forging die was performed in order to get basic data for the die life prediction. The die fatigue life prediction was simulated using Goodman's and Gerber's equation. The prediction technique for the fatigue life of a forged product, the socket ball joint, using DEFORM-3D is presented and the results are commented upon. Archard's wear model was used for the wear simulation and then the wear simulation and then the wear quantity was quantity was evaluated using volume. In order to prove the wear simulation results to be reliable, wear quantity of the real forging die set in used a forging factory was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.
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In this paper, we designed the aspheric lens by mathematical methods which are solved by refractive index. Based on these mathematical method, we manufactured the aspheric lens. Because of the usefulness of manufacturing, we used the acryl as the material. And we used a high speed machine to manufacture the aspheric lens. Also it sits in judgment the aberration of spherical distribution by using the grid fringe. Asource of laser produced by laser sheet generator passed the optical system of the aspheric lens. Though a character is to verify that the accuracy of the aspheric lens by experiment of the straight character.
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Recently, the trends of TFT-LCD are large scale and thin thickness, so, the demands of Light Guide Panel(LGP) which is able to substitute for prism sheets are appeared. Functions of LGP obtaining polarization of light of the prism sheet as well as the incidence and reflection of light are demanded. This prismless type LGP to complete functions of the existing LGP and polarization at once must be supported by micro machining technology of LGP surface. In this research, we have used the STAMPER method for the mass product and In-Line process, and the optimized conditions are established by analyzing the cutting force and conditions according to the material and processing properties when the prismless type LGP mold is fabricated. Parameters of the cutting condition were the workpiece and cutting depth.
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The demand increasing of optical applications like as display devices derives interest for fabrication process. The product s development is apt to fabricate numerous thin and wide surfaces with micro pattern. Naturally that needs injection molding fabrication for the mass production. In existing manufacturing, the product quality is controlled by input fabrication condition from the outside. That can be called as a try and error method and not fundamentally solve the troubles; imperfect replication, war page, short shot, etc. To understand the cause and bring a solution, it is needed that check of changing in the cavity. This study can catch them. Data acquisition system about temperature and pressure distribution is settled and can get some data. From this research, other studies related with DAQ in cavity can start on the easier step.
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This study was carried out to analyze the effect of machinery house location on the stability of high efficiency gantry crane which can improve the productivity of the container transportation wok by reducing cycle time. The wind load was evaluated according to 'Load Criteria of Building Structures' enacted by the ministry of construction & transportation. The uplift forces of high efficiency gantry crane under this wind load were calculated by analyzing reaction forces at each supporting point. And variation of reaction forces at each supporting point was analyzed according to machinery house location.
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The effects of injection molding conditions on the uniformity and brightness of light guide plate(LGP) with micro-patterns were investigated in the present study. An injection molding system for stampers with mirco-pattern was designed and manufactured to perform experiment. Variations of injection molding speed, mold and melt temperature for LGP were considered in this work. Also, injection molding characteristics of LGP were investigated by numerical analysis using plastic injection molding commercial code. It was shown that injection molding conditions such as injection speed, melt temperature and mold temperature can have an effect on the uniformity and brightness of light guide plate.
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In this paper, we developed an algorithm of generating cam contour curve for hinge mechanism of folder-type mobile phone. The main feature of this hinge mechanism is that we can operate uniform torque to open or close the mobile phone. We divided the opening or closing intervals of the cam into finite sub-intervals, and then we determined the cam contour curve of each sub-interval as a parabolic curve. Finally, these finite parabolic curves form the total cam contour. We can design single cam, which composed moving cam with contour curve and fixed cam that plays only roller, and twin cam with contour curve that is made up the pair of two cams symmetrically.
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In this study, as a basic research to improve braking efficiency of a ventilated disk brake, we carried out a thermal stress analysis. From analysis result, we knew that a maximum mechanical stress by braking pressure and friction force is applicable to 5 percent of yield strength and has no effect on a fatigue life's decrease for brake disk material. While, a maximum thermal stress by frictonal heat is applicable to 43 percent of yield strength and locates on a friction surface. So, we have found that a thermal stress is the primary factor of crack initiation on a friction surface of disk brake
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In modern Automobile Engineers, Modularize of parts is developing tendency that is more effective manufacture system and maintenance, and it also can be bring down the production cost. In this study will expect faults of mold and find the optimum of Casting Condition from the Simulation software (Z-CAST), tensile specimen is attempted for define the basic properties and process condition. In reasult, Diecasting of Seat Motor Housing is expected to be best fitted in Works.
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Recently many countries have concentrated their effort on the port automation, in order to be the Hub-port, that the Ultra Large Container Ship could come alongside the Quay, in their region. As the magnitude of the container ship increase, that of the Quay crane increases from 50ton-class to 61ton-class more and more. The wind speed criteria to design the structures used in the port was upgraded from 20m/s to 40m/s due to change of the weather condition. Our laboratory could have the ability to design the wedge type rail clamp for 50ton-class Quay crane in 30m/s wind speed. Accordingly we analyzed the load condition of the Quay crane about 40m/s wind speed upgraded from 20m/s and designed the wedge type rail clamp for 50ton and 61ton-class Quay crane.
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The microstructure of the parts made by the microcellular injection molding process influence properties, including impact strength, tensile strength and density of material. Microstructure of microcellular plastics is divided into core foaming region and solid skin region. Core foaming region is influenced by pressure drop rate, viscosity and cell coalescence. However, actual mechanism of the skin layers is not known despite its importance. The study on the skin layer is getting important because foaming rate of the plastics is determined by the thickness ratio of the skin layer. Especially in case of large molded part, control of the skin layer is needed because skin layer thickness is changed largely. Therefore it is necessary to study variation in skin layer thickness with processing parameters. In this paper, the influence of temperatures in the mold cavity on the skin layer s thickness was also addressed. In addition, the relationship between the temperature distributions across cavity of the mold with impact strength on parts made with the microcellular injection molding process was addressed. In addition, the method to predict the variation in skin layer thickness with mold temperature is discussed.
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The process equipment and remote handling for the deep geological disposal of high-level radioactive waste(HLW) should be checked prior to the operation in view of reliability and operability. In this study, the concept of virtual environment workcell is implemented to analyze and define the feasible disposal process instead of real mock-up, which is very expensive and time consuming. To do this, the parts of process equipment for the disposal and maintenance will be modeled in 3-D graphics, assembled, and kinematics will be assigned. Also, the virtual workcell for the encapsulation and disposal process of spent fuel will be implemented in the graphical environment, which is the same as the real environment. This virtual workcell will have the several functions for verification such as analyses for the equipment's work space, the collision detection, the path planning and graphic simulation of the processes etc. This graphic virtual workcell of the HLW disposal process can be effectively used in designing of the processes for the hot cell equipment and enhance the reliability of the spent fuel management.
