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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 16, Issue 12 - Dec 1999
Volume 16, Issue 11 - Nov 1999
Volume 16, Issue 10 - Oct 1999
Volume 16, Issue 9 - Sep 1999
Volume 16, Issue 5 - May 1999
Volume 16, Issue 4 - Apr 1999
Volume 16, Issue 3 - Mar 1999
Volume 16, Issue 2 - Feb 1999
Volume 16, Issue 8 - Jan 1999
Volume 16, Issue 7 - Jan 1999
Volume 16, Issue 6 - Jan 1999
Volume 16, Issue 1 - Jan 1999
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Optimal Design Analysis of Link-Mechanism and Development of Control Performance Estimation Program for Unbalanced Heavy-Loaded Drive System
Choi, Keun-Kug ; Lee, Man-Hyung ; Ahn, Tae-Young ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 7~13
The unbalanced heavy-loaded elevation-driving system is composed of link-mechanism, hydraulic cylinder and compensator for the static unbalanced moment of the load. Control and compensation of elevation-driving system is very difficult because these mechanisms imply highly nonlinear properties due to hydraulic fluid characteristics and mechanical rotation of link-mechanism. In this study, through the analysis of the link-mechanism, the optimal design of the link-mechanism is suggested. Also to estimate the control performance of the unbalanced, heavy-loaded servo-controlled system, modeling and simulation of nonlinear system are carried out. To prove the validity of performance estimation program, simulation results are compared with the experimental results. Both results are similar, therefore this program will be helpful to study the improvement of the system control performance.
Evaluation of the Product Complexity Considering the Disassemblability
Mok, Hak-Soo ; Kim, Sung-Ho ; Yang, Tae-Il ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 14~24
In this study, the product complexity is evaluated quantitatively considering the disassembly process of the product. To evaluate complexity of the product, we analyze the characteristics of the product and the disassembly process. And we determine factors, which influence on the complexity of the product in the main-disassembly and sub-disassembly. Considering each characteristics of part and subassembly. Evaluations criteria of complexity are determined. Using evaluation criteria of the complexity can be determined the complexity grade of the product, and then we show the total complexity of the product considering the disassembly process.
Control Gain Tuning of a Simultaneous Multi-Axis PID Control System by Taguchi Method
Lee, Ki-Ha ; Kim, Jong-Won ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 25~35
This paper presents a control gain tuning scheme for multi-axis PID control systems by Taguchi method. As an experimental set-up, a parallel mechanism machine tool has been selected. This machine has eight servodrives and each servodrive has four control gains, respectively. Therefore, total 32 control gains have to be tuned. Through a series of design of experiments, an optimal and robust set of PID control gains is tuned. The index of the sum of position error and velocity error is reduced to 61.4% after the experimental gain tuning regardless of the feedrate variation.
A study on the Rapid Tooling Using Metal Powder Filled Resin
Kim, Peom-Su ; Bae, Won-Byung ; Jeong, Hae-Do ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 36~44
The rapid Tooling technique is classified into two methods: one to directly utilize the model which was made by rapid prototyping technologies for dies, and the other to make a transferred type using the model as a master model and create dies and molds using it. In this study, the Al powder filled resin was made several mixed ratios and meshes sizes, and applied to slurry casting. And, variation of mechanical characteristics such as the shrinkage rate, the tensile strength, the elongation, the hardness, and surface roughness, are measured to compare. Consequently, as higher is the powder mixed ration and as smaller is the grain size of the power, the mechanical characteristics of the final mold are improved. Finally, the metal short fiber which can be fabricated easily and cheaply, if the self-excited vibration of an elastic tool, was also applied to slurry casting. It has been found tat the hardness gets higher, while the shrinkage rate lower, if mixed with short fiber.
