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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 28, Issue 12 - Dec 2011
Volume 28, Issue 11 - Nov 2011
Volume 28, Issue 10 - Oct 2011
Volume 28, Issue 9 - Sep 2011
Volume 28, Issue 8 - Aug 2011
Volume 28, Issue 7 - Jul 2011
Volume 28, Issue 6 - Jun 2011
Volume 28, Issue 5 - May 2011
Volume 28, Issue 4 - Apr 2011
Volume 28, Issue 3 - Mar 2011
Volume 28, Issue 2 - Feb 2011
Volume 28, Issue 1 - Jan 2011
Selecting the target year
Development of an Accuracy Simulation Technology for Mechanical Machines
Park, Chun-Hong ; Hwang, Joo-Ho ; Lee, Chan-Hong ; Song, Chang-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 259~264
Authors are carrying out a national project which develops an accuracy simulation technology of mechanical machines to predict the stiffness and accuracy of machine components or entire machine in the design stage. Analysis methods in this technology are generalized to achieve the wide applicability and to be utilized as a web based platform type. In this paper, outline of the project such as concept, aim and configuration is introduced. Contents of the research are also introduced, which are composed of four main research fields; structural dynamics, linear motion analysis, rotary motion analysis and control and vibration analysis. Finally, a future plan is presented which is made up with three stages for the advance toward an ultimate manufacturing tools.
Simulator of Accuracy Prediction for Developing Machine Structures
Lee, Chan-Hong ; Ha, Tae-Ho ; Lee, Jae-Hak ; Kim, Yang-Jin ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 265~274
This paper presents current state of the prediction simulator of structural characteristics of machinery equipment accuracy. Developed accuracy prediction simulator proceeds and estimates the structural analysis between the designer and simulator through the internet for convenience of designer. 3D CAD model which is input to the accuracy prediction simulator would simplified by the process of removing the small hole, fillet and chamfer. And the structural surface joints would be presented as the spring elements and damping elements for the structural analysis. The structural analysis of machinery equipment joints, containing rotary motion unit, linear motion unit, mounting device and bolted joint, are presented using Finite Element Method and their experiment. Finally, a general method is presented to tune the static stiffness at a rotation joint considering the whole machinery equipment system by interactive use of Finite Element Method and static load experiment.
Accuracy Simulation of the Precision Linear Motion Systems
Oh, Jeong-Seok ; Khim, Gyung-Ho ; Park, Chun-Hong ; Chung, Sung-Jong ; Lee, Sun-Kyu ; Kim, Su-Jin ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 275~284
The accuracy simulation technology of linear motion system is introduced in this paper. Motion errors and positioning errors are simulated using informations on the design parameters of elements of linear motion system. 5 Degree-of-freedom motion error analysis algorithm utilizing the transfer function method and positioning error analysis algorithm which are main frame of accuracy simulation are introduced. Simulated motion errors are compared with experimental results for verifying the effectiveness. Then, using the proposed algorithms, simulation is performed to investigate the effects of ballscrew and linear motor on the motion errors. Finally, the influence of feedback sensor position on the positioning error is also discussed.
Accuracy Simulation of Precision Rotary Motion Systems
Hwang, Joo-Ho ; Shim, Jong-Youp ; Hong, Seong-Wook ; Lee, Deug-Woo ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 285~291
The error motion of a machine tool spindle directly affects the surface errors of machined parts. The error motions of the spindle are not desired errors in the three linear direction motions and two rotating motions. Those are usually due to the imperfect of bearings, stiffness of spindle, assembly errors, external force or unbalance of rotors. The error motions of the spindle have been needed to be decreased to desired goal of spindle's performance. The level of error motion is needed to be estimated during the design and assembly process of the spindle. In this paper, the estimation method for the five degree of freedom (5 D.O.F) error motions of the spindle is suggested. To estimate the error motions of the spindle, waviness of shaft and bearings, external force model was used as input data. And, the estimation models are considering geometric relationship and force equilibrium of the five degree of the freedom. To calculate error motions of the spindle, not only imperfection of the shaft, bearings, such as rolling element bearing, hydrostatic bearing, and aerostatic bearing, but also driving elements such as worm, pulley, and direct driving motor systems, were considered.
