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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 10, Issue 3 - Sep 1993
Volume 10, Issue 2 - Jun 1993
Volume 10, Issue 4 - Mar 1993
Volume 10, Issue 1 - Mar 1993
Selecting the target year
한.일의 IMS기술개발사업과 공업소유권 Issue
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 7~13
Development of a control method using both electric and pneumatic actuators for a heavy load handing robot
Park, S.D. ; Jeong, K.W. ; Youm, Y.I. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 14~21
Pneumatic actuators have greater power to weight ratio than electric ones, but they have been rarely used as robotic actuators because of poor accuracy resulted from nonliearity of air. On the other hand, electric servo motors have glld controllability, but they have poor power to weight ratio. For the heavy load handling robot a combined actuating method was developed for vertical and horizontal axes of RISTBOT-ll which handles up to 250kgf load. In this paper, the control method is implemented and analyzed for the manufactured heavy load handling robot.
Remote control of Drum/Chute mechanism in a concrete mixer-truck
Lee, M.C. ; K. Son ; W.B. Jeong ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 22~29
A remote control system was developed in order to operate by push-buttons the conventional drum and chute components, which have been operated manually, in a concrete mixer-truck. As actuators, a hydraulic power unit was used for chute operations: two DC motors for drum operations. The devised drum controller consisted of three electric circuits : an analog proportional-integral control circuit, a drum acceleration circuit, and an emergency stop circuit. The remote control system was installed to be tested experimentally and then was evaluated to work successfully with a desirable accuracy.
Non-steady state finite element analysis of nonisothermal hot container extrusion through conical dies
Y.S. Kang ; K.Y. Yang ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 30~39
The study is concerned with the thermo-viscoplastic finite element analysis of nonisothermal hot container extrusion through conical dies. The problem is treated as a non-steady state incorporating the nonisothermal heat transfer analysis. The analysis of temperature distribution includes heat transfer though the boundary surface including conduction, convection and radiation. The analysis of heat transfer is decoupled with the analysis of deformation and the material interaction is considered through iteration procedure. The effect of important process parameters including die angle and extrusion ratio in the process is investigated. Due to the geometric feature for the container extrusion through conical dies, automatic remeshing is mandatory. Automatic remeshing is achieved by introducing the modular remeshing technique.
Analysis of profile ring rolling for rings having V-groove of trapezoidal protrusion by the upper-bound elemental technique
Y.H. Hahn ; D.Y. Yang ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 40~47
To diversify the area of application of UBET to the analysis of ring rolling which produces rings having more complex cross-sectional configuration, an element of triangular cross-section has been introduced and the corresponding kinematically admissible velocity field has been derived while considering the material flow between neighboring elements. The theoretical perdictions in roll torque and profile formation show good agreement with the experiments. The effect of process parameters such as feed rate and taper angle of the roll groove has been discussed.
Development of a tool management system
Kim, S.H. ; Kim, D.H. ; Lee, C.S. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 48~53
At present, the manufacturing industry is in a process of a great change. There is a demand for a variety of types and shorter product life. The change increases the number of different tools and frequencies of tool changes. For the most part, the tools are presetted and offset values are entered manually or via punched tapes to NC machines. Thus a large amount of capital is tied up in the tool area and considerable productive time is lost. Consequently, there is a need for improvement in tool management. This paper describes a computer controlled tool data management system which include: 1) tool identification with bar code. 2) computer aided management and updating of tool data. 3) tool data communication with tool presetter, CNC, etc.
A development of accuracy diagnostic system 2-dimensional circular interpolation of machining centers
Kim, J.S. ; S. Namgung ; M. Tsutusmi ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 54~65
The paper describes and alternative method based on a new idea to measure the circular movement of machining centers. ISO has employed three testing methods for the acceptance tests of machine tools; the first is a rotating one-dimensional probe method, the second is a two-dimensional probe and a master circular ring, and the third is a kinematic ball bar. The last two methods were proposed and introduced by W. Knapp and J. B. Bryan, respectively. The newly developed method is superior to above two methods; the rotating angle can be detected and the rotating radius is variable. Circular movement errors of machining centers were investigated by the analysis of data measured by R- .THETA. method. Followint observations are obtained 1) The errors which depend on positions, i.e., periodical errors by the pitch of ball screws, errors by compensation of backlash and errors by perpendicularity of X and Y-axis, were analyzed. 2) The errors which depend on NC control system, i.e., errors by the unbalance of position-loop-gaians, errors by velocity-loop-gains and errors by feed speeds, were quantiatively analyzed. 3) The method of extracting error information, which uses moving technique of averaging angle and fourier's analysis data mesured by the R- .THETA. method, was proposed.
An experimental study on the in-process measurement of case depth for LASER surface hardening process
Woo, H.G. ; Park, Y.J. ; Han, Y.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 66~75
This paper proposes a monitoring method for nondestructive and in-process measurement of the case depth in LASER surface heat treatment process. The method is essentially an eddy-current method, and measures sensing coil's electrical impedance which varies with the changes of the material microstructure due to hardening. To investigate te validity of the proposed method a series of experiments were performed for various hardning depths. The results show that the relationship between the eddy- current sensor output and the changes in case depth is almost linear. This indicates that the eddy-current measuring method can be used as one of the possible monitoring method for mesauring the hardened depth in LASER heat treatment processes.