Manufacturing of Product by Semi-Solid Forging
Park, Hyung-Jin ; Kang, Chung-Gil ; Kim, Byung-Min ; Choi, Jae-Chan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 45~51
The semi-solid forging is a new forging technology in which the billet is heated to the semi-solid state coexisting liquid and solid phase for making globular microstructure and subsequently formed. As the semi-solid forging is compared with conventional casting such as die casting and squeeze casting for the characteristics of its process, the product without inner defects such as gas porosity and segregation can be obtained and its microstructure is globular grain. Simutaneously, its mechanical properties are improved by globular microstructure and the lower temperature of the slug causes the cycle time of manufacturing to be shortened and the die life to be lengthened. As it is compared with conventional cold and hot forging, it is possible to minimize the equipment of production owing to a lower forming load and reduce the number of process by a followed treatment for complex shaped product. Therefore it is needed to confirm the quality of a semi-solid forged product by defining its characteristics quantitatively under these advantages. This paper investigates the formability of a master cylinder by its forming variables. And the microstructural characteristics and mechanical property of it is also studied.
Development of Investment Casting Technique using R/P Master Model
Im, Yong-Gwan ; Chung, Sung-Il ; Jeong, Hae-Do ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 52~57
Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.
Development of the Wheel Disc Spinning Machine
Kang, Jung-Sik ; Kang, E-Sok ; Lee, Hang-Soo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 58~65
The spinning machine has been developed for a bus and truck wheel disc which is manufactured by spinning process method. This machine has the mechanical structure with bed, 2-column, cross head, 2-vertical slide, 2-horizontal slide with forming roller, clamp slide and main spindle similar to large size vertical lathe. Main spindle attached the mandrel is rotated about 500rpm drived by 280kW power DC motor, and a rotating black material pressed on the mandrel with the clamp slide is spinformed by 2-forming rollers which are attached inner end of the 2-horizontal slides. The 2-vertical and 2-horizontal slides are actuated by the hydraulic cylinder which is controlled by the servo valve individially, and these servo valves are controlled by control signal of the CNC controller which is computed with position signal feedbacked from the encoder sensor. The developed machine can manufacture wheel disc of various section profile without mandrel change because section profile is easily modified using program editing in the CNC controller processor. The wheel disc manufactured by spinning process method has many advantages that the endurance is increased by 2 times and the weight is decreased by 30% compared with a conventional disc.
A Driving Simulator of Construction Vehicles
Son, Kwon ; Goo, Sang-Hwa ; Yoo, Wan-Suk ; Lee, Min-Cheol ; Lee, Jang-Myung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 66~76
Vehicle driving simulators have been used in the development and modification of models. A simulator can reduce cost and time through a variety of driving simulations in the laboratory. Recently, driving simulators have begun to proliferate in the automotive industry and the associated research community. This paper presents the hardware and software developed for a driving simulator of construction vehicles. This effor involves the real-time dynamic analysis of wheel-type excavator, the design and manufacturing of the Stewart platform, an integrated control system of the platform, and three-dimensional graphic modeling of the driving environments.
experimental Investigation of Noise and Vibration Phenomena of a Heavy-duty Truck at High-Speed Driving
Lee, Yang-Sup ; Han, Moon-Sik ; Cho, Hang-Won ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 77~82
Cutter Runout Elimination in End Milling through Two-Axes PI Force Control
Noh, Jong-Ho ; Hwang, Joon ; Liang, Steven Y. ; Chung, Eui-Sik ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 83~89
This paper presents the in-process runout compensation methodology to improve the surface quality of circular contouring cut in end milling process. The runout compensation system is based on the manipulation of workpiece position relative to cutter in minimizing the cutting force oscillation at spindle frequency. the basic concept of this approach is realized on a end milling machine whose machining table accommodates a set of orthogonal translators perpendicular to the spindle axis. The system performed that measuring the runout related cutting force component, formulating PI controlling commands, and the manipulating the workpiece position to counteract the variation of chip load during the circular contouring cut. To evaluate the runout compensation system performance, experimental study based on the implementation of two-axes PI force control is presented in the context of cutting force regulation and part surface finish improvement.