Accuracy Simulation Technology for Machine Control Systems
Song, Chang-Kyu ; Kim, Byung-Sub ; Ro, Seung-Kook ; Lee, Sung-Cheul ; Min, Byung-Kwon ; Jeong, Young-Hun ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 292~300
Control systems in machinery equipment provide correction signals to motion units in order to reduce or cancel out the mismatches between sensor feedback signals and command or desired values. In this paper, we introduce a simulator for control characteristics of machinery equipment. The purpose of the simulator development is to provide mechanical system designers with the ability to estimate how much dynamic performance can be achieved from their design parameters and selected devices at the designing phase. The simulator has a database for commercial parts, so that the designers can choose appropriate components for servo controllers, motors, motor drives, and guide ways, etc. and then tune governing parameters such as controller gains and friction coefficients. The simulator simulates the closed-loop control system which is built and parameter-tuned by the designer and shows dynamic responses of the control system. The simulator treats the moving table as a 6 degrees-of-freedom rigid body and considers the motion guide blocks stiffness, damping and their locations as well as sensor locations. The simulator has been under development for one and a half years and has a few years to go before the public release. The primary achievements and features will be presented in this paper.
Quantitative Analysis of Effect of Shrink Fit in Cold Forging
Li, Qiushi ; Kim, Min-Cheol ; Jung, Dong-Chan ; Son, Yo-Hun ; Joun, Man-Soo ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 301~307
In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, magnitude of shrink fit, dimension of shrink ring, number of shrink rings, partition of die insert and clamping force on effective stress and circumferential stress are analyzed. It has shown that the number of shrink rings, magnitude of shrink fit, and Young's modulus of die insert material have strong influence on compressive circumferential stress in die insert but that the influence of the other design parameters is relatively weak.
Study on Machining Speed according to Parameters in Micro ECM
Kwon, Min-Ho ; Park, Min-Soo ; Shin, Hong-Shik ; Chu, Chong-Nam ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 308~314
In micro electrochemical machining (micro ECM), machining conditions have been determined to maintain a small side gap and to machine a workpiece stably However, machining speed is slow. To improve machining speed while maintaining the form accuracy, the paper investigates machining parameters such as pulse amplitude, duty ratio, pulse on-time, and the electrolyte's temperature and concentration. The experiment in this study shows that the electrolyte's concentration is the key factor that can reduce machining time while maintaining the form accuracy Micro square columns were fabricated to confirm the machining parameters' effects.
Development of Ultra-Precision Machining Technology for V-Shape Micropatterns with 32" Large Surface Area
Lee, Sung-Gun ; Kim, Hyun-Chul ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 315~322
High-accuracy micropatterns such as V-shaped microgrooves are increasingly in demand for various engineering areas. And the technical trend goes for large surface areas in precision machining technology. So micropatterns with large surface areas are expected to play an increasingly important role in today's manufacturing technology In this study, we focused on developing machining technologies. First, a machine vision system for precise tool setting is developed. Second, an on-machine measurement (OMM) system for large-area measurement is implemented. And also software for tool path generation and simulation is developed. With these technologies we fabricated large-surface micropatterns in an electroless nickel-plated workpiece with single-crystal diamond tools and a 32-in,
mold with tens of V-and pyramid-shaped micropatterns.
