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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 9, Issue 4 - Dec 1992
Volume 9, Issue 3 - Sep 1992
Volume 9, Issue 2 - Jun 1992
Volume 9, Issue 1 - Mar 1992
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Counter-Pressure Deep Drawing and its Application in the Froming of Automobile Parts
Hiroyuki-Amino ; Kazuhiko-Nakamura ; Takeo-Naragawa ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 9~21
Sheet metal forming with hydraulic counter-pressure has several advantages compared with conventional drawing, such as higher forming limits, higher accuracy of formed parts and the achievement of complicated formed shapes. About 50 special press machines have already been used in Japan for manufacturing lighting reflectors, aircraft parts and automobile parts. This report descirbes the techniques and the equipment used in the application of process.
A Study on the Measurement of Fine Scratches by Scattering of Laser Light
Gang, Yeong-Jun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 22~28
This paper is studied about the method to measure the fine scratches on the mirror surfaces, such as the silicon wafer and magnetic memory disk by the optical measuring method. The theoretical background of this analysis is based upon the light scattering theory developed by Beckmann. In this analysis, the roughness in fine scratches is not considered because the aberage roughness is very small compared with the size of fine scratches. Empasis is on quantilaive method of fine scratches by non-contact method. Experiments are followed by the image processing system attached to the CCD Camera. As a results, I propose the new method to measure the size of the fine scratches from the parameters obtained by the computer simulation and experiments.
Analysis of Magnetic Flux Density in Electro-Magnetic Chucks
Kim, Cheong-Gyun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 29~35
The distribution of magnetic flux density of electro-magnetic chucks may clarify the clamping characteristics which are strongly related to the machining efficiency and machining accuracy in a surface grinder. Therefore the distribution of the normal and the tangential components of magnetic flux density has been analyzed theoretically. It appears that the normal and the tangential components of magnetic flux density increase as the ratio of the separator width to the pitch e/p decreases. The results seem to increase the uniformity and stability of normal component of magnetic flux density for the decreased e/p.
Development of a Robot Wrist for the Assembly of Chamferless Parts
Gwon, Dae-Gap ; Jeong, Chung-Min ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 36~43
In this paper, a robot assembly wrist, which is able to assemble chamferless parts, has been developed. The RCC (Remote Center Compliance) structure is used as a basic structure. 5 position sensors and 4 pneumatic actuators are installed additionally to measure the deformation of RCC structure and correct the errors actively. Due to the restricted direction of actuation, a decision rule which selects the suitable actuator according to the position sensor signals is needed. For this purpose, a neural network is used and it is experimentally shown that the nerual network overcomes system's nonlinearity. This paper presents fundamental experiment results for the insertion of parts with several clearance.
A Study on the Two-Dimensional Automatic Mesh Generation Programming
Jo, Myeong-Cheol ; Yu, Hyeong-Seon ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 44~51
This paper is concerned with the propram of the automatic mesh generation for 2-dimensional domain which contains the curved boundaries and holes. This program treats a new vertical-line drawing method. This method starts with 4-subdivisions of problem domain and the classification of the cross points of grid lines and boundaries. The new node is generated by the vertical line to the line connecting the two intersections of a boundary and two grid lines in gereral. And the node very close to the boundary is moved to the boundary. The automatic mesh generation composed of only rectangular elements is achieved by this procedure. The boundaries are piecewise-curves composed of lines, circles, arcs, and free curves. The free curves are generated by B-Spline form. Although there were some bad elements for the complex boundary, it was possible to obtain the acceptible rectangular elements for the given boundaries.
Development of Heat Flux Sensor Using Adhesive Type Film Gauge for Measuring Temperature
Han, Eung-Kyo ; Choi, Gue-Cheol ; Rho, Byung-Ok ; Park, Too-Won ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 52~60
In this study on the development of the heat flux sensor, unlike the common heat-flux sensor with thermocouple, the heat-treated adhesive-tupe film nickel-gauge was used in measuring temperature. The proposed its Ni-gauge is bound to be compatible with platinum gauge(Pt-Gauge) in its linearity. It is also considered to be cheap in economical sense. In the evaluation of it's performance, the numerical analysis is essential to investigate charateristics of proper sensor and the adequate analsis is depended upon boundary conditions and actual conditions. There are many types of heat flux sensor in the market, and adhexive type flux sensor is most common. In the present investigation, this type of heat flux sensor had been chosen. The figure of the sensor under consideration is an open cavity type, which is calculated numerically by SIMPLER algorithm. The temperature distributions of the sensor predicted by numerical calculation for steady and unsteady states are able to give the chacteristics of the adhesive type heat flux sensor(1st heat flux sensor) according to the heat flux. It means that the outvoltage, the sensitivity, and the performances of responsibility could be evaluated as a result. Through this analysis improved heat flux sensor(2nd heat flux sensor) could be predicted with the reflection of proper operating temperature(
) of the Ni-gauge.