A study on the Development of a Driving Simulator for Reappearance of Vehicle Motion (I)
Park, Min-Kyu ; Lee, Min-Cheol ; Son, Kwon ; Yoo, Wan-Suk ; Han, Myung-Chul ; Lee, Jang-Myung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 90~99
A vehicle driving simulator is a virtual reality device which a human being feels as if the one drives a vehicle actually. The driving simulator is used effectively for studying interaction of a driver-vehicle and developing vehicle system of a new concept. The driving simulator consists of a vehicle motion bed system, motion controller, visual and audio system, vehicle dynamic analysis system, cockpit system, and etc. In it is paper, the main procedures to develop the driving simulator are classified by five parts. First, a motion bed system and a motion controller, which can track a reference trajectory, are developed. Secondly, a performance evaluation of the motion bed system for the driving simulator is carried out using LVDTs and accelerometers. Thirdly, a washout algorithm to realize a motion of an actual vehicle in the driving simulator is developed. The algorithm changes the motion space of a vehicle into the workspace of the driving simulator. Fourthly, a visual and audio system for feeling higher realization is developed. Finally, an integration system to communicate and monitor between sub systems is developed.
Probabilistic Remaining Life Assessment Program for Creep Crack Growth
Kim, Kun-Young ; Shoji, Tetsuo ; Kang, Myung-Soo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 100~107
This paper describes a probabilistic remaining life assessment program for the creep crack growth. The probabilistic life assessment program is developed to increase the reliability of life assessment. The probabilistic life assessment involves some uncertainties, such as, initial crack size, material properties, and loading condition, and a triangle distribution function is used for random variable generation. The resulting information provides the engineer with an assessment of the probability of structural failure as a function of operating time given the uncertainties in the input data. This study forms basis of the probabilistic life assessment technique and will be extended to other damage mechanisms.
An Equivalent Plate Model for the High-Frequency Dynamic Characteristics of Cylindrical Shells
Lee, Joon-Keun ; Lee, U-Sik ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 108~113
For cylindrical shells, the closed-form solutions are confined to the specific boundary and/or loading conditions. Though the finite element method is certainly a powerful solution approach for the structural dynamics problems, it has been well known to provide the solution reliable only in the low frequency region due to the inherent high sensitivities of structual and numerical modeling errors. Instead, the spectral element method has been proved to provide accurate dynamic characteristics of a structure even at the ultrasonic frequency region. Since the wave characteristic of a cylindrical shell becomes identical to that fo a flat plate as the frequency increases, an equivalent plate model (EPM) representing the high-frequency dynamic characteristics of the cylindrical shell is introduced herein. The EPM-based spectral element analysis solutions are compared with the known analytical solutions for the cylindrical shells to confirm the validity of the present modeling approach.
Stress Analysis of the Prestressed Dies by Using FEM
Yeo, Hong-Tae ; Choi, Young ; Hur, Kwan-Do ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 114~122
By using the FEM, a method for the stress analysis of the presented dies has been proposed. In this method, FEM and Lame equation are used for the analysis of the die insert and the stress ring, respectively. The proposed method includes the calculation of the contact pressure between the die insert and the stress ring. To show the validity, the proposed method has been applied to the simple test problem. The results of the stress analysis have been compared with the results of ANSYS, a commercial FE-code. Cold extrusion has been simulated by using the rigid-plastic FEM and the results of the deformation analysis have been used as the input of the die structure analysis. The stress states of the prestressed extrusion die have been obtained. The stress analysis of the die insert with stress rings has also been performed during extrusion.