Design and Fabrication of a Step Height Certified Reference Material for Multi-probe Inspection Instruments
Maeng, Sae-Rom ; Jin, Jong-Han ; Buajarern, Jariya ; Kim, Jae-Wan ; Kim, Jong-Ahn ; Kang, Chu-Shik ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 323~329
Certified reference materials (CRMs) have been used to calibrate surface profilers for reliable measurements. In this paper, we present a newly designed step height CRM which has a step height pattern with two different widths and various special patterns for checking radial magnification, distortion of optical viewing systems, etc. Especially, it could be useful for multi-probe inspection instruments in the manufacturing lines. The fabrication was done by conventional optical lithography and dry etching process with optimized conditions. To verify the step height values, a white-light scanning interferometer was used with objective lenses having magnification of
. CRMs with nominal step heights of
were fabricated and the uniformity of these CRMs was evaluated to be less than 3 nm (
A Study on the Visual Odometer using Ground Feature Point
Lee, Yoon-Sub ; Noh, Gyung-Gon ; Kim, Jin-Geol ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 330~338
Odometry is the critical factor to estimate the location of the robot. In the mobile robot with wheels, odometry can be performed using the information from the encoder. However, the information of location in the encoder is inaccurate because of the errors caused by the wheel's alignment or slip. In general, visual odometer has been used to compensate for the kinetic errors of robot. In case of using the visual odometry under some robot system, the kinetic analysis is required for compensation of errors, which means that the conventional visual odometry cannot be easily applied to the implementation of the other type of the robot system. In this paper, the novel visual odometry, which employs only the single camera toward the ground, is proposed. The camera is mounted at the center of the bottom of the mobile robot. Feature points of the ground image are extracted by using median filter and color contrast filter. In addition, the linear and angular vectors of the mobile robot are calculated with feature points matching, and the visual odometry is performed by using these linear and angular vectors. The proposed odometry is verified through the experimental results of driving tests using the encoder and the new visual odometry.
A Scenario based Framework for System Setup and Scheduling in Reconfigurable Manufacturing Systems
Lee, Dong-Ho ; Kim, Ji-Su ; Kim, Hyung-Won ; Doh, Hyoung-Ho ; Yu, Jae-Min ; Nam, Sung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 339~348
Reconfigurable manufacturing system (RMS), alternatively called changeable manufacturing, is a new manufacturing paradigm designed for rapid change in hardware and software components in order to quickly adjust production capacity and functionality in response to sudden changes in market or in regulatory requirements. Although there has been much progress in hardware components during the last decade, not much work has been done on operational issues of RMS. As one of starting studies on the operational issues, we suggest a framework for the system setup and scheduling problems to cope with the reconfigurability of RMS. System setup, which includes batching, part grouping, and loading, are concerned with the pre-arrangement of parts and tools before the system begins to process, and scheduling is the problem of allocating manufacturing resources over time to perform the operations specified by system setup. The framework consists of 8 scenarios classified by three major factors: order arrival process, part selection process, and tool magazine capacity. Each of the scenarios is explained with its subproblems and their interrelationships.
Simulation-based Stamping Process Design for a Pulsator Cover of a Washing Machine with Ferritic Stainless Steel Sheet
Kim, Se-Ho ; Kim, Kee-Poong ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 349~356
This paper replaces a conventional austenitic stainless steel sheet to a ferritic stainless steel for the cost reduction of a pulsator cover of a washing machine. However, ferritic stainless steel has poor formability in comparison with austenitic one. The low formability of ferritic steel results in problems during stamping such as fracture, wrinkling, shape inaccuracy and so on. Design modification of the stamping tool is carried out with the aid of the finite element analysis for multistage stamping process of the pulsator cover. The simulation results show that fracture occurs on top of the product while wrinkles are generated by the excess metal near the wing part. Modification of the initial stamping die is performed to improve metal flow and to eliminate problems during the stamping process. Simulation with the modified design fully demonstrates that safe forming is possible without inferiorities.
Optimum Evaluation of Reinforcement Cord of Air Spring for the Vehicle Suspension System
Kim, Byeong-Soo ; Moon, Byung-Young ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 357~362
Air springs are prevalently used as suspension in train. However, air springs are seldom used in automobiles where they improve stability and comfort by enhancing the impact-relief, breaking, and cornering performance. Thus, this study proposed a new method to analyze air springs and obtained some reliable design parameter which can be utilized in vehicle suspension system in contrast to conventional method. Among air spring types of suspension, this study focused on sleeve type of air spring as an analysis model since it has potential for ameliorating the quality of automobiles, specifically in its stability and comfort improvement by decreasing the shock through rubber sleeve. As a methodology, this study used MARC, as a nonlinear finite element analysis program, in order to find out maximum stress and maximum strain depending on reinforcement cord's angle variation in sleeves. The properties were found through uniaxial tension and pure shear test, and they were developed using Ogden Foam which is an input program of MARC. As a result, the internal maximum stresses and deformation according to the changes of cord angle are obtained. Also, the results showed that the Young's modulus becomes smaller, then maximum stresses decrease. It is believed that these studies can be contributed in automobile suspension system.
