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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
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
동시공학 설계 생산 시스템
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 5~20
지능형 생산시스템과 CAM의 지능화
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 21~24
Some issues in Computer Aided Process Planning for integration of manufacturing information
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 25~30
Characteristics of Ferrite-Resin Material for Improving Vibration-proof Property
Park, Y.I. ; Maeng, H.Y. ; Won, S.T. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 31~40
The vibration-proof material normally used in structural components of precision machinery or measuring instruments requires higher damping in vibration and better characteristics in dimensional stability and rigidity to accomplish the quality assurance of the products. In this study the ferrite-resin material, which is the mixture of epoxy resin and the oxidized steel (Fe
: ferrite) in consideration of characteristics of aggregator and binder, is developed and investigated as one of vibration-proof materials. Four kinds of composite plates for experiments are made by adding another filler materials such as steel powder, granite powder and carbon-fiber sheet to the basic ferrite-resin matrix. Their characteristics are compared with a cast iron specimen which has the same bending rigidity as other specimens. The ferrite-resin material gives the best damping effect in the motor-induced vibration test. Therefore, the material can be applied to the manufacturing industry for vibration damping of machine elements.
Transitional Vibration Characteristics of Single Degree of Freedom System through the Resonance
T.H. Chung ; D.P. Hong ; S.H. Tae ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 41~46
The transitional characterisics of oscillations and rotational speeds from the starting to the stationary states in damped single degree of freedom systems acted upon the rotor unbalance forces are studied. Angular travel is assumed to vary with time. The theoretical analysis is obtained by using Laplace transform method. Integration involved in the theoretical results is carried out by the numerical analysis program of continuous-time linear systems to arbitrary inputs. It is evident that the transitional charcterixtics of a machine are affected remarkably by damping ratios, stationary angular velocity time and frequency ratios.
A Study on Plastic Strain in Machined Surface
Kim, T.Y. ; Y.Y. So ; H.G. Shin ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 47~56
Typical plastic strains in the machined surface are very difficult to measure, since they are located within a very short distance from the surface and they change very rapidly. There is an alternative way to determine the residual strain in plastically deformed materials by measuring the grain size after a subsequent recrystallization precess. Although, this technique has been successfully applied by several researchers to find the plastic zone around notches and cracks in various materials and welding beads, few works have been reported using the recrystallization method to determine the residual strains in machined surface. Therefore, the purpose of this investigation is to explore the effectiveness of the recrystallization technique in machining applications and in particular, to find the effect of cutting parameters, i.e., depth of cut, rake angle, on the plastic strains. As the result, the recrystallization technique was succesfully applid to determine the plastic strain in machined surface.
A Study on Coating Deviation Effect by Air Knife Characteristics in CGL
Bae, Y.H. ; Ahn, D.S. ; Lee, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 57~68
Air Wiping technique is widely used because of easy and efficient coating control in present CGL. Coaring weight is decided by nozzle header pressure, strip line speed and distance between strip and nozzle. Coating defects are results from unbalance of these factors and coating equipment calibration inaccuracy. Therefore, this study is mainly dealing with the cause of coating defects such as edge overcoating and coating deviation. The coptimum working condition is suggested by formulated coating model using collected working data. We developed two demension analysis program for air flow in nozzle and calculated dynamic pressure and air velocity with this program. The productivity and coating guality are improved by applying the result of this reserach.
Work Roll Diagnosis by Roll Life Prediction Model in Hot Rolling Process
Y.H. Bwe ; S.K. Jang ; Lee, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 69~80
It is important to prevent roll failure in hot rolling process for reducing maintenance coat and production loss. Roll material and rolling conditions such as the roll force and torque have been intensively investigated to overcome the roll failures. In this study, a computer roll life prediction system under working condition is developed and evaluated on IBM-PC level. The system is composed and fatigue estimation models which are stress analysis, crack propagation, wear and fatigue estimation. Roll damage can be predicted by calculating the stress anplification, crack depth propagation and fatigue level in the roll using this computer model. The developed system is applied to a work roll in actual hot rolling process for reliability evaluation. Roll failures can be diagnosed and the propriety of current working condition can be determined through roll life prediction simulation.
Tool Wear Monitoring with Vision System by Block Processing
Lee, S.J. ; C.Y. Cho ; Lee, J.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 81~86
It is well known that the interest on the on-line sensing of tool wear is growing more and more with the aim of controlling machine tools productivity from the point of view of quality. This paper describes the sensing of the amount of flank wear with vision system. To obtain a proper image He-Ne laser generator is used as the lighting source and obtained image is processed with block processing algorithm and morphological image processing method. By means of this system it is possible to evaluate the parameters of tool wear. Experimental tests performed with this system on an NC lathe have shown good performances here described and discussed.
A Study on the Optimal Shape Design Using Automatic Regridding and Design Element
Kim, H.R. ; B.J. Dan ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 87~96
In this study, the peak stress of a fuillet in elastic structure was optimized to have minimum value by using quadratic isoparametric element. The method of auomatic gridding was also developed along with shape algorithm and design element technique was adopted in selecting design variables. The computer program developed was combined with the Hooke-Jeeves direct algorithm of optimization techniques in order to minimize the peak stress of the fillet. The imployment of design element technique significantly cut down computer time by the reduction in design variables, and the opitmum fillet shape with uniform minimum stress was obtained by varying design variables along x and y directions in improving the shape compared to other results. By using automatic gridding, in which Bezier surfaces and Coons surfaces of cubic interpolation were employed, the irregular boundary was removed resulting in smoother anbd more accurate fillet shape possessing uniform minimum stress.