A Study on the Development of Computer Aided Die Design System for Lead Frame, Semiconductor
Choe, Jae-Chan ; Kim, Byeong-Min ; Kim, Cheol ; Kim, Jae-Hun ; Kim, Chang-Bong ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 123~132
This paper describes a research work of developing computer-aided design of lead frame, semiconductor, with blanking operation which is very precise for progressive working. Approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from pasticity theories, experimental results and the empirical knowledge of field experts. This system has been written in AutoLISP on the AutoCAD using a personal computer and in I-DEAS Drafting Programming Language on the I-DEAS Master Series Drafting with Workstation, HP9000/715(64). Transference of data between AutoCAD and I-DEAS Master Series Drafting is accomplished by DXF(drawing exchange format) and IGES(initial graphics exchange specification) methods. This system is composed of five modules, which are input and shape treatment, production feasibility check, strip-layout, data-conversion and die-layout modules. The process planning and Die design system is designed by considering several factors, such as complexities of blank geometry, punch profiles, and the availability of a press equipment and standard parts. This system provides its efficiecy for strip-layout, and die design for lead frame, semiconductor.
Chip Disposal State Monitoring in Drilling Using Neural Network
, Hwa-Young ; Ahn, Jung-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 133~140
In this study, a monitoring method to detect chip disposal state in drilling system based on neural network was proposed and its performance was evaluated. If chip flow is bad during drilling, not only the static component but also the fluctuation of dynamic component of drilling. Drilling torque is indirectly measured by sensing spindle motor power through a AC spindle motor drive system. Spindle motor power being measured drilling, four quantities such as variance/mean, mean absolute deviation, gradient, event count were calculated as feature vectors and then presented to the neural network to make a decision on chip disposal state. The selected features are sensitive to the change of chip disposal state but comparatively insensitive to the change of drilling condition. The 3 layerd neural network with error back propagation algorithm has been used. Experimental results show that the proposed monitoring system can successfully recognize the chip disposal state over a wide range of drilling condition even though it is trained under a certain drilling condition.
Stiffness Analysis of Compressed Rubber Components for Anti-Vibration
Kim, Kug-Weon ; Lim, Jong-Rak ; Ahn, Tae-Kil ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 141~147
Optical disk technology with a laser beam for data recording and retrieval is one of the most promising route for high density information storage in multimedia era. As the storage density and data transfer rates are increased, mechanical issues, mainly noise and vibration, become critical. Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber components with complex shape and under pre-deformed state. In this paper, non-linear large deformations of a rubber mount for optical disk drive were investigated using the finite element method. A tension test of rubber material was performed, to calculate a strain energy function. According to the pre-deformed state, the variation of rubber mount stiffness were calculated and the reliability of numerical results were checked by compared with the measuring the deflection values. Also, the effects of the pre-deformed rubber mount on the system dynamic characteristics were investigated and the relation between the static stiffness variation of rubber mount and the natural frequence variation of system was discussed.
Dynamic Contact Analysis of Spur Gears
Lee, Ki-Su ; Jang, Tae-Sa ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 148~159
A numerical method is presented for the dynamic analysis of spur gears rotating with very high angular speeds. For an efficient computation each gear is assumed to consist of a rotating rigid disk and an elastic tooth having mass, and finite element formulations are used for the equations of motion of the tooth. The geometric constraint is imposed between the rigid disk and the elastic tooth to fix them, and contact condition is imposed between the meshing teeth of the gears. At each iteration of each time step the Lagrange multiplier and contact force are revised by using the constraint error vector, and then the whole equations of motion are time integrated with the given Lagrange multiplier and contact force. For the accurate solution the velocity and acceleration constraints as well as the displacement constraint are satisfied by the monotone reductions of the constraint error vectors. Computing procedures associated with the iterative schemes are explained and numerical simulations are conducted with the spur gears.
Simulation of Ground Surface by In-process Measurement
Hong, Min-Sung ; Choi, Woo-Seok ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 160~165
In surface grinding, the conditions of the grinding wheel give a significant effect on the ground workpieces comparing with other metal removal provesses. In this paper, to assist the development, a non-contacting optical method by the laser beam is introduced. The in-process measurement of scattering intensities has been made during surface grinding processes and the surface textures of wheel working surfaces are captured. Also, in order to determine the dressing time monitoring method of a grinding wheel, a three-dimensional computer simulation of the grinding operation has been attempted based on the contact mechanism and the surface-shaping system between the grinding wheel and the workpiece. The optimal dressing time is determined by the amount of the grain wear and work surface roughness.