Optimal design for face milling cutter by simulation
Kim, J.H. ; Lee, B.C. ; Kim, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 76~85
Based on the cutting force model, three-dimensional optimal design model was developed and optimal designed tool which is minimized cutting force is developed by computer simulation technique. In this model the objective function which is minimized resultant cutting force was used and the variables are radial rake angle, axial rake angle, lead angle of the tool. The cutting forces using conventional and optimal tools by simulation, are compared and analyzed in time and frequency domains. In time domain the cutting force of optimal tool in feed direction was more reduced and less fluctuated than that of conventional tool. Cutting forces of optimal tool in X-and Z-directions are shown a little increased than those of conventional tool. In frequency domain amplitude of insert frequency components of optimal tool in feed direction was more reduced than that of convent- ional tool. The amplitudes of insert frequency components of optimal tool in X-and Z-direction are a little increased than those of conventional tool. As the reduction of amplitude and fluctuations of the cutting force, Optimal tool is considered that tool life and surface roughness would be improved, and stable cutting would be expected.
Design and fabrication of force measuring system using build-up procedure
D.I. Kang ; H.K. Song ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 86~94
In heavy industries forces which are exceeding the range of available force standard machines have to be measured. Force measuring system using build-up procedure can be applied to measure large forces efficiently. In this study strain gage type force sensors are designed and fabricated, and the build-up force measuring system with 4.5 MN capacity using the developed force sensors is 0.03% or less over the range of 600 kN .approx. 1.5 MN and the force measuring system is less than 0.06% or less over the range of 500 kN .approx. 4.5 MN.
Dectection of tool breakage using multi-sensing system
Lee, J.J. ; Park, H.Y. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 95~103
In the manufacturing field, some traditional manufacturing and machining methods become weakened the productivity, the external competitive power, and accuracies of the products. In these point of view, the unmanned and intelligent manufacturing systems are proposed by some manufacturing companies. The real-time monitoring technology of the cutting tool conditions i.e. tool wear, tool breakage, crack, and chipping anre necessarily reauired to realize those system, especially. In this study, we constructed the multi- sensing system using the acceleration sensor, the current sensor, and the loadmeter of a machine tool. Also, we analyzed the nose breakage, the massive signal, and some monitoring features by means of the developed system.
A study on structure and separation orientation of fiber-reinforced thermoplastic sheet
Lee, D.G. ; K.H. Cho ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 104~113
Characteristics of fiber-reinforced thermoplastic sheet depend on the quantity and shape of fibers. During a molding process of composites, the fiber-maxtrix separation and fober orientation are caused by the flow during the molding process. As a result, the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation-orientation and molding conditions. The correlation between the separation and the orientation have to be clarified for designing the fiber structure. In this paper, the degree of nonhomogeneity which is a measure of the separation is obtained using one-dimensional rectangular shaped part compression molding. And the orientation function is defined and measured by the image processing using soft X-rayed photograph and image scammer. Correlation between the degree of nonhomogeneity and the orientation function is discussed.
Standardization of machining process for progressive press die
Lee, S.M. ; Lee, S.J. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 114~125
In the present study the newly developed CAD/CAM system is applied to the process of the molding design, machining for mini-sized and precise processive die, and the production of press-stamped parts. When the design of a die was completed by means of CAD, wire cut NC data were generated with the aid of a design drawing in the CAD system and then inputed into the wire cut machine, and with the aid of a hole chart which had been made for this purpose, all the data were classified into the categories of CNC milling, jig boring, jig grinding, and machine center, and then developing a program of generating NC data, errors in process were reduced and programming time was shortened. The program was developed by using Autolisp language which was built-in the CAD, and realizing the intergation of designing a die, generating and processing NC data directly by a designer, designing time and machinery processing time were shorted. And the traditionally required working time for design. NC program required 6 days of work becomes 4 days of work by using the developed CAD/CAM system so that the efficiency shows 150% of the reduction working time. The prpgram of the design of the automation a progressive die mold was developed in the PC-Class Autocad system, therefore development expense could be reduced, and the integration of the CAD/CAM of the progressive die mold with the standard DB being built could be realized.
Identification of motion error sources in NC machine tools by a circular interpolation test
S.W. Hong ; Y.J. Shin ; Lee, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 126~137
This paper presents an efficient method for the identification of motion error sources in NC machine tools by making use of the circular interpolation test, which is often used in estimating the motion accuracy of NC machine tools. Mathematical formulae are described for motion errors due to various kinds of error sources. Two identification formulae are proposed: one is based on the frequency analysis and the other is formulated with the weithted residual method. Motion error signal is classified into two patterns, mean errors(mean of CW and CCW test signals from mean errors). The sources of the mean errors are identified by using the frequency analysis technique and the sources of the deviation errors by the weighted residual formulaltion. A menu driven, user oriented, computer program is written to realize the full steps of the proposed identificationprocedure. Then, the identification method is applied to two NC machine tools.
