Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
Editor in Chief :
Volume & Issues
Volume 7, Issue 4 - Dec 1990
Volume 7, Issue 3 - Sep 1990
Volume 7, Issue 2 - Jun 1990
Volume 7, Issue 1 - Mar 1990
Selecting the target year
A Model for Thermal and Wear Crown at the Hot Strip Roll Mill
Park, Hae-Doo ; Kim, Jin-Wook ; Choi, Jai-Chan ; Baek, Nam-Joo ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 14~25
A model predicting thermal and wear crown in order to control strip crown and shape has been investigated at the hot roll mill. A basic equation of predicting wear crown was obtained experimentally whereas thermal crown was approximately analyzed by the integral method. The calculated result based on the accumulative model of basic eauation coincides with that measured under the real rolling conditions. The effect of wear corwn is also analyzed by the longitudinal feeding method of the work roll. The high frequency feeding method is recommended in removing local wear effectively.
A Study on the Computer-Aided Design of Dies for Hot Extrusion of Structural Shapes from Aluminum Alloys
Choe, Jae-Chan ; Kim, Byeong-Min ; Lee, Jin-Hui ; Jo, Hae-Yong ; Lee, Jong-Su ; Hong, Seong-Seok ; Jo, Nam-Chun ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 26~36
This paper describes the Computer Aided Design (CAD) of dies for direct hot extrusion of structural shapes such as Z's and U's from aluminum alloys. A simple analysis of the direct extrusion process is developed and used to formulate a disign procedure for determining the optimal shape of the extrusion dies. A computer software system has been developed to design flat-faced dies for non-lubricated hot extrusion process. This software is a system of computer programs which are written to logical design procedure. Computer programs are based on empirical and analytical relationships, as well as on established knowledge based system. In the interactive mode of operation, the reaults at various tages of the design process are plotted on a screen. At any stage, the designer can interact with the computer to change or modify the design, based on his experience. The output from the program is (a) the design of the flat-faced die, (b) information on extrusion load, reduction ratio, and other process variables, etc. The implementation of this CAD system is expected to (a) provide scientific basis and rationalize the die design procedure, (b) optimize extrusion variables to maximize yield and production rate, (c) improve utilization of existing press capacity, etc.
A Study on the Effect of Tip Radius of Diamond Stylus Machined by Ion Sputter in Surface Roughness Measurement
Han, Eung-Gyo ; No, Byeong-Ok ; Yu, Yeong-Deok ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 37~47
In accordance with the high precision of mechanical elements, it has been required to high precision in surface roughness measurement and, therefore, stylus tip radius is manufa- ctured less than 2 .mu. m through ion sputter machining. In this experiment, by suing ion sputter machined stylus pf fine tip, radius and lapping machined stylus, surface roughness of standard specimens, silicon wafer were measured and then Rmax, Ra, RMS value were investi- gatedaccording to the variation of tip radius of stylus. As a result, measuring error due to the variation of stylus tip radius in surface roughness measurement was decreased by using ion sputter machined stylus and also the measuring accuracy was improved. And the measuring variation of Ra, RMS calculated from correlation coefficient lager than 0.9 on the wave of short period and amplitude using ion sputter machined stylus of fine tip radius.
A Study on a Modal Parameter Estimation Algorithm
Hwang, Won-Gul ; Kee, Chang-Doo ; Kim, Jong-Yeop ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 48~55
A new curve fitting algorithm based on modal analysis is introduced for extracting the modal parameters from the measured frequency responses. To compensate the effect of cut-off frequency ranges the transfer function including residual mass and residual flexibility is employed. Model parameters are computed from the newly defined form of transfer function in a simple way. The accuracy of this algorithm is proved by applying to the 3 degrees of freedom model and vibration of cantilever beam.
A Study on Tool Design of Deep Drawing Using Personal Computer
Choi, Jae-Chan ; Kim, Byung-Min ; Huh, Man-Jo ; Kim, Seong-Weon ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 56~65
This paper describes a computer aided tool design system of deep drawing of cylindrical cups with or without flange by press. An approach to system is based on knowledge based system. The computer program has written in basic language with personal computer Knowledges for tool design are formulated from the plasticity theory, handbooks, experimental results and empirical knowhow of the field experts. The capabilities of developed system include 1) the selection of tool structure (with or without blank holder, single or double action, lift up or draw off type), 2) the design of tool elements(punch/holder, die/holder etc.) for the previous selected tool structure by the process planning output and the production quantity. The final output is generated in graphics form for design sheet.