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This paper presents analysis of dynamic characteristics of a high-speed milling spindle with a drawbar and a built-in motor. The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. In this system the shaft is usually assumed as a rigid rotor. In this paper, the modal characteristics of drawbar in high-speed milling spindle system due to supporting stiffness between drawbar and shaft and considering the mass and stiffness effects of the built-in motor's rotor are analyzed by numerical method. The result shows enough stiff supports must be provided between shaft and drawbar to prevent occurring drawbar vibration lower than the natural frequency of 1st bending mode of spindle. And considering the mass and stiffness of built-in motor's rotor is important thing to derive more accurate results.
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This study was aimed at evaluating the structural safety for rubber tired AGT system. Based on these, AGT system which was developed for first time in domestic is need to verify structural safety. So we measured the characteristics of guide-rail, switch rail, side wall in the constructed test track for rubber tired AGT system. Finally, all results of test showed that structural safety of the rubber tired AGT system.
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Fretting contact and fretting fatigue are known to occur in mechanical devices which have fasteners subjected to oscillatory tangential load. Theoretical studies on fretting contact have been focussed on simple geometries, such as cylindrical contact problem. Recently, the contact problem of a flat rounded punch has been solved theoretically. The purpose of this paper is to show that the results of finite element analysis for the fretting contact problem are nearly consistent with the theoretical solutions.
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All teeth on the cycloidal plate gear exist in the contact motion with rollers and the forces are interacted between roller gears with cycloidal plate gears. So, the contact forces and friction forces must be required to improve the accuracy in design procedures of cycloidal speed reducers. This paper presents a force analysis considered the friction effect approach derived by static force equilibrium condition, geometrical adaptation, instant velocity center method and relative velocity method. Finally, the paper develops CAD-program for the construction of the design automation using the proposed method.
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earning industry is high in terms of side of creation of the added value or progress of technology rightly hereupon. This research raises or designed multi-function handling robot that can make welding, assembly conveniently catching large size work waterRatio that robot occupies is low level worldwide fairly in susdension wire, electricity electron and neutralization learning industry and domestic industry of this is staying in average leve. Can speak that grafting of robotic machine and neutralization
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Unwanted vibrations are inevitably induced in other directions when pure unidirectional vibration motion is desired for the vertical scratching mechanism. Pure vertical vibration motion of the scratching machine can be obtained by driving identical two motors with symmetrically positioned eccentric unbalance masses. The desired optimal condition for driving pure vertical vibration for the scratching machine is assumed to be the resonance condition in that direction. Imposing the flexibility of the scratching machine in the horizontal direction, we can find out the amount of horizontal vibration component while maintaining the resonance in vertical direction. The desired stiffness in horizontal direction which produces the minimum vibration in horizontal direction are defined which can be used as a guide line to design the supporting structure of the scratching machine.
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The main function of Ball-Stop part is to operate power shift for vehicle with more than 5 ton when a driver changes gear using suitable force. This paper presents the implementation of a DFSS(Design For Six Sigma) for robust design of Ball-Stop part of power shift. The factors influencing Ball-Stop part performance is derived to find control factor. Based on this factor, contact force between head and detent pin analysis is performed to get optimal factor is analyzed and compared with contact force test result to verify reliability of design. This makes clear the reason why the proposed one is necessary and the role of DFSS.
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Vulcanized natural rubber was pulverized using a single screw extruder in a non-cryogenic Solid Shear Extrusion process where rubber granulates were subjected to high compressive and shear stresses. The producted particles had diameters ranging from 40 to 1200
$\{mu}m$ . A principle used in this paper was developed in Russia. The development method for producing a polymeric material powder consists in compressing said material by shearing the material during a pressure increase and cooling. Consecutive breakdown is carried out by shearing the material during the pressure decrease and cooling. -
The Heat exchanger to be used in the place of business that is presented an utility period comes to be long and the problem of the length of life shares by the manufacture course and using environment factor. Consequentl, it is came to the front problem of inspection, repair, exchange, the utility stopping, safety and confidence. As a result the possibility which the large safety accident can happen comes to be high. It leads mostly to the large accedent when the explosion accident happens. to keep this, The system which the regular period passes to disuse the structure is prepared but The phenomenon which Time and the strength characteristic of the material change, namely Deradation. but It can't be a preventable solution by accident to the damage. Consequentl, This research can take important role to prevent an every kind accident for domestic pressure vessel by evaluating the mechnical characteristic change of meterial, the structure safety and residual life etc.
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The disk cam mechanism cam produce a positive motion with a relatively few components. In the present paper a shape design of cam using the relative velocity method and the machining information analysis using the circular interpolation are introduced. In the first part of the paper a machining information at each point using the circular interpolation is taken. This study purposes the analysis method of the cutting error due to the moving path of the cutter, so that we can lead to the optimum design in a disk cam mechanism..
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System algorithms estimated by deterministic input may occur the error between predicted and actual output. Especially, actual system can't predict the exact outputs due to uncertainty and tolerance of input parameters. A single output to a set of inputs has a limited value without the variation. Hence, we should consider various scatters caused by the load assessment, material characteristics, stress analysis and manufacturing methods in order to perform the robust design or estimate the reliability of structure. The system design with uncertainty should perform the probabilistic structural optimization with the statistical response and the reliability. This method calculated the probability distributions of the characteristics such as stress by combining stress analysis, response surface methodology and Monte-Carlo Method and got the probabilistic sensitivity. The sensitivity of structural response with respect to inconstant design variables was estimated by fracture probability. Therefore, this paper proposed the probabilistic reliability design method for fracture of uncorved freight end beam and the design criteria by fracture probability.
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Although metal ball can be used as parts of bearing or metal filter, that is used by single product with solder ball or shot ball. Also, according as demand of metal ball of various diameter increase, processing property 솜 extension of coverage are important. Especially an optimal design of cutting roller was investigated for determining appropriate dimensions of components of manufacturing system. In this study, the effects of the diameter and the round radius of cutting roller were calculated and analyzed. We applied data of rigid-plastic FEM Simulation in basis design of equipment to solve these issues, and confirmed processing factor about metal ball manufacturing process that use cutting process of metal wire in this research
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The fatigue characteristic of a material or a structure is derived from fatigue tests of standard specimens. However test results of standard specimens are very different from those of real structures or components. Therefore, to calculate more accurate fatigue life, the geometrical effect and surface condition must be considered by comparing test results of standard specimens with those of real structures or components. Thus the object of this paper is to evaluate the fatigue characteristic of a real waterwork pipe by conducting fatigue tests with standard specimens and non-standard(plate-shaped) specimens of base metal and weld metal. Also, to evaluate fatigue characteristic based on life distribution, statistical fatigue characteristic was analyzed by the normal distribution and related data of P-S-N curve.
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In this paper we investigate characteristics of deflection for circular plate with the non-symmetric boundary condition that is the boundary condition partly supported along the width direction of plate according to the length change of supporting end. For two boundary conditions such as simple supported and completely clamped boundary conditions, this study derives the maximum deflection formula of the circular plate using differential equation of elastic curve, assuming that a circular plate is a beam with the change of width and thickness along the longitudinal direction. The deflection formula of circular plate is verified by carrying out finite element analysis with regard to the ratio of length of supporting end to radius of circular plate.