Design and Performance Evaluation of Controller for Unstable Motion of Underwater Vehicle after Water Entry
Park, Yeong-Il ; Ryu, Dong-Ki ; Kim, Sam-Soo ; Lee, Man-Hyung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 166~175
This paper describes a design and performance evaluation of robust controller which overrides unstable motion and pulls out quickly after water entry of underwater vehicle dropped from aircraft or surface ship. We use 6-DOF equation for model of motions and assume parameter uncertainty to reflect the difference of real motion from modelled motion equation. we represent a nonlinear system with uncertainty as Takagi and Sugeno's(T-S) fuzzy models and design controller stabilizing them. The fuzzy controller utilizes the concept of so-called parallel distributed compensation (PDC). Finally, we confirm stability and performance of the controller through computer simulation and hardware in the loop simulation (HILS).
Decoupling Controller Design for the JINAMCHA by Using Command Generator Tracker and Eigenstructure Assignment
Kim, Joo-Ho ; Choi, Jae-Weon ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 176~182
In this paper, we consider a decoupling control and a servo control for the JINAMCHA of which the cart and the pointer is coupled very strongly. The right eigenstructure assignment(i.e. simultaneous assignment of eigenvalues and right eigenvectors) is used for decoupling the motions of the cart and the pointer. The CGT(Command Generator Tracker) is used for a servo control of the JINAMCHA. The performance of the proposed control scheme, that is the combination of the right eigenstructure assignment and the CGT, is evaluated by simulations. The results show that the proposed controller has better performance than the LQR with limiting properties and the conventional LQ servo.
A Study on the Hot Deformation Behavior and Dynamic Recrystallization of Al-5wt%Mg Alloy
Hwang, Won-Joo ; Cho, Jong-Rae ; Bae, Won-Byong ; Kang, Suk-Bong ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 183~189
A numerical analysis was performed to predict flow curves and dynamic recrystallization behaviors of Al-5wt%Mg alloy on the basis of results of hot compression tests. The hot compression tests were carred out in the ranges of 350 ~ 500
/sec to obtain the Zener-Hollomon parameter Z. The modelling equation for flow stress was a function of strain, strain rate, temperature. The influence of these variables was quantifield using the Zener-Hollomon parameter. In the modelling equation, the effects of strain hardening and dynamic recrystallization were taken into consideration. Therefore, the modelling stress-strain curves of Al-5wt%Mg alloy were in good agreement with experimental results. Finally, the dynamic recrystallization kinetics were illustrated through the inspection of microstructure after deformation.
Analysis of Chip-Tool Friction and Shear Characteristics in 3-D Cutting Process
Lee, Young-Moon ; Choi, Won-Sik ; Song, Tae-Seong ; Park, Tae-Joon ; Jang, Eun-Sil ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 190~196
In this study, a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool has been established. The edge of a single point tool including circular nose is modified to the equivalent straight edge, then 3-D cutting with a single point tool is reduced to equivalent oblique cutting. Transforming the conventional coordinate systems and using the measured three component of cutting forces, force components on the rake face and the shear plane of the equivalent oblique cutting system can be obtained. And it can be possible to assess the chip-tool friction and shear characteristics in 3-D cutting with a single point tool.
Design of Cellular Layout based on Genetic Algorithm
Lee, Byung-Uk ; Cho, Kyu-Kap ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 6, 1999, Pages 197~208
This paper presents an operation sequence-based approach for determining machine cell layout in a cellular manufacturing environment. The proposed model considers the sequence of operations in evaluating the intercell and intracell movements. In this paper, design of cellular layout has an objective of minimization of total material flow among facilities, where the total material flow is defined as a weighted sum of both intercell and intracell part movements. The proposed algorithm is developed by using genetic algorithm and can be used to design an optimal cellular layout which can cope with changes of shop floor situation by considering constraints such as the number of machine cells and the number of machines in a machine cell.