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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
Editor in Chief :
Volume & Issues
Volume 11, Issue 6 - Dec 1994
Volume 11, Issue 5 - Oct 1994
Volume 11, Issue 4 - Aug 1994
Volume 11, Issue 3 - Jun 1994
Volume 11, Issue 2 - Apr 1994
Volume 11, Issue 1 - Feb 1994
Selecting the target year
선반용 고속주축계의 동특성 해석
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 5~12
Development of mean specific cutting pressure model for cutting force analysis in the face milling process
Lee, B.C. ; Hwang, J.C. ; Kim, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 13~25
In order to design and improve a new machine tool, there is a need for a better understanding of the cutting force. In this paper, the computer programs were developed to predict not only the mean specific cutting pressure but also the cutting force. The simulated cutting forces in X, Y, Z directions resulted form the developed cutting force model were compared with the measured cutting forces in the time and frequency domains. The simulated cutting forces resulted from the new cutting force model have a good agreement with the measured force in comparison with these resulted from the existing cutting force model.
An upper bound analysis for closed-die forging of spur gear forms
Park, J.C. ; Hur, K.D. ; Park, J.U. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 26~37
A kinematically admissible velocity field for the numerical analysis of closed-die forging process of spur gear is proposed. The velocity field is divided into three regions of deformation. In the analysis, the involute curve is approximated to be straight line and the upper-bound method is used to calculate energy dissipation rate. A constant frictional frictional factor has been assumed on the contacting surfaces. The effects of root diameter, number of teeth, and friction factor are determined on the relative forging pressure. The frictionless relative pressure is independent of root diameter for the same number of teeth, but increases with the number of teeth on a given root diameter. In the presence of friction, the relative forging presure increasing root diameter at the start of forging, but decreases with increasing root diameter in the processing of forging.
Dynamic behavior of boring bar with continuous system analysis
Kim, J.S. ; M.C. Kang ; Park, S.K. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 38~46
The vibration amplitude of boring bar is generally large at the tool tip, because it has the high length-diameter(L/D) ratio. A new dynamic cutting force model is presented by considering the change of shear angle under dynamic cutting. The boring bar is modelled as a cantilever with dynamic force acting at the tool end point. Based on this realistic continuous system model, the equation of motion of borring bar is solved by numerical computations. A good agreement is found between the proposed model and the experimental results.
The study of fatigue crack propagation behavior in the welding residual stress field by superposition method
S.H. Song ; Kim, H. ; J.S. Bae ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 47~57
This study investigates the crack propagation behavior to examine the effect of welding residual stress by the superposition method. Especially, as the crack propagation behavior is affected by the applied stress and the stress ratio in compressive residual stress filed, it is studied for three cases as follows; (1)
is smaller than l
is smaller than l
l in the later stage, (3)
is lager than l
l. The resuslts show that the superposition method is very useful in all the three cases of compressive residual stress field, but is inappropriate in predicting the crack propagation behavior in tensile residual stress field.field.field.
Sectional analysis of stamping processes using Equilibrium approach
Yoon, J.W. ; Yoo, D.J. ; Yang, D.Y. ; Lee, J.H. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 58~68
An equilibrium approach is suggested as an effective tool for the analysis of sheet metal forming processes on the basis of force balance together with geometric relations and plasticity theroy. In computing a force balance equation, it is required to define a geometric curve approximating the shape of the sheet metal at any step of deformation from the geometric interaction between the die and the deforming sheet. Then the geometic informations for contacting and non-contacting sections of the sheet metal such as the number and length of both non-contact region, contact angle, and die radius of contact section are known from the geometric forming curve and utilized for optimization by force balance equation. In computation, the sheet material is assumed to be of normal amisotropy and rigid-phastic workhardening. It has been shown that there are good agreements between the equilibrium approach and FEM computation for the benchmark test example and auto-body panels whose sections can be assumed in plane-strain state. The proposed equilibrium approach can thus be used as a robust computational method in estimating the forming defects and forming severity rather quickly in the die design stage.
A study on the characteristics of acoustic emission signal in dynamic cutting process
Kim, J.S. ; M.C. Kang ; Kim, D.W. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 69~76
AE(Acoustic Emission) signal is correlated to workpiece material, cutting conditions and tool geometry during metal cutting. The relationship between AE signal and cutting parameters can be obtained by theoretical model and experiments. The value of CR(Count Rate) is nearly constant in stable cutting, but when the chatter vibration occours, the value of CR is rapidly increased due to the vibration deformation zone. By experimental signal processing of AE, it is more effective than by RMS(Root Mean Square) measurement to detect the threshold of chatter vibration by CR measurement.