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In this research the energy degrader, which is the most fragile part of the security of a target, has been newly designed to improve the performance of the gas target. Also, the numerical analysis of the heat movement and mechanical movement during the operation of the target has been accomplished. The heat analysis and structure analysis which are using the cooling water flow and pressure in the energy degrader and the Nastran mediocrity finite element analysis program, has been considered with the heat movement and mechanical movement according to the current capacity of proton beam which determines the production yield of the radioactive isotope. Also the possible use range has been determined, and at the same time the most suitable running condition according to the current capacity of proton beam has been suggested.
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The hydraulic LSD which uses the principle of gear pump is packed with viscous oil in tight container. When a slip occurs on one wheel, the hydraulic LSD generates torque caused by high oil pressure in the container. In this study, two dimensional(2-D) side pinion gear model was developed for hydraulic LSD. Using that model the flow analysis was conducted to preestimate pressure distributions of the side pinion gear according to the variations in the design factors such as oil viscosity, gear gap and rpm. Then, applying the obtained pressure distributions on the side pinion gear, finite element analysis was conducted to evaluate the torque characteristics. From the analysis results, the torque characteristics according to the design factor variations were evaluated.
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Micro Cellular Plastics create a sensation at polymer industrial for lowering product cost & overcoming a lowering of mechanical intensity. This research is surface quality research of MCPs product Through surface rough measurement. This experiment is carried out according to injection speed control with the surface rough & Product surface quality are searched
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During demonstrations of a process conditioning spent nuclear fuels, it may be necessary to transport and handle Spent fuel road cuts from Post Irradiation Examination facility to Slitting device in The hot cell. It may be not easy to transport spent fuel rod cuts because rod cuts are high radioactive materials. For this purpose, we have developed a capsule for transporting and handling high radioactive materials. We have analyzed conditions of a hot cell and requirements of the device, designed and manufactured The prototype of the device, and done some performance tests. From the tests, it has been shown that transportation and handling without scattering nuclear material was smooth but the weight of capsule was heavy. These result will be reflected to a design of the improved transportation and handling device which will be used during demonstrations.
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An automatic target sensing and triggering system for small fire arms is proposed. The system consists of an optical collector, an infrared ray sensor responsive to human body temperature, an electric actuator and a trigger mechanism. TRIZ methodologies are used to develop solutions to several contradictory problems. Experimental results on the system performance is compared with predictions.
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Injection molding process is one of the processes that can mold plastic product as low cost. However, manufacturing process of automobile bumper mold has lots of trial and error. Especially, desiging of a huge mold such as bumper mold is needed to establish a design standard for runner system. In this study, CAE was conducted to observe the variation of melt-flow by changing runner and gate type in automobile bumper mold as preceding study for a standard design of runner system.
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Gear trains are used in many machinery for variable speed ratios. Typical shapes of gear trains are two categories: simple gear trains and planetary gear trains. Generally the methods of the design typical shapes are two way. One of the methods is trailblazing design and the other is selective design in available types. This paper presents the mechanism types when input rotating velocity and output rotating velocity are maintained for useful planetary gear reducers of twelve types. Also, this paper gives the applicable example about rotating velocity of the gear axis, carrier velocity and the organized gear specifications
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Many studies have been carried out to produce 3D features in the size range between
$10{\mu}m\~10,000{\mu}m$ , called Meso-scale. If these miniaturized systems have high relative accuracy and good volumetric utilization, it is possible to manufacture more complex and accurate shapes with various materials as well as there are advantages of reducing energy, space and resources. Due to imperfect components and misalignment in assembly, it is necessary to assess the accuracy of the miniaturized system itself to obtain high relative accuracy. Laser interferometers are widely used to measure geometric errors called as quasi-static errors. For miniaturized system, however, it is difficult to install the required accessories such as optics and the measuring range is limited because of the size of the system and also this method is very expensive. Moreover, it is impossible to measure each error component simultaneously. A new system to measure simultaneously multiple geometric errors is proposed using capacitance sensors. Each error was measured using capacitance sensors and a measurement algorithm was mathematically derived. The experiments show that the proposed measurement system can be used effectively to assess the accuracy of miniaturized system at a low cost. -
As the various manufacturing technology of optical glass is developed, the aspherical lenses are applied to many fields. However, It is still very difficult to manufacture glass lens because of the high cost and the short life of core. In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. In the glass mold lens, it has merits of high productivity and reproductivity since lens is manufactured by the only forming with high precision mold. The fabricating conditions for glass mold lens are glass surface that does not cause fusion, viscosity of 108-1013 poise for the
$0.2{\mu}m$ accuracy, and viscoelasticity for the roughness less than 100 angstrom. In this thesis, ultra-precision grinding characteristics of tungsten carbide for forming the aspherical glass lens core were studied and the result of it is applied to manufacture the tungsten carbide-base core of the glass lens used to the laser scanning unit and the camera phone. -
The electron beam machining provides very high resolution up to nanometer scale, hence the E-Beam writing technology is rapidly growing in MEMS and nano-engineering areas. For E-Beam machining,
$2^{nd}$ electron detector is required to see a machined sample at the stage. The$2^{nd}$ electron detector is composed of scintillator and photomultiplier with signal amplifier and high voltage power supplier. Since a photomultiplier tube is an extremely high-sensitivity photodetector, the signal light level to be detected is very low and therefore particular care must be exercised in shielding external light. In this paper, the design methodology of$2^{nd}$ electron detector and the image noise removal method are introduced. -
According to the demand of the high productivity, the interest of manufacturing skills is growing in industrial society. Especially the high speed spindle in machining center becomes important these days. The exchange time of the tool in machining center usually calls T-T(tool to tool) time. Detailly explaning, It is influenced by the unclamping time. Affecting factors of the unclamping time are various(the hydraulic system, drawbar mass, a flow meter, disc spring, a piston diameter, pipe diameters, and so on). In this study, we could find factors that decrease the unclamping time and verify it for softwares.(AMESim
$4.0^{(R)}$ & visual Nastran$4D^{(R)}$ ) -
High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evaluation of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.
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The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.
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This paper is concerned with spring back after sheet forming of bulk amorphous alloys in the super cooled liquid state. The temperature-dependence and strain-rate dependence of Newtonian/non-Newtonian viscosities as well as the stress overshoot/undershoot behavior of amorphous alloys are reflected in the thermo-mechanical Finite Element simulations. Hemispherical deep drawing operations are simulated for various forming conditions such as punch velocity, die corner radius, friction, blank holder force, clearance and initial forming temperature. Here, spring back by an instantaneous elastic unloading was followed by thermal deformation during cooling and two modes of spring backs are examined in detail. It could be concluded that the superior sheet formability of an amorphous alloy can be obtained by taking the proper forming conditions for loading/unloading.
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The plastic injection molding industry is increasing pressure to reduce the cycle time in order to improve the productivity. The time of a cooling die is a large part of the cycle time. The conformal cooling channels can reduce the cooling time effectively as compared with conventional production die. It is hard to make the die with a conformal cooling channel by the conventional method. This paper introduces the method of a conformal cooling channel manufacturing by the DMT (Direct Metal Tooling) that is a new technology.