A Knowledge-Based Computer Aided Process Planning System
Cho, Kyu-Kab ; Oh, Soo-Cheol ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 66~74
This paper presents a knowledge-based computer aided process planning system that automatically selects machine tools, machining operations and cutting tools and determines sequences of the machining operations for prismatic parts in die manufacturing. In the proposed system, parts are described by manufacturing features and grouped into part families based on the functions. Each part is repressented by a part frame which consists of basic data and manufacturing features. Knowledge for manufacturing is acquired from the domain expert and represented by frames. A decision model for selection of machine tools, machining operations and cutting tools and for determining sequences of the machining operations are developed by employing the Mealy machine in finite automata with output. The decision procedure and the order of priority which inputs manufacturing features into the Mealy machine are represented by rule for each part family. Backward chaining is used for the proposed system. The proposed system is implemented by using TURBO-PROLOG on the IBM PC/AT. A case study for the slide core is presented to show the function of the proposed system.
A Study on the In-process Detection of Fracture of Endmill by Acoustic Emission Measurement
Yoon, Jong-Hak ; Kang, Myung-Soon ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 75~82
Automatic monitoring of the cutting conditions is one of the most improtant technologies in machining. In this study, the feasibility in applying acoustic emission(AE) signals for the in-process detection of endmill wear and fracture has been investigated by performing experimental test on the NC vertical milling machine with SM45C for specimen. As the results of detecting and analyzing AE signals on various cutting conditions, the followings have confirmed. (1) The RMS value of acoustic emission is related sensitively to the cutting velocity, but is not affected largely by feed rate. (2) The burst type AE signals of high level have been observed when removing chips distorderly and discontinuously. (3) When the RMS value grows up rapidly due to the increase of wear the endmill are generally broken or fractured, but when the endmills fracture at the conditions of smooth chip-flow or built-up-edge(BUE) occurred frequently, the rapid change of the RMS arenot found. And it is expected that this technigue will be quite useful for in-process sensing of tool wear and fracture.
A Study on Compensation Method for Variable Loads in Electro-Hydraulic Servomechanism Using Load Pressure feedback
Kim, Jong-Kyum ; Lee, Jin-Kul ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 83~93
The characteristics of servo systems are desired to be independent for any unpredicted operational condition. The relation between input current and output flowrate of the servovalve is dependent on the load pressure and the idea of compensation using the load pressure feedback is fundamental theory in this paper. With this idea, this paper researches the performance improvement of hydraulic position control system. Static characteristics of compensated system is analyzed by means of analog computer simulation, digital computer simulation and experiment for nonlinear model and linearized model, respectively.
Design of a Computer Software for Pneumatic Circuits
Son, Sung-Yong ; Lee, Dai-Gil ; Kwak, Yoon-Keun ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 94~102
A computer software which can draw and analyze pneumatic circuits was developed for the purpose of introducing and educating pneumatic circuits to beginners in this field. The program was developed using Turbo Pascal and Turbo Pascal Graphix Toolbox and could be run on IBM PC, XT, AT and other IBM compatible computers with a Hercules Graphics Board. The program was defeloped to show sequential control characteristics and to show two stages(on and off) of the pneumatic actuators. Users may save much time in drawing complex pneumatic circuits and can also use this software to check whether circuits are property designed before constucting real pneumatic circuits.
A Study on the Stability of Geared Systems Subjected to Torsional and Lateral Instability
Ro, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 7, issue 3, 1990, Pages 103~114
Many high speed mechanical systems incorporate gearing for speed reduction. This study investigates the stability of mulit-rotor geared systems supported on oil film bearings taking into consideration the coupling between torsional and lateral dynamics. The emphasis of the study is on the analysis of the interaction between the combined torsional and whirl insta- bilities. The feasility of inducing a lateral and the torsional instability to neutralize an anticipated unstable condition is investigated. The possibility of suppressing the instabilities by controlling the parameters of the oil film bearings is also considered.