Automated Forming Sequence Design System for Multistage Cold Forging Parts
Park, J.C. ; Kim, B.M. ; Kim, S.W. ; Kim, H.K. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 77~87
This paper deals with an automated forming sequence design system by which designers can determine desirable operation sequences even if they have little experience in the design of cold forging process. The forming sequence design in the cold forging is very important and requires many kinds of technical and empirical knowledge. They system isproposed, which generates forming sequence plans for the multistage cold forging of axisymmtrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning process. To recognize the geometry of the product section, section entity representation and primitive geometries were used. Section entity representation can be used for the calculation of maximum diameter, maximum height, and volume. Forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics (diameter, height, and radius), the product geometry is expressed by a list of the priitive geometries. Accordingly the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. Based on the results of forming sequence, process variables(strain, punch pressure, die inner pressure, and forming load) are determined.
A local path planning algorithm for free-ranging mobil robot
Y.Y. Cha ; D.G. Gweon ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 88~98
A new local path planning algorithm for free-ranging robots is proposed. Considering that a laser range finder has the excellent resolution with respect to angular and distance measurements, a simple local path planning algorithm is achieved by a directional weighting method for obtaining a heading direction of nobile robot. The directional weighting method decides the heading direction of the mobile robot by estimating the attractive resultant force which is obtained by directional weighting function times range data, and testing whether the collision-free path and the copen parthway conditions are satisfied. Also, the effectiveness of the established local path planning algorithm is estimated by computer simulation in complex environment.
Dynamic analysis of spindle system with magnetic coupling(1)
Kim, S.K. ; Lee, S.J. ; Lee, J.M. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 99~105
In this study, the transverse and the torsional vibration analyses of a precision dynamic drive system with the magnetic coupling are accomplished. The force of the magnetic coupling is regarded as an equivalent transverse stiffness, which has a nonlinearity as a function of the gap and the eccentricity between a driver and a follower. Such an equivalent stiffness is calculated by and determined by the physical law and the calculated equivalent stiffness is modelled as the truss element. The form of the torque function transmitted through the magnetic coupling is a sinusoidal and such an equivalent angular stiffness, which represents the torque between a driver and a follower, is modelled as a nonlinear spring. The main spindle connected to a follower is assumed to a rigid body. And then finally we have the nonlinear partial differential equation with respect to the angular displacements. Through the procedure mentioned above, we accomplish the results of the torsional vibration analysis in a spindle system with the magnetic coupling.
Construction of a knowledge-base for safety standards to support the design of household electrical appliances
Lee, H.S. ; S.H. Han ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 106~113
Household electrical appliances should be designed to satisfy safety standards. An expert system is implemented to support the design process. The general-purpose expert system shell. ART-IM which is running under MS-DOS environment, is used to construct the knowledge-base. A set of rules has been extracted from the EN 60 335-1 that is British standard specification for the safety of household and similar electrical appliances. The main focus of this paper is on codes that have systematic and mormative structures. The internal structure of the safety standard is analysed to improve the process of rule extraction.
A study on the thermal-mechanical fatigue life prediction of 12 Cr steel
J.S. Ha ; Kim, K.Y. ; H.T. Ahn ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 114~125
Fatigue behavior and life prediction method were presented for themal-mechanical and isothermal low cycle fatigue of 12 Cr forged steel used for high temperature applications. In-phase and out-of-phase thermal-mechanical fatigue test from 350 .deg. C to 600 .deg. C and isothermal low cycle fatigue test at 600 .deg. C, 475 .deg. C, 350 .deg. C were conducted using smooth cylindrical hollow specimen under strain-control with total strain ranges from 0.006 to 0.015. The phase difference between temperature and strain in thermal-mechanical fatigue resulted in significantly shorter fatigue life for out-of-phase than for in-phase. Thermal-mechanical fatigue life predication was made by partitioning the strain ranges of the hysteresis loops and the results of isothermal low cycle fatigue tests which were performed under the combination of slow and fast strain rates. Predicted fatigue lives for out-of-phase using the strain range partitioning method showed an excellent agreement with the actual out-of-phase thermal-mechanical fatigue lives within a factor of 1.5. Conventional strain range partitioning method exhibited a poor accuracy in the prediction of in-phase range partitioning method in a conservative way. By the way life prediction of thermal-mechanical fatigue by Taira's equivalent temperature method and spanning fartor method showed good agreement within out-of-phase thermal-mechanical fatigue.