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Air-operated valve(AOV) is one of principal valves that are using to control fluid flow in nuclear power plants. AOV is suffered from damage and malfunction by the abrasion, corrosion and vibration of valve parts under the long time operation. This mechanical trouble and malfunction of valve is critical for the safety of power plant. So a periodic diagnosis for safety of power plants is inevitable to guarantee the safety of the power plant. But depending on the type of the actuator and valve body, various types of AOV exist. In this study, It is developed the diagnostic system that users of power plants are easy to handle in this paper.
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The performance evaluation of AOV(air-operated valve) requires the processes to confirm the actuator system capability. It is necessary to evaluate the thrust of the air actuator for the margin evaluation. In this paper, to evaluate and analysis the air actuator, the performance test system and operating program are developed. This system is composed of several sensors such as pressure sensor, LVDT, and LoadCell which are used to get the data for evaluation. The LabVIEW was used for developing the operating program. The test system and operating program are proved through the actual test of the diaphragm actuator.
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Most of materials receive force in using, therefore, the characteristics of materials must be considered in system design not to occur deformation or destruction. Mechanical properties about materials can be expressed as responsible level of material itself under the exterior operation. Main mechanical properties is strength, hardness, ductility and stiffness etc. Currently, among major measure facilities to measure such mechanical properties, advanced indentation technique has focused in industrial areas as reason of nondestructive and easy applications for mechanical tensile properties and evaluation of residual stress of materials. This study is to find the optimum experimental condition about residual stress advanced indentation technique for accurate analysis of the welded joint of steel materials through indentation load-depth curve obtained from cruciform specimen experiment. Optimum selection was applied to the welded joint of real steel materials to give non-equi-biaxial stress state and compared with general residual stress analyzing method for verification.
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In this paper ZMP was considered in order to get a walking stability, so the gait in the stable domain was realized through putting the stability margin in the sole domain of a foot. It is assumed that the robot's legs have 12 joints to operate a open-loop drive and there was no external disturbance under walking phases, additionally, the robot is walking on the flat plane. It was observed that the robot's walking trajectory, locus of COM and ZMP after imposing the motion to each joint. For realizing the simulation considering ZMP and movement of mass center, it was checked if it is stable for the constraint robot model to walk in stability and the feasibility was estimated about its dynamic gait. Eventually it was shown that a constraint gait algorithm is able to realize. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.
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In this paper, proportional modulator which controls the second pressure of the pneumatic system was studied and proportional operating of modulator was gotten by two digital valves that have a fast dynamic characteristics and were controlled by PWM operating method. In order to more precision pressure control, this modulator consist of not only high speed two digital valves but also pressure sensor, measurement equipment and controller having a microprocessing function. In this study, for the development of the new proportional modulator, various research such as PWM control method, test equipment manufacturing, testing and evaluation were accomplished.
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Eddy current sensor is representative instrument measuring gap to base metal and sensing trouble in base metal. The existing eddy current sensor works as measuring variance of sensor coil's inductance. But, sensor coil have phenomenon that not only inductance but also real resistance varies in real action. Conductivity and Permeability are main variable in sensor coil's varying impedance(inductance, real resistance). By searching relationship between conductivity-permeability and sensor coil's impedance, eddy current sensor gain advantage of elevation of accuracy, removal of alignment to each base metal, and continuous sensing to varying base metal.
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The auto-collimation by using theodolite has been accomplished for the straight measurement and the horizontality adjustment. But according to the procedure of auto-collimation or composition of the measurement equipment, an error of the measurement can be occurred. Therefore, this paper accomplished the research for enhancement of measurement accuracy according to measurement procedure of auto-collimation. For that, it has been compared the study of the combination of several precise measurement equipment with using of several theodolite.
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In this study, we were developed an accuracy of the proposed two dimensional statical inclinometer what used a position sensitive detector(PSD) by an error analysis. The inclinometer consists of a laser source, a mass, an optic-fiber, and a PSD. The gravity direction on a base platform of the inclinometer is changed by an unknown inclination angle. And a laser spot is moved from the origin to another position of a PSD following a variation of an optical path by the gravity. These processes enable the inclinometer to estimate the inclination angle from distance information of the moving spot. A design methodology on the basis of a sensitivity analysis was applied to improve the measurement performance such as a full measuring range and a resolution. But it still has error factors, so we analyze the uncertainty of the inclinometer to evaluate the systematic errors from alignments, assembly error and so on. The experimental performance evaluation about the design objectives as a measuring range and a resolution was performed. And the validity and the feasibility of the design process were certified by an experimental process. Systematic errors eliminated to improve the accuracy of the inclinometer by the corrected measuring model from the calibration process between the inclination angle and the PSD position instead of the nominal measuring model. The ANOVA(analysis of variance) confirmed the effect of eliminating the systematic errors in the inclinometer. From these methodologies, the proposed inclinometer was able to measure with a high resolution(35.14sec) and a wide range(from
$-15^{\circ}\;to\;15^{\circ}$ -
The pipe which it uses from the nuclear power plant or factory by a long period use and a corrosive action the inside defect occurs on the inside. abstract here. The ESPI method is in order to investigate the laser light in the measurement object it will be able to measure the wide territory whole in once, does not receive an effect in direction of defect not to be, has the strong point it will be able to measure a change of place arrowhead real-time defect. It measured a inside defect of pressure vessel by using Out of plane ESPI and In plane of ESPI. It compared a each method result.
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The prediction of AOV(air-operated valve) performance is normally evaluated by the allowable opening thrust margin for the opening and closing stroke. However, it is not easy to carry out the dynamic test measurement for all the valves in the nuclear power plant due to the safety and operating conditions. The analysis of the available and required thrust for the valve is simulated as an alternate method to turn around this obstacle. The required air pressures to the stem displacement are discussed for differential valve pressure obtained by experiment. The result of the simulation is compared with that of the experiment. SIMULINK in MATLAB was used for the simulation and the results show good agreement with the actual test carried out with Fisher globe valve.
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Even though SMA actuators have high power to volume ratio, there exist disadvantages such as hysteresis and saturation. So the model identification for SMA actuators is very difficult. For the qualitative model identification, we described the behavior of SMA actuators using a so-called diagonal model, which can readily expect the turning point of an incomplete phase transformation. For the quantitative model identification, we developed the general dynamics of SMA actuators using the modified Liang's model. Using this dynamics we can describe the hysteresis and the saturation very well. It is also very important to notice that the modified Liang's model maintains a continuous martensite fraction at the change of the phase transformation but the original model cannot.
