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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 13, Issue 12 - Dec 1996
Volume 13, Issue 11 - Nov 1996
Volume 13, Issue 10 - Oct 1996
Volume 13, Issue 9 - Sep 1996
Volume 13, Issue 8 - Aug 1996
Volume 13, Issue 7 - Jul 1996
Volume 13, Issue 5 - May 1996
Volume 13, Issue 4 - Apr 1996
Volume 13, Issue 3 - Mar 1996
Volume 13, Issue 1 - Jan 1996
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Machine Tool Technology; The Present and the Future(17)
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 13~27
A Study on the lmprovement of Accuracy in Manufacturing of Bourdon Tube
K.H. Na ; K.Y. Jhang ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 31~39
In this paper, the error and its sources in manufacturing of bourdon tube pressure gage was studied, and the method to reduce such errors was discussed. In more detail, the effects of parallelism of rollers, spring back, uniformity of radius curvature and the ratio of circumferential speeds of rollers were invesrti- gated. As a reselt, we could find out that the aprallelism of roller affected to the displacement error at the free end of gage and that the amount of spring back was closely related with the ratio of circumferential speeds of rollers. The uniformity of curvature radius was determined by the distance between bending rollers and it was comparatively uniform in the range above 30 .deg. C from the both sides of tube. Also, the ratio of circumfer-ential speeds of rollers was finded out as a very important factor giving severe influence on the creep or the hysteresis of bourdon tube.
An Automated Process Planning and Die Design System for Blanking of Stator and Rotor Parts
Park, J.C. ; Kim, M.M. ; Lee, S.M. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 40~51
This paper describes some research works of computer-aided design of blanking and piercing progressive die for stator and rotor parts. An approach to the system is based on knowledge based rules. The deveolped system is composed of six modules such as main program, input and shape treatment, production feasibility check, strip layout, die layout and drawing edit module. Using this system, design parameters ( geometric shapes, die and punch dimensions and dimensions of tool elements) are determined and output is gen- erated in graphic from. Knowledges for tool design are extracted from the plasticity theories, handbooks, relevant references and empirical know-hows of experts in blkanking companies. The developed system provides powerful capabilities for process planning and die design of stator and rotor parts.
Development of Discontinuous Grinding Wheel with Multi-Porous Grooves(I) -Design, Manufacture and Grinding Characteristics of Discontinuous Grinding Wheel-
Kim, J.D. ; Jin, D.X. ; Lee, Y.S. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 52~59
Conventionally, grinding of stainless steel, aluminium ally, copper alloy, and titanum alloy are difficult to obtain the high quality finish, because they have the mechanical properties such as low hardness, high toughness which result in the loading of wheel and the poor surface finish. Inorder to perform the grinding operations for these sorts of materials easily, the discontinuous grinding wheel with multi-porous grooves has newly been developed. The multi-porous grooves were formed during wheel production. This discontinous grinding wheel increases the grinding performance. It is desirable to use the discontinuous grinding wheel when grinding materials wiht high efficiency and accuracy which is impossible by conventional wheels. In this paper, the constructing and manufacturing method of grinding wheel with multi-proous grooves are explained, and the grinding charateristics of discontinuous grinding wheel are also illustrate.
A Computer Aided Automatic Verification System for Mechanical Drawings Drawn with CAD System
Lee, S.S. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 60~71
Mostof existing CAD systems do not provide the advanced function for systematic checking of design and drafting errors in mechanical drawings. We have reported a computer aided drawing check system to single plane projection drawings made by a CAD system. This paper describes a checking method of dimensioning errors in mechanical drawings. The checking items are deficiency and redundancy of dimensions, input-errors in dimension figures and symbols, etc. Checking for deficiency and redundancy of global dimensions has been performed applying Graph Theory. This system has been applied to several examples and we have confirmed the feasibility of this checking method.
Effects of the Convector Plate Shape and the Atmospheric Gas on Characteristics of Heat Transfer in a Batch Annealing Furnace
S.H. Yoon ; Kim, M.K. ; Kim, D.S. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 72~79
In a BAF(Batch Annealing Furnace), various studies have been pursued in order to reduce energy consumption rate to improve productivity and to stabilize the properties of products. The purpose of this study was to investigate the effects of both the atmospheric gas and convector plate shapes on the augmentation of heat transfer. The use of hydrogen instead of nitrogen as an atmospheric gas, combined with high convection in the BAF, has shown that considerable increases in furnace out put and significantly improved material quality are attainable. Because convector plate shapes make the atmosheric gas easily flow density, high diffusivity and reducing character of hydrogen, a better heat transfer rates resulting in uniform material temperature distribution and improved coil surface quality can be achieved. Also, it was found that the closed convector plate took more time for the annealing cycle time than the other plate type(open-type)by about ten hours.