Finite Element Analysis of an Ultrasonic Tool Horn for Pattern Forming
Seo, Young-Soo ; Park, Keun ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 363~369
In this study, a direct pattern forming process on a plastic film using ultrasonic vibration energy is investigated. A tool horn containing micro-patterns is attached to an ultrasonic power supply, and is used to press a plastic film with ultrasonic vibration in order to replicate micro-patterns on the surface of the plastic film. To replicate micro-patterns with high accuracy, the tool horn should be designed to allow only the longitudinal vibration, not the transverse vibration. For this purpose, the design of a tool horn is investigated through finite element analysis, from which the resulting natural frequency of the tool horn can be adjusted in the range of the ultrasonic power supply. The analysis result is then reflected on the optimal design and fabrication of the tool horn. The validity of the developed tool horn is discussed through pattern-forming experiments using the ultrasonic vibration of the developed tool horn.
Optimization of the Deflection for large Disk type Gear of Auto Phoropter
Jung, Tae-Sung ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 370~376
Recently, the application range of plastic gears is widely expanding by the development of engineering plastics with good mechanical properties. Plastic gears have excellent performances such as light weight, water resistance and vibration absorbing ability for metallic gears. In this study, the optimization of injection molding process was done for the large disk type plastic gears of auto phoropter. Design Of Experiment (Taguchi method) was adopted to find a tendency of molding conditions that influence the flatness of disk type gear. Four main factors for molding conditions were selected based on injection temperature, filling time, packing pressure and mold temperature. Also, Filling, packing and cooling analyses were carried out to evaluate Z directional deflection of large disk type gear by using the simulation software (Moldflow) based on the DOE. From the results, it was found that the injection temperature and packing pressure are the most sensitive parameters for the Z directional deflection of large disk type gears.
Process Design Program for Multistage Profile Drawing from Round Material
Kim, Sung-Min ; Lee, Sang-Kon ; Lee, Tae-Kyu ; Lee, Seon-Bong ; Kim, Byung-Min ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 377~382
Up to now, process design of multistage profile drawing from initial round material is performed through trial-and-error based on experience of industrial experts. This means the increase in production cost and excessive time consuming. In this study, process design program was developed for multistage profile drawing from initial round material. The program was made using VisualLISP. Therefore, the program can be operated by AutoCAD program. In order to verify the effectiveness of the program, two stage profile drawing process for producing heavy duty guide rail was design by using the program. In addition FE analysis and profile drawing experiment were performed. As a result, the program can be used in order to design profile drawing process design.
A Feasibility Study on the Cold Hollow Cathode Gas Ion Source for Multi-Aperture Focused Ion Beam System
Choi, Sung-Chang ; Kang, In-Cheol ; Han, Jae-Kil ; Kim, Tae-Gon ; Min, Byung-Kwon ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 3, 2011, Pages 383~388
The cold hollow cathode gas ion source is under development for multi aperture focused ion beam (FIB) system. In this paper, we describe the cold hollow cathode ion source design and the general ion source performance using Ar gas. The glow discharge characteristics and the ion beam current density at various operation conditions are investigated. This ion source can generate maximum ion beam current density of approximately 120 mA/
at ion beam potential of 10 kV. In order to effectively transport the energetic ions generated from the ion source to the multi-aperture focused ion beam(FIB) system, the einzel lens system for ion beam focusing is designed and evaluated. The ions ejected from the ion source can be forced to move near parallel to the beam axis by adjusting the potentials of the einzel lenses.