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Incorrect information on public sites can cause serious problem. One of relevant countermeasures against this problem is to detect of buried underground utilities in real time. Although there have been several method to detect of buried underground utilities, such as investigating of gravity and elastic wave and electric field, they have not been so efficient tools. Because it is too expensive and difficult to use. In this paper, magnetic sensors which could provide an easier and more efficient method are used to detect of buried underground utilities. Also fluxgate method of self detection are used. Input signal is used
$1\~10kHz$ frequency. Filtering and signal processing of output signal are used labview software. After experiment, detection system of buried underground utilities which used magnetic shows possibility of precise detecting of laying object based on theorectical analysis for electromagnetic field. -
For application to micro fluid control systems such as
${\mu}TAS$ (Micro Total Analysis Systems) and DDS (Drug Delivery Systems), it is very significant to handle precise and minute flow rates with low pressure pulsation. In this study, a novel valveless piezoelectric pump using peristaltic motion with three disk type PZT actuators is presented. The newly devised pump with an effective size of$70mm{\times}60mm{\times}55mm$ has three actuator layers connected in series from inlet to outlet. The PZT actuator has a maximum displacement of 240${\mu}m$ and a maximum force of 1.6 N. When the driving voltage for PZT actuators is sequentially applied with a certain phase shift, the pumping is performed by peristaltic motion of liquid volume. The working fluid is shut off without the driving voltage. Three methods for sequential driving are proposed and experimentally investigated. First and second methods utilize an intermittent sinusoidal waveform with phase shift of$90{\circ}\;and\;120^{\circ}$ , respectively. Third method uses a rectangular waveform with phase shift of$90^{\circ}$ . A controller with multi-phase shifter is designed and fabricated. Then, frequency and voltage-flow rate characteristics and load pressure-flow rate characteristics are experimentally investigated to verify the validity of the developed pump. -
Time Delay Control (TDC) method was proposed as a promising technique in the robust control area, where the plants have unknown dynamics with parameter variations and substantial disturbances are present. In this paper we concerns vibration control of rotor system using TDC. Based on the rotor system model, the TDC is designed, and the PD-controller is also designed for comparison. The simulation results show that the TDC is much robust than the PD-controller to the unknown dynamics with parameter variations and disturbances.
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This paper presents the steering control algorithm of an up and down motion robot using a quaternion. The up and down motion robot is to be moved on an irregular floor that can inevitably result in the errors of both position and orientation. Especially the orientation error should be compensated every work in order to adjust the misaligned values of current orientation to those commanded values. In this paper, we propose a new steering control algorithm between the two values by using a quaternion with spherical cubic interpolation. The proposed algorithm is shown to be effective in terms of vibration when compared to a conventional simple compensation without interpolation, by using
$MATLAB^{(R)}$ and$VisualNastran4D^{(R)}$ -
This work proposes a controller tuning method of a Hyundai 8608 robot in order to improve its performance. For this, we analyzed the control structure of the robot, and the functions of all the adjustable parameters in the robot controller with a reference 'NACHI Technical Report'. Through the analysis, we found out that 3 important parameters(VRRL, VRF, VRGIN) act like a conventional PID gains and other parameters are closely related to these 3 parameters. Conclusively, parameter tuning of these 3 parameters is enough in most cases of applications with other parameters fixed. The conventional PID tuning is performed to each joint of the test robot with Robot Performance Evaluation System(shown in our companion paper) so that the acceptable gain ranges for each joint are determined and then the robot performance tests are repeatedly done with the combination of the acceptable gains. Finally, the best combination is selected for its best performance. For the effectiveness of the proposed method, it was implemented on a Hyundai 8608 robot and its results are compared with the results of NACHI's Semi-Auto Tuning Method and the results which are done by a tuning expert with his eyes.
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A linear motor makes a long stroke by accumulating short steps, which is based on the quasistatic deformation of a magnetostrictive material in a magnetic field. It's also called as inchworm effect. The application areas of linear motors are an adaptive and active optics, X-Y positioning, precision alignment, etc. It is found that control of the frequency and current inputs are all that is necessary to control the speed handling ability of the linear motor. In inchworm mode, linear speeds of up to
$500{\mu}m/s$ are achieved resulting from the accumulation of$25{\mu}m$ steps at 1.4A. -
The automatic
$CO_2$ welding is a manufacturing process to produce high quality joints for metal and it could provide a capability of full automation to enhance productivity. Despite the widespread use in the various manufacturing industries, the full automation of the robotic$CO_2$ welding has not yet been achieved partly because the mathematical model for the process parameters of a given welding task is not fully understood and quantified. Several mathematical models to control welding quality, productivity, microstructure and weld properties in arc welding processes have been studied. However, it is not an easy task to apply them to the various practical situations because the relationship between the process parameters and the bead geometry is non-linear and also they are usually dependent on the specific experimental results. Practically, it is difficult, but important to know how to establish a mathematical model that can predict the result of the actual welding process and how to select the optimum welding condition under a certain constraint. In this research, an attempt has been made to develop an intelligent algorithm to predict the weld geometry (top-bead width, top-bead height, back-bead width and back-bead height) as a function of key process parameters in the robotic$CO_2$ welding. A sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters. -
An automatic cap-washing machine is developed for rinse and dry of synthetic resin cap which is used in spring water bottle. This machine should be achieved all processes washing and drying, array, transfer automatically. A cap is washed by an ozonized water and pure water first. Next, a cap is dried by a hot wind drying equipment. In this paper, structural and modal analysis for the cap-washing machine is carried out to check the design criterion of the machine. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. And a fictitious mass properties was used for the analysis of the machine. Finally, the machine performance is shown to be satisfactory.
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This paper reports on the development of the gripping system for automation of phone-camera module assembling. If manual assembling is shifted by automation, it will increase the fabrication speed and reduce the defective rate. In the gripping mechanism design, we needs self-adjustable passive mechanism that minimize the number of the parts. The self-adjusting system compensates the positioning errors that have been made in translations. And also we need gripper system that can be modules of parts. That makes it easy to change or repair the parts. The forces put on the objects is another considerable in the system. It must not cause dropping, breakage, scratch, and large deformation. So final target of this reaseach is how to develop the system that is speedy, small, simple, and safe
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Automatic nut sorting machine used to calculate the size of inserted nut and detect the black spot defection is introduced in this paper. Because most of farm products are imported from the underdeveloped countries, domestic farm products have no place to be sold in market. To overcome this critical situation, lowering the productivity cost is strongly demanded to compete with foreign corps. Imaged processed nut sorting algorithm is developed to the automatic nut sorting machine to remove the sorting time which takes lots of man power. This system is composed of mainly two parts, mechanical parts and vision system. The purpose of mechanical part is supplying the nuts automatically to make computer system capture the images of objects. Simplified mechanical system was assembled followed by 3D simulation by Pro/E design for the adaptive cost effects. Several image processing algorithms are designed to detect the spot defects and calculate the size of nuts. Test algorithm shows good results to the designed automatic nut sorting system.
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We have a plan to design a controller for electron beam manufacturing system. At first, we designed a controller for SEM. The controller consists of five parts (power source, beam controller, scanning controller, optic controller and main controller). Beam controller supplies pulse wave for generating high voltage and can monitor the status of high voltage instrument through emission current. Optic controller controls focus, spot size and image shift. Main controller transmits variables from operating program to each part and monitors the status of peripheral device.