A Study on the Dynamic Modelling of Bearing Joints in Machine Tools
Lee, Sin-Yeong ; Lee, Jang-Mu ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 61~68
To meet the requirements for accuracy, productivity and reliability of machine tools, it is necessary to evaluate the chatter-free machining performance and to improve the dynamic performance of machine tools. In order to perform dynamic design of machine tools reasonably and effectively, the joint parts must be modelled accurately because their characteristics affect significantly on the total characteristics of machine tool. In this paper, an approach which identifies the effect of joint parts on the performance of total machine tool structure was proposed. That uses the experimental modal analysis, the finite element method and the sensitivity analysis method. The effectiveness of this approach was confirmed by applying it to structures with bearing joints. And as a result of the application, the change of dynamic characteristics of bearing joints was indentified.
A Study on the Evaluation of Automation & Flexibility in Assembly Systems
Mok, Hak-Su ; Gang, Won-Cheol ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 69~80
This paper deals with the evaluation methods for flexible automated assembly systems based on characteristics of automation and flexibility. In this study, the degrees of automation and flexibility are calculated quantitatively as the means of evaluating assembly systems. The degree of automation is grasped wheter the detailed assembly flexibility can be calculated indirectly14 by the estimation of cost and time which are caused to adapt the changed environment of the assembly system. As a case study, an assembly system is evaluated for showing the procedures of the developed method.
Vibration Control of Flexible Linkage Mechanisms Using Piezoelectric Films
Choe, Seung-Bok ; Jeong, Jae-Cheon ; Gu, Bon-Gwon ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 81~91
A control methodology for suppressing the elastodynamic responses of high-speed flexible linkage mechanisms is presented by adopting the concept of smart structures featuring piezoelectric films. The dynamic modeling of the proposed mechanism is accomplished by employing a finite element formulation which accounts for dynamic motion in both inertial and elastic coordinates. The dynamics of piezoelectric actuators and sensors bonded on the original flexible structure are developed for one-dimensional beam in conjunction with the modal analysis. The linear optimal controller which consists of a feedback control law and a Luenberger observer is employed. Numerical simulation is performed to evaluate the improvement of elastodynamic responses.
A Study on the Robust Digital Tracking Control of a Robot with Flexible Joints
Kim, Jin-Geol ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 92~100
Determination of Surface Strains in a Tensile Test by Digital Image Processing
Kim, Jong-Ho ; N. Bay ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 101~107
Evaluation of the Stress Intensity Factor for a Crack in Bimaterial Plate by the Boundary Method
Kim, Sang-Cheol ; Im, Won-Gyun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 108~115
An Optimal Plane Strain and Axisymmetric Extrusions of Rate Sensitive Materials
Lee, Jong-Su ; Hong, Seong-Seok ; Jo, Nam-Chun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 116~121
The optimal extrusion process for the rate sensitive materials have been developed in this study. The preliminary designs of the die shapes have been carried out to maintain constant strain rate during extrusion and the upper bound approach has been applied to define the process variables (the die entrance velocity and the die length) including the rheology during deformation. The result for the axisymmetric extrusion process has been verified with rigid-viscoplastic finite element analysis. It has been confirmed that the optimal die has wider band of constant strain rate than the conical one does.
Defect Measurement of Graphites for High Temperature Application by AE Technique
Choe, Man-Yong ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 122~127
In this study, we investigated defects of graphite by three NDT methods which are ultrasonic testing at 5 MHz, micro-forused X-ray testing and AE testing. As the detection of AE signals generated from graphite tensile specimens, we calculated location of AE sources and compared them with UT and X-ray test results in detecting defects of several specimens, Acoustic emission testing could be applied to some graphites which have fine grains of a few tens of micrometer, but it was difficult to those in lager grain of few fo milimeter. Also, we could understand what kind of defects has affected on tensile fracture of graphite.
Development of an Automatic Noise Detection System for Factory Automation
Yoon, Kang-Sup ; Kim, Hyun-Gi ; Lee, Man-Hyung ; Lee, Kwon-Soon ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 128~137
An automatic noise detection system is developed to sense abnormal noises in operating a microwave electronic range. A noise detection method is presented which accounts for the effects of backgound and dynamic noises of the range. A recursive formula used as a noise estimator is a special case of the discrete-time Kalman filter in stochastic processes. Noise levels were measured using a noise acquisition processor in a closed room free of background noise, and detected signals were processes using a microcomputer. The results obtaines showed that the fault detection system should be fast in response to the data acquired and should be high in accuracy and reliability.
A Study on Adaptive Control of Cutting Process
Kim, Nam-Gyeong ; Song, Ji-Bok ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 2, 1992, Pages 138~144
Conventionally, model equation for cutting process has been used at adaptive control. But in this paper, the cutting force is discerned by piezo electric dynamometer and is controlled adaptively using fuzzy inferance so that the constant load feeding is possible. Main conclusions are as follows : (1) with proper design of fuzzy label, more active cutting force control is possible. (2) adaptive control is possible with only qualitative knowledge instead of model equation of cutting process.