A Study on the Prediction of Fatigue Life in the Axi-symmetric Extrusion Die
Ahn, S.H. ; Kim, T.H. ; Park, J.C. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 80~87
The present paper will give some results of the fatigue behavior of typical axi-symmetric forward extrusion die. The extrusion process is analyzed by rigid-plastic FEM and the deformation analysis of extrusion die is conducted by elasto-plastic FEM. To approach the crack problem LEFM (Linear Elastic Fracture Mechanics) is introduced. Using special element in order to conside the sigularity of stress/ strain in the vicinity of the crack tip, stress intensity factor and the effective stress intensity factor is calculated. Applying proper fatigue crack propagation criterion such as Paris/Erdogan fatigue law and maximum principal criterion to these data, then, the angle and the direction of fatigue crack propagation is simulated. In result, it is proved that the simulated fatigue crack propagates in the zigzag path along the radial direction and fatigue life of the extrusion die is evaluated by using the computed crack growth rate.
Deep Drawing of Glass Fiber Reinforced Thermoplastic Composite
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 88~95
A Study on the Material Behavior of Glass Fiber Reinforced Thermoplastic Composite in Uniaxial Tension
Lee, J.H. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 96~101
Glass fiber reinforced polymeric composites hold considerable promise for increased use in low cost high volume applications because of the potential for processing by solid phase forming. Unfortunately, because of the wide variety of such materials, inherent bariability in properties, and complex temperature and strain rate dependence, large strain behavior of these materials has not been well characterized. Of particular importance is failure during processing due to localized necking instability, and it is this phenomenon that is primary focus of this study. The strain rate and temperature dependence is used to predict limiting tensile strains, based on Mackinack imperfection theory. Excellent correlation was obtained between theory and experiment, and the results are summarized in the limit strains as a function of temperature and stain rate.
Active Tension Control Using an ER Brake Actuator
Park, S.B. ; Kim, G.W. ; Cheong, C.C. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 102~111
This paper presents a proof-of-concept investigation on an active tension control using an ER (electro-rheological) brake actuator. Firstly, an ERF (electro-rheological fluid) which has an inherent reversible feature from Newtonian fluid to Bingham fluid upon applying an electric field is composed, and its property is tested to obtain intrinsic parameters of the Bingham model. An appropriate size of the ER brake is manufactured on the basis of the Bingham model, and dynamic characteristics of the brake are experimentally identified. After formulating a governing equation of motion of the tension control system, a sliding mode controller is designed to achieve a certain desired level of tension. Both simulation and experimental works are undertaken in order to demonstrate the efficiency and feasibility of the proposed active tension control method.
Control of Electromagnetic Accelermeter with Digital PWM Technique
Kim, J.H. ; J.H. Oh ; W.S. Che ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 112~119
Among the various type of accelerometer, the servo rebalancing type accelermoter can be suitable for Inertial Navigation System, because of its high sensitivity and good response in low frequency. In this paper, we proposed a new technology to control inductive tuype accelerometer utilizing digital PWM method. The new developed digital PWM control has special design scheme for transmitting measurement value to outer device in its servo ollp. So it has no quantized error of transforming outputs of sensors to digital domain. The quantized error may make serious problem in INS system, because outputs of sensor are integrated once or twice by digital computer and it happens every sensor reading times. Therefore, in order to get the accurate information such as displacement, it is necessary to measure accurately the input current. In addition, Digital Signal Processing needs digital data transmission, digital PWM method is adaptive for this purpose. We realized a practical circuit for digital PWM control, analyzed the stability of the circuit, and designed the controller etc. In this study, we solved many practical problem for this application, and got out good results.