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Typical small desktop robots have limied application due to their intrinsic feaures like friction, backlash, etc. However, a newly developed small gantry desktop robot needs smaller footprint and shows better performance in position accuracy, velocity, and acceleration. In order to achieve such results, synchronization control of two axes, position compensation methods in plane are suggested.
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The direct write FIB technology has several advantages over contemporary micro-machining technology, including better feature resolution with low lateral scattering and capability of maskless fabrication. Therefore, the application of FIB technology in micro fabrication has become increasingly popular. In recent model of FIB, however the feeding system has been a very coarse resolution of about a few
${\mu}m$ . Our research is the development of nano stage of 200mm strokes and 10nm resolutions. Also, this stage should be effectively operating in ultra high vacuum of about$1x10^{-7}$ torr. This paper presents the discussion and results of CAE of the 2 axes stages. we have estimated the stable static and dynamic characteristics for dual servo system. Therefore the 2 axes stages developed and future work are introduced at the end of the paper. -
It is not efficient and scarcely out of the question to use commercial expensive electron beam lithography system widely used for semiconductor fabrication process for the manufacturing application field of various devices in the small business scope. Then scanning electron microscope based electron beam machining system is maybe regarded as a powerful model can be used for it simply. To get a complete suite of thus proper system, column unit build up with electron beam gun head unit is necessarily required more than anything else to modify scanning electron microscope. In this study, various components included ceramic isolation plate and main body which are essentially constructed for electron beam gun head unit are designed and manufactured. And this electron beam gun head unit will be used for next connected study in the development step of scanning electron microscope based electron beam machining system.
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Due to increase of demands on safety and convenience for automotive vehicle, the use of DC motor, such as power window, seat adjusting, pedal adjusting, sunroof, electric shift motor and so on, is increasing rapidly in the whole world. Worm gear is an important part to transmit torque to another gear in gear mechanism of automotive DC motor. But with current forming process, it has some problems in manufacturing and the quality. Also, the characteristics of automotive parts such as price and mass-production limit the quality improvement. Recently several methods are used in order to reduce a worm screw machining time and to maintain precision. In this paper, we introduce whirling tool machining and side milling cutter machining as effective manufacturing method of worm screw and study on the cutting force of side milling cutter and whirling tool in worm screw machining.
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In this paper, a decoupled dual servo (DDS) stage for ultra-precision scanning system with large working range is introduced. In general, dual servo systems consist of a fine stage for short range and a coarse stage for long range. The proposed DDS also consists of a
$XY\theta$ fine stage for handling and carrying workpieces and one axis coarse stage. Its coarse stage consists of air bearing guide system and a coreless linear motor with force ripple. The fine has four voice coil motors(VCM) as its actuator. According to a VCM's nature, there are no mechanical connections between coils and magnetic circuits. Moreover, VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about$25mm^2$ . To break that hurdle, the coarse stage with linear motors is used to move the fine about 500mm. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. With MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. And for their movements without any frictions, guide systems of the DDS are composed of air bearings. To get precisely their positions, a linear scale with 5nm resolution are used for the coarse stage's motion and three plane mirror laser interferometers with 5nm for the fine's$XY\theta$ motions. With them, on scanning the two stages have same trajectories. The control algorithm is named Parallel method. The embodied ultra-precision scanning system has sub 100nm following error and in-positioning stability. -
In the future, a machine-tool will be more improved in the form of a knowledge evolution based device. In order to develop the knowledge evolution based machine-tool, this paper proposes the structure of standard M2M(Machine To Machine) and the scheme of agent communication in environment. The communication agent such as dialogue agent has a role of interfacing with another machine for cooperation. To design of the communication agent module in M2M environment, FIPA(Foundation of Intelligent Physical Agent) and ping agent based on JADE(Java Agent Development Framework) or FIPA-OS(Open Source) are analyzed in this study. Through this, it is expected that the agent communication can be more efficiently designed and the knowledge evolution based machine-tool can be hereafter more easily implemented.
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Cutting force and face roughness have the largest influence on precision of a structure or processing efficiency in cutting processing. Thus cutting force model and face roughness model are necessary for this interpretation. In this paper, tool path model and face roughness model which consider the blade number of a tool and a revolution speed of tool and workpiece in the worm processing using side milling cutter are presented. This model was used to forcast the cusp. Experimental results show that the predicted cusp coincides with experimental one.
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The purpose of this study is to investigate the bending process for manufacturing of sound pipe by 3 dimension bending machine. The arbitrarily-bended pipe is widely used in a heat exchanger system. The pipe should be formed precisely for assembling of heat changer. And, spring back effect and variation of the pipe thickness should be controlled effectively. We described the change of spring back amount and thickness variation of the pipe according to the change of bending radius and bending angle by FEM analysis. The analysis is adopted the elasic-plastic analysis and contact analysis on MARC software.
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This Paper describes the mathematical modeling and control of the tension and the speed of moving Bio-wrap in a wrap winding machine. In winding process, important control specifications include the regulation of wrap tension and velocity. In this research, a tension and velocity model has been developed for winding processes. A prototype winding system has been constructed, and the controller has been implemented in a real time PC-based environment. The tension control system is modeled a MIMO of the two-input and four-output system. The performance of the modeled system has been evaluated via simulation using MATLAB and experiments.
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This paper presents the acceleration optimization of a high-speed LCD (Liquid Crystal Display) transfer system for the minimization of vibration. To reduce vibration is one of key requirements for the dynamic control of a high-speed LCD transfer system. In this paper, the concept of finite jerk (the first derivative of acceleration) has been introduced for realizing input acceleration. The profile of finite jerk has been optimized using a genetic algorithm so that vibration effect can be minimized. In order to incorporate a genetic algorithm, the dynamic model of a LCD transfer system which is realized by using the
$ADAMS^{(R){$ software has been linked to the simulation system constructed by the$MATLAB^{(R)}$ . The simulation results illustrated that the duration of finite jerk can be optimized so as to minimize the magnitude of vibration. It has been also shown that the acceleration optimization with finite jerk can make the high-speed motion of a LCD transfer system result in low vibration, compared with the conventional motion control with trapezoidal velocity profile. -
As the various manufacturing technology of optical glass is developed, the aspherical lenses are applied to many fields. However, It is still very difficult to manufacture glass lens because of the high cost and the short life of core. In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. In the glass mold lens, it has merits of high productivity and reproductivity since lens is manufactured by the only forming with high precision mold. The fabricating conditions for glass mold lens are glass surface that does not cause fusion, viscosity of 108-1013 poise for the
$0.2{\mu}m$ accuracy, and viscoelasticity for the roughness less than 100 angstrom. In this paper, ultra-precision grinding characteristics of tungsten carbide for forming the aspherical glass lens core were studied and the result of it is applied to manufacture the tungsten carbide-base cores of the glass lens used to the laser scanning unit and the camera phone. -
Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC(Automatic Too Changer), which is core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), reliability for those components and real tests reliability through constructed reliability test-bed. It is expected that proposed methodologies will increase reliability for high speed line center.