A study on the construction characteristic of bath cryostat
Kim, G.Y. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 138~145
The bath cryostat of cryogenic apparatuses which are generally used to study physical phenomena under low temperature and ultra low temperature has been desigened and constructed. The practical use of the cryostat is verified by the measurement of the storage life of liquid heloum and liquid nitrogen vessels. The cryostat consists of triple structure of high vacuum environment in order to minimize the evaporation rate of liquid helium and liquid nitrogen by thermal conductivity and radiant heat. The minimum thickness which can stand against inner and outer pressures is calculated from considering the strength of the material.
A study on the stress Distributions and magnetic properties during Hot-pressing according to Strain Rate of Nd-Fe-B-Cu Alloys
Park, J.D. ; Jeung, W.Y. ; Kwak, C.S. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 146~153
Thd specimens were melited in high frequency induction furnace. The samples for measurements were prepared by machining cylinder of 9.5mm diameter and 15mm height. These samples were then hot-pressed according to strain rate ( .epsilon. ). These samples were decanned and cut out, and subsequently heat treated at 1000 .deg. C for 4hours. These were investigated for the change of microstructure, domain pattern, X-ray diffraction and magnetic properties. The stress distributions in the specimens during compressing process were calculated by a finite element method program(SPID). The calculated stresses were effective stress( .sigma.
), compressive direction stress( .sigma.
), and shear stress( .tau.
). These stresses were compared with the experimental data.a.a.
A Study on the Optimal Frequency for Precise Measurement of Fracture Velocity by Ultrasonic Fractography
Lee, B.S. ; E.K. Han ; C.S. Song ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 154~160
A mothod to decide the optimal frequency for the fracture velocity measurement by ultrasonic fractography is presented. A theoretical formula to decide the optimal frequency for ultrasonic fractography testing is made and it is compared with experimental value. According to the formula the optimal frequency is shown to be depending on the attenuation coefficient and size(width) of the specimen. In the case of PMA specimen with ligament 43mm the theoretical value for the optimal frequency is about 260 KHz and it is good agreement with experimental value.
A modeling of dynamic cutting force and analysis of stability in chatter vibration
Kim, J.S. ; M.C. Kang ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 161~169
The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is presented in order to predict the dynamic cutting force from the static cutting data. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coefficient which can be determined from the cutting mechanics. The stability analysis is carried out by a two degree of freedom system. The chatter experiments are conducted by exciting the cutting tool with an impact hammer during an orthogonal cutting. A good agreement is shown between the stability limits predicted by theory and the critical width of cut determined by experiments.
A Study on the Pseudoinverse Kinematic Motion Control of 6-Axis Arc Welding Robot
Park, J.S. ; Kim, D.W. ; S.M. Yang ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 170~177
In robotic arc welding, the roll (rotation) of the torch about its direction vector does not have any effect on the welding operation. Thus we could use this redundant degree of greedom for the motion control of the robot manipulator. This paper presents an algorithm for the pseudo- inverse kinematic motion control of the 6-axis robot, which utilizes the above mentioned redunancy. The prototype welding operation and the tool path are also graphically simulated. Since the proposed algorithm requires only the position and normal vector of the weldine as an input data, it is useful for the CAD-based off-line programming of the arc welding robot. In addition, it also has the advantages of the redundant manipulator motion control, like singularity avoidance and collision free motion planning, when compared with the other motion control method based on the direct inverse kinematics.
A study on the surface grinding machining of Engineering ceramics using "In-process dressing" method
J.H. Kang ; S.J. Heo ; Kim, W.I. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 178~189
Engineering ceramics have some excellent properties as the material for the mechanical components. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this paper experiments are carried out to obtain the effect of "In-process dressing" to grind the Engineering ceramics with high efficiency. To save running time for dressing process and obtain restraint effect of diamond grain wear, "In-process dressing" system usint WA stick type honing stone is proposed. Representative High Strength Engineering ceramics A1
are ground with diamond wheel. Also bending strengrh test is carried out to check upward tendancy of mecahnical properties as the result of machining defact restraint through the grinding maching method using "In-process dressing" process. Some results obtained in this study provide useful information to attain the high efficency grinding and the high mechanical properties of Engineering ceramics.rties of Engineering ceramics.
A study on the internal high-speed grinding
S.O. An ; I. Inasaki ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 2, 1993, Pages 190~196
Internal high speed grinding under several high grinding wheel speed condition has been performed in this study for the effects have analyzed and compared with the grinding power, grinding tangential force and accuracy of surface with the carbon tool steel(SK3). The following results have been obtained: (1) Under the workpiece speed constant condition, increasing the grinding speed, the tangential force is decreased, and on the contrary, accuracy of surface is improved. (2) Under the speed ratio (V
) contant condition it is possible to increase the high machining efficiency constraint to tangential grinding force constant.ant.