A Study on the Analysis of Pressure Characteristics of Hydraulic Modulator for Anti-Lock Brake System
C.S. Song ; H.J. Yang ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 120~127
Anti-lock Brake System has been developed to reduce tendency for wheel lock and improve vehicle control during sudden braking on slippery road surfaces. This is achieved by controlling the braking pressure, avoiding wheel lock, while retaining handling and brake performance. This paper is concerned about pressurecharacteristics of hydraulic modulator. Experimental sets which is consists of hydraulic modulator, duty controller, pressure regulator, pressure senset is consuructed. System modelling and computer simulation are performed for comparison with experimental results. Brake wheel pressure are measured under various driving pulse. The result of experiment show fairly agreement with the simulation. As a result, it is known that wheel pressure is affected by duty ratio, orifice diameter through computer simulation.
Characterization and Control of Grasp Stiffness Based on Virtual Stiffness Model
Park, H.R. ; W.K. Chung ; Y.I. Youm ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 128~138
Based on the virtual stiffness model, the stiffness of a grasped object is characterized. Differing from the previous investigations, the effect of grasp force on the stiffness of a grasp is formulated in terms of additional stiffness, which is called additional stiffness in this paper, and it is addressed how this term affects the stability of a grasp. In addition, a method of controlling the stiffness of a grasp is proposed and validated by experiments using a two-fingered robot hand.
On Tap Geometry and Characteristics of Torque in High Speed Tapping
Park, M.S. ; J.B. Song ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 139~145
Tapping is one of the most widely used machining operations. There are several methodes of producing external screw threads, e.g. turning, milling with single or multiple cutter, rolling, and grinding, but the methods available for cutting enternal threads are less numerous, and for threads in small holes, tapping is employed almost exclusively. In this study, the tap with the various geometry has been developed in order to tap special workmaterial at considerably higher cutting speed than that of the conventional HSS tap. The experimental tests are run with various cutting speed by using a piezo type tool dynamometer to measure tapping torque. Tapping torque is affected by the design of the tap, which seems to be due to internal friction and shearing of the metal. It is clarified that the process of chip formation strongly depends on rake angle, relief angle, angle of twist.
Concurrent Engineering Approach to the Die Design of Metal Forming Process using Rapid Prototyping and Finite Element Analysis
Part, K. ; Yoon, J.W. ; Cho, J.R. ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 146~154
In this work, rapid prototyping and three-dimensional finite element analysis are simultaneously applied to the die design of metal forming processes. Rapid prototyping is a new prototyping technology which produces three-dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus(SLA), which is the most widely used rapidprototyping system, is introduced to manufacture the die set. For general preparation of STL file, which is the standard input file of rapid prototyping system, mesh data which are used in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are dffectively connected. A die set for spider forging and a clover punch for deep drawing section are manufactured effciently using SLA prototypes, and metal forming experiments are carried out using them. Comparing the result of experiments with that of analyses, the processes can be predicted and designed successfully.
Vibration and Position Tracking Control of a Smart Structure Using SMA Actuators
Park, N.J. ; Park, S.B. ; C.C. Cheong ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 155~163
This paper presents vibration and position tracking control of a smart structure using shape memory alloy(SMA) actuators. A governing equation of motion of the proposed structure is obtained via Hamilton's princeple. The dynamic characteristics of the SMA actuator are experimentally identified and incorporated with the governing equation to furnish a control system model. Subsequently, a sliding mode controller which has inherent robustness to external disturbances is formulated on the basis of the sliding mode conplacement, and also for the position tracking control of desired trajectories with low-frequency sine and square waves.
Development of Software for Determining Grinding Wheel Geometry and Setting Condition in End Mill Manufacturing
S.L. Ko ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 164~174
As tools for machining precision componants, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing dianeter, they are liable to deflect when machining and induce geometrical error and deterioration of surface roughness. To improve the stiffness and the sharpness of the cutting edge of end mill, a software for manufacturing end mills are developed. The program predicts the result of helical flute grinding and the configuration of cuting edge which is located in cylindrical surface. Furthermore to facilitate the manufacturing end mills using CNC grinding machine, the setting condition which satisfy the geometrical requirements like tool rake angle and stiffness are obtained.
A Study on the Point Placement Task of Robot System Based on the Vision System
W.S. Jang ; C.G. You ;
Journal of the Korean Society for Precision Engineering, volume 13, issue 8, 1996, Pages 175~183
This paper presents three-dimensional robot task using the vision control method. A minimum of two cameras is required to place points on end dffectors of n degree-of-freedom manipulators relative to other bodies. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras. Estimation model is developed based on a model that generalizes known three-axis manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameters estimated by the iteration method.