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The color and structure of urban constructions is a factor of urban landscape and shows their characteristics. Hence the modern buildings with their materials and external appearance makes up the urban image. But still yet, it was not easy to evaluate the value of visual landscape of buildings with objective measuring method. Most of all, it depends on the subjective estimation of a few talented or high educated experts with a sense of beauty. In relation to this kind of problems, it was tried here in this study to analyse the human response of brain wave pattern (EEG) with use of SD method, while the tested persons watched the urban landscape constructed in a visual reality. The tested persons were 10 adult males and females with no color blindness and intact cognitive function. Light source with color filter was used for color environment in chamber room. The signal of EEG is analysed digitally and grouped into the
$\alpha$ and$\beta$ waves. The result showed that relative power of$\alpha$ wave ratio increased in natural landscape scenary clearly. From these results it was possible to evaluate the human response, which was affected by urban color and structure stimulation and it might be useful as an indicator of visual cognition amenity toward the design of urban construction environment. -
In this paper, three-dimensional finite element analysis have been performed to investigate the biomechanics of vertebroplasty in patient. In order to apply various properties of the spine, the functional relation between the well-known apparent density and HU(Hounsfield unit) from CT image were employed and thus real material property can be assigned to each element of FE model. The FE analysis showed similar results with the experiments. With this approach accurate analysis of the spine and the clinical application can be expected.
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In recent years, the importance of the characterization of fall for a fracture prevention system keeps increasing since fracture from a fall can lead to serious health problems. Fall is one of the major sources which increase morbidity in elderly people. In terms of the cost and the influence to the quality of life, the most serious injury with hip fractures is caused by falls. The traditional methods in characterizing fall patterns have been mainly by the epidemiological surveys. With surveys, the exact data of fall patterns can not been acquired. In this paper, we measured and analyzed with the parameters related to fall pattern such as velocities and accelerations during the motion of falls using 3D motion capture program. We acquired the parameters of the fall pattern of intentional and unexpected fall. The result showed that the variation of velocity and acceleration during fall was very important in characterizing fall pattern, which of vital importance for the development of a fracture prevention system and for the safety of the elderly
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We investigated the activities of autonomic nervous system during foot bathing. The effect of foot bathing was evaluated for four subjects by observing the characteristic of heart rate variability and bodily temperatures. The foot bathing was done with a commercial foot spa (Duches Co.) utilizing the four functional modes of the spa for two different temperatures of
$35^{\circ}C\;and\;40^{\circ}C$ . The four functional modes were clam, vibration, air bubbles, and both vibration and air bubbles. The experimental results showed that the temperature of foot and that of face right after foot bathing were not that different from each other. But, for heart rate variability, the activation of parasympathetic nerve showed distinctive increase at$40^{\circ}C$ of water temperature. In the analysis of heart rate variability for different functional modes, the change was not distinctive for different modes at$35^{\circ}$ of water temperature. However, at$40^{\circ}C$ , the activation of sympathetic nerve showed distinctive increases with the increase in the complexity of functional modes. -
The isometric area of the anterior cruciate ligament was calculated during knee flexion-extension. Flexion-extension motion data of the joint were obtained using Fastrak and a three-dimensional motion measurement system. A total of five subjects were seated on a flat table and the tibia sensor position was measured with the femur fixed on the table. A three-dimensional knee model was constructed using a graphic tool to simulate the knee motion. Twenty seven positions of the tibia region and forty two positions of the femur region were selected and the distances between the determined tibial and femoral points were calculated. Highly isometric areas were found and displayed as three dimensional aspects.
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The technology of emotion recognition is a crucial factor in day of ubiquitous that it provides various intelligent services for human. This paper intends to make the system which recognizes the human emotions based on 2-dimensional model with two bio signals, GSR and HRV. Since it is too difficult to make model the human's bio system analytically, as a statistical method, Hidden Markov Model(HMM) is used, which uses the transition probability among various states and measurable observation variance. As a result of experiments for each emotion, we can get average recognition rates of 64% for first HMM results and 55% for second HMM results
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In this paper, the control of a prosthetic arm using the flex sensor signal is described. The flex sensors are attached to the biceps and triceps brchii muscle. The signals are passed a differential amplifier and noise filter. And then the signals are converted to digital data by PCI 6036E ADC. From the data, position and velocity of arm joint are obtained. Also motion of the forearm - flexion and extension, the pronation and supination are abstracted from the data by proposed algorithm. A two D.O.F arm with RC servo-motor is designed for experiment. The arm length is 200 mm, weight is 4.5 N. The rotation angle of elbow joint is
$120^{\circ}$ . Also the rotation angle of the wrist is$180^{\circ}$ . Through the experiment, we verified the possibility of the prosthetic arm control using the flex sensor signal. We will try to improve the control accuracy of the prosthetic arm continuously. -
The Teakwondo is composed of the breaking, competition and poomsea. In the hand breaking, the breaking impact of human is affected by the breaking posture. In this paper, impact analysis of the human model for breaking posture is carried out. The LifeMOD is used in breaking modeling and simulation. The simulation model createsthe human model to hit and to grasp a pine board. For the breaking, the poomsea motion of the hand joint inputs the splines pass condition. As the results, the reaction of human joint is presented
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A quantitative evaluation of postural balance training using a virtual reality bicycle system was performed. In the experiment, the effectiveness of virtual reality bicycle system on postural balance training was analyzed with four male subjects in their twenties. The parameters measured during cycling were cycling time, average velocity, number of times subject deviated from path, and weight shift. Those parameters were evaluated for the quantification of the extent of control. We also measured the parameters on postural control capability after 5th trial and 10th trial in a balance testing system with a force plate to find out the effectiveness of the training. In the balance test with force plate, it was found out that the weight shift was almost zero and the deviation from the target trace reduced significantly after the training with the virtual cycle. The result showed that the virtual bicycle system was an effective system as a rehabilitation training device.
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A driver's emotion is a very important factor of safe driving. This paper classified a driver's emotion into 3 major emotions, can be occur when driving a car: Surprise, Joy, Tired. And It evaluated the classifier using Hidden Markov Models, which have observation sequence as bio-signals. It used the 2-D emotional plane to classfiy a human's general emotion state. The 2-D emotional plane has 2 axes of pleasure-displeasure and arsual-relaxztion. The used bio-signals are Galvanic Skin Response(GSR) and Heart Rate Variability(HRV), which are easy to acquire and reliable. We classified several moving pictures into 3 major emotions to evaluate our HMM system. As a result of driving simulations for each emotional situations, we can get recognition rates of 67% for surprise, 58% for joy and 52% for tired.
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Degenerative lumbar spinal stenosis(DLSS) is a disease inducing low back pain, leg pain, convulsion, numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degenerative of neighbor region after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design of the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified fixators using the finite element analysis(FEA). Displacement, stiffness and Von-Mises stress were found to have similar values to those obtained from the mechanical test and the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator.
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The butterfly valve has been used to control a flow effectively in the industrial because of its lightweight, simple structure and the rapidity of its manipulation. However, it is difficult to have the existing structural optimization using field analysis from CFD to structure analysis when the structure is influenced by fluid. This paper is evaluated the specificity to get the flow characteristic and stability of the butterfly valve using FEM and CFD. Also, it accomplished the shape optimization design using the orthogonal arrangement and characteristic function. Research result, a few experiments showed the optimal results of three dimensional structures to be multi-objective.