Performance Management of Communication Networks for Computer Intergrated Manufacturing
Lee, S. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 126~137
Performance management of computer networks is intended to improve a given network performance in order for more efficient information exchange between subsystems of an integrated large-scale system. Importance of perfomance management is growing as many functions of the large- scale system depend on the quality of communication services provided by the network. The role of performance management is to manipulate the adjustable protocol parameters on line so that the network can adapt itself to a dynamic environment. This can be divided into two subtasks : performance evaluation to find how changes in protocol parameters affect the network performance and decision making to determine the magnitude and direction of parameter adjustment. This paper is the first part of the two papers focusing on conceptual design, development, and evaluation of performance management for token bus networks. This paper specifically deals with the task of performance evaluation which utilizes the principle of perturbation analysis of discrete event dynamic systems. The developed algorithm can estimate the network performance under a perturbed protocol parameter setting from observations of the network operations under a nominal parameter setting
Performance management of communication networks for computer integrated manufacturing Part ll: Decision making
Lee, Suk ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 138~147
Performance management of computer networks is intended to improve a given network performance in order for more efficient information exchange between subsystems of an integrated large-scale system. Improtance of performance management is growing as many function of the large- scale system depend on the quality of communication services provided by the network. The role of performance management is to manipulate the adjustable protocol parameters on line so that the network can adapt itself to a dynamic environment. This can be divided into two subtasks : performance evaluation to find how changes in protocol parameters affect the network performance and decision making to detemine the magnitude and direction of parameter adjustment. This paper is the second part of the two papers focusing on conceptual design, development, and evaluation of performance management for token bus networks. This paper specifically deals with the task of decision making which utilizes the principles of stochastic optimization and learning automata. The developed algorithm can adjuxt four timer settings of a token bus protocol based on the result of performance evaluation. The overall performance management has been evaluated for its efficacy on a network testbed.
Performance Investigation of a Cylindrical Valve Featuring Electro-Rheological Fluids
Kim, K.S. ; D.D. Jung ; Park, S.B. ; C.C. Cheong ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 148~157
A multi-cylindrical hydraulic valve incorporating with an electro-rheological(ER) fluid is developed in this study. Field-dependent Bingham properties of the ER fluid are exploited to devise the valve system which features fast system response as well as simple mechanism. The fast response is accrued from almost instant response characteristics of the ER fluid itself, and the mechanism configuration is simplified since no nechanically moving parts are required. The material properties of the ER fluids to be utilized for modeling of the proposed valve system are firstly tested with a couette-type electroviscometer. The design and manufacturing processes are then undertaken on the basis of model parameters. The performance characteristics of the valve system are evaluated in terms of pressure variations with respect to the intensity of employed electric fields and flow rates.
Volumetic Error Compensation of a Coordinate Measuring Machine using a Software Method
Park, J.H. ; Lee, E.S. ; S.H. Cho ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 158~164
A volumetric error compensation method was stueide with measuring systematic error of a Coordinate Measuring Machine(CMM). The volumetric error equations were proposed for a Moving Bridge type CMM. Using the error equations, error vectors in the measuring volume were corrected by a software method. The CMM was controlled by the compensation program separately in the measuring and moving function of the CMM proving. The linear accuracy of the CMM was measured by the Laser Interferometer and compared with the data before the volumetric error compensation. This method was proved as low cost and effective to reduce the systematic error of the CMM, as no hardware modification is required.
Analysis on Glass-Bead Type Retroreflector's Optical Characteristics
Lee, E.H. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 165~173
Retroreflector is different from other reflecting surfaces as it mades reflection in which radiation is returned in directions close to its incoming direction. Because of this characteristics, retroreflectors find many applications in traffic safety related areas. Retroreflectors are usually made using comer cubes, or partially coated glass beads. These glass beads can be made very small, so that they can be coated on sheets or mixed with paints. The design of glass type retroreflector depends on glass bead's shape and material, and its optical characteristics are related to the refractive index of glass. In this paper, a method of anlyzing glass bead type retroreflector's sptical characteristics with respect to shape and optica property of the glass, is presented. First, the coefficient of retroreflection, which is a measure of retroreflector's optical characteristics, is derived analytically using geometrical optics method. And the result is plotted using numerical methods. The results show good match with those obtained experimentally, which were supplied from a commercial retroreflector manufacturer.
A Study on the Performance Evaluation of Flexible Manufacturing Systems by Using Petri Nets
Kim, G.B. ; Lee, G.I. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 4, 1994, Pages 174~181
A FMS is a typical discrete event system exhibiting concurrency, asynchronicity and non-determinism. To represent a FMS with those characteristics, Colored and Timed Petri Nets is defined and the modeling procedure is provided in this paper. To analyze and evaluate the performance of a FMS, a simulation software is developed and applied to SNU FMS/CM Center. This software enables to detect the bottleneck machine and decide the optimal direction in case of the expansion of a FMS.