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Equal channel angular pressing has been employed to produce materials with ultra-fine grains that have high strength and high corrosion resistance properties. Along with the experiments, the finite element method has been widely performed to investigate the deformation behavior of specimen and the effects of process parameters of ECAP. In general, several steps of ECAP have been repeatedly executed. In this paper, the effects of sectional shape change have been investigated during ECMAP (RouteA, RouteC) with pure-Zr by using three-dimensional finite element analysis. The results have been compared with the experimental results.
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The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excellent price and strength. The sheet metal process with above characteristic is common used in industrial field, but in order to analysis irregular field problems the reliable and economical analysis method is demanded. Finite element method is very effective method to simulate the forming processes with good prediction of the deformation behaviour. Among Finite element method, The static-implicit finite element method is applied effectively to analyze real-size auto-body panel stamping processes, which include the forming stage. In this paper, it was focussed on the drawability factors on auto-body panel stamping by AUTOFORM with using tool planing alloy to reduce law price as well as high precision from Design Optimization of ide. According to this study, the results of simulation will give engineers good information to access the Design Optimization of die.
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This study evaluate the statical stability of the container crane with respect to the direction of wind load which is varied between
$0^{\circ}$ and$180^{\circ}$ and its average velocity is 40m/s. Using wind experimental data and a formula of wind pressure, we figured out the wind load needed to perform a finite element analysis. And we can obtain the variation of reaction forces at each supporting point according to the direction of wind load. -
A micro fluid actuator driven by electromagnetic force at MEMS(Micro Electro Mechanical System) level has been designed. The operation of the actuator was simulated in three steps. First, fluid flow analysis has been performed to determine the actuator load. With the load, dynamic behavior of the actuator structure has been analysed. Finally, fluid-structure interaction analysis has been performed to predict the performance of the actuator. To avoid excessive amount of computation, axisymmetric and plane strain 2-D models were used.
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An automated mechanical parking system with a dedicated multi-floor building has been studied for improvements. Among the major components of the system, study is focused on the trolly which is the most important to the overall reliability of the system. The trolley holds and moves a parked vehicle horizontally into a specified position for the next sequence of operations. Optimization of a trolly structure is presented for strength and simplicity. With optimization, the weight has been reduced by 30% with respect to the conventional design.
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In this work, the effects of orthogonal ribs on warpage of plastic structure through injection molding process were investigated. Three kinds of injection molds were prepared to perform injection molding experiments of orthogonal stiffened plastic plate. The warpage of each injection molded specimen was measured using 3D CMM. And plastic injection molding analysis with commercial code was performed for the presented model. Numerical results of injection molding analysis were compared with those of experiments. It was shown that orthogonal ribs have a significant effect on the warpage of the structure in both cases of experiment and numerical analysis.
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The tensile test is generally used to measure mechanical properties with conventional fracture test. This test is extremely certain method to measure Young's modulus, yield strength, tensile strength and so on. ASTM, by international standard, prescribes two classes of tensile tests in tubular products. One is method that specimens aren't done by any process with Tube-shape. The other is that specimens are made on process for C-shape. In this paper, we would like to present the new-shape specimens for the tensile test. The presented specimen's shape is that put two pieces of C-shape specimens together. Besides a load point and a support point are fixed like Tube-shape specimens. This shape of specimen has a difference that existing specimen is made on one-step process out this specimen is made on two-step process. This shape is considered that stress concentration phenomenon occurs at the reduced section if a specimen is made on one step process.
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This study is concerned with the relation between steelbelt and belt edge separation. Belt edge separation causes tire burst and threatens passenger's safety. For that reason, it is important to predict durability caused by belt edge separation first in tire structure design step. In this study, to predict belt edge separation, we suggest the prediction method of belt edge separation and evaluate the effect of steelbelt width on the belt edge separation using FEM. We study on analysis parameter also to do exact estimation about the shear behaviour of belt edge area.
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The purpose of this study is to compare the modal parameters of a newly developed soft golf club prototype, which is designed to be lighter than regular golf clubs, with those of a regular commercial golf club. The modal tests were performed with two kinds of boundary conditions. The first condition was free-free condition and the second was fixed-free condition. An impact hammer and a Fast Fourier Transform analyzer were used to obtain modal data. From the results, it was found out that the modal characteristics of the soft golf club prototype were close to those of the regular golf club although the weight of the soft club was lighter. Therefore, the soft golf club is expected to be able to convey similar feel to the golfers even with lighter weight. This would enable elderly golfers to swing easily with the soft golf club with same skill which they acquired with regular golf clubs but with reduced load to their muscles.
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In this paper, we are willing to prepare the reasonable optimization, Combinatorial Optimization and Genetic Algorithm. Thus we define position status of end-effect (or terminative link module) using promised form, (G, M(G), A(G), and so on.). For this preparing step, the reorganizing procedure of Link and Joint Module is necessary, like as enumerating the kinematically identical assembly group of several links and joints. Thus, we draw a G, directed graph in a first step. Because, directed graph contains the path information between adjacent Link Module and Joint Module. From the directed graph,G, we can incite the Incidence Matrix, M(G). The incidence matrix, M(G), contains the contact information of the Link (Joint) Module and the type of Link (Joint). At the end of this paper, we generalize the modular information as a matrix form, A(G). From this matrix, we can make a population of assembly status. That is the finial output of this paper.
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A aspheric lens is one a key point optical element in the optical industry. The feature of a aspheric lens is not to have the spherical aberration. A aspheric lens is also essential element for high-precision and light-weight in the optical machine. Generally it have been used in a tailor progression an aspheric lens modelling much. In this study we applied a lay back-tracer using a index of refraction to draw a creative aspheric lens. And we executed a comparison experiment for refraction situation of shape and straightness experiment to inspect the drawn aspheric lens in this study
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This study was aimed to prove the safety of rubber-tired AGT light rail vehicle, which was designed to have the redundant equipment for safety, so the experiment of this paper was operated in condition of malfunction which we made such as bake sequence test and momentary interruption test. The result can bes handled by Labview 7.0 and showed as the graph.
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This paper concerns stress distribution of the soft golf clubs using FEM. The identification of the stress distribution of the soft golf clubs used the finite element method using ABAQUS. The soft golf clubs which were designated is a new golf clubs to keep a good health for the elderly. To design the soft golf clubs, we concerns two main purpose ; First, our efforts concentrate to reduce the weight of the soft golf clubs. We considers the change of material and geometry of the golf club‘s head and shaft. Second, it is to increase the size and shape of 'sweet spot' of the soft golf club’s head face. To accomplish this purpose, we made the various type of the soft golf club's head. In this paper, we simulates putter models of the soft golf clubs. The pre-processing which generates the mesh of the model used HyperMesh with geometry data by CATIA ver 5.0 This paper compares the stress distribution of putter type which was loaded.