Study on Fracture Life Under Mutual Interaction of Creep and Fatigue
Y.E. Cho ; Kim, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 97~106
This is the study on fracture life under the interaction of creep and fatigue. It is difficult to explain the interaction of the creep and fatigue with indication of frequency but the dependency of the time should be considered. The formulation of material varieties causing by interaction of creep and fatigue is required in the accumulative damage method. The strain range partition method requires some of modification corresponding to the changes in temperature and load. All of other method also comprehended with above mentioned problems. Generally, in this field, the variety of stress-strain and suitable parameter is required and connective study between the macro and micro results seems to be insufficient. The linear damage rule is acquiring the support generally but it requires modification in the hgigh temperature instruments. The variety of stress effecting on crack and variety of stress on the metallurgical side are considered to be problems in the future days.
A Study on the Dynamic Analysis for Flexible Robotic Arms
Kim, C.B. ; Y.S. You ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 107~116
In the design and operation of robitic arm with flexible links, the equation of motion are required to exactly model the interaction between rigid body motion and elastic motion and to be formulated efficientlyl. In this paper, the flexible link is represented by applying the D-H rigid link representation method to measure the elestic deformation. And the equations of motion of robotic arm, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated from the principle of virtual power. Dynamic characteristics due to elastic deformation of each link are obtained by using F. E. M to model complex shaped link acurately and by eliminating elastic modes of higher order that do not largely affect motion to reduce the number of elastic degrees of freedom. Also presented is the result of simulation of flexible robotic arms whose joints are controlled by direct or PD control.
A Study on the Analysis of Magnetic Field in Magnetic Deflection Yoke Based on the Oblate Spheroidal coordinates
J.D. Seo ; H.S. Yoo ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 117~124
This paper presents the study on the magnetic field analysis of magnetid deflection yoke using integral equation method. An integral equation method is developed for the computer modeling of the magnetic fields produced by color CRT and T.V. deflection yoke. Deflection of electron beams using magnetic fields is applied in a variety of display instruments such as te.evision receivers, electron probe instruments, etc. The magnetic field is solved by dividing these into the finite elements in the whole domain : the saddle coil which deflects the electron heam horizontally, the toroidal coil which deflects it vertically, magnetic core which enhances the magnetid fields genterated by the both coils. Using oblate spheroidal coordinates, this paper has had an easier access to the shape of magnetic deflection yoke chasing the boundaries than other coordinates.
A Study on the Taper Plunger Type Proportional Electromagnet for ISC Valve
C.S. Song ; Lee, T.H. ; J.S. Yun ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 125~132
On this study, magnetic force versus input currents is analyzed by modeling taper plunger type proportional electromagnet of ISC valve using the permernce method. And, the reliabiliy of simulation is verified by comparing the experimental values with the calaulate magnetic force. From the result of this study, it is found that the taper angles at plunger and core, the length of air gap between plunger and yoke are the prumary factors in designing taper plunget type proportional electromagnet. Magnetic force is decreased as a whole according to increasing the air gap between pluger and yoke, and vise versa. But, the magnetic force is not proportional to current, when the air gap is very small. In case of decreasing the taper angle of pluger, the stroke range of plunger where magnetic force is proportional to current becomes farther from core.
Inverse Dynamic Analysis of A Flexible Robot Arm with Multiple Joints by Using the Optimal Control Method
Kim, C.B. ; Lee, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 133~140
In this paper, we prpose a method for tracking optimally a spatial trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint euqations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation result of a flexible planar manipulator is presented.
A Study on Estimation of a Mobile Robot's Position Using Neural Network
Kim, J.H. ; Lee, J.C. ; H.S. Cho ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 141~151
For navigation of a mobile robot, it is one of the essential tasks to find out its current position. Dead reckonining is the most frequently used method to estimate its position. Hpwever conventional dead reckoner is prone to give us false information on the robot position especially when the wheels are slipping. This paper proposes an improved dead reckoning scheme using neural networks. The network detects the instance of wheel slopping and estimates the linear velocity of the wheel; thus it calculates current position and heading angle of a mobile robot. The structure and variables of the nerual network are chosen in consideration of slip motion characteristics. A series of experiments are performed to train the networks and to investigate the performance of the improved dead reckoning system.
Experimental Investigation of the Dynamic Fracture Toughness for Aluminum Alumina Whisker Metal Matrix Composites
Kim, M.S. ; Lee, H.C. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 152~160
This paper presents experimental study of the static and dynamic fracture toughness behavior of a A1-6061 aluminum alloy reinforced alumina( .delta. -A1
) whiskers with 5%, 10%, 15% volume fraction. The static fracture tests using three-point bending specimen were performed by UTM25T. And drop weight impact tester performing dynamic fracture tests was used to measure dynamic locads applied to a fatigue-precracked specimes. The oneset of crack initiation was detected uwing a strain gage bonded near a crack tip. The value of static fracture toughness
and dynamic fracture toughness
were decided on the basis of linear elastic fracture mechanics. The effects of fiber volume fraction and loading on fracture toughness were investigated. The distribution of whiskers, bonding state and fracture interfaces involved in void, fiber pull-out state were investigated by optical microscopy(OM) and scanning electron microscopy(SEM)
Tool Path Generation of a Die Cavity Defined by Sculptured Surfaces
Y.T. Jun ; Park, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 161~167
This paper deals with a new method for the machining of a die cavity defined by sculptured surfaces. In machining die cavities or pockets, process planners have been faced with some troulbes. One of the troubles ius to rebove a great deal of material within a given boundary while avoiding cutter interference. Cutter interference is a ciritical problem in NC machining of a die cavity. Even though this cavity machining has been implemented in many CAM systems, most of them can handle limited shapes of cavities or pockets. In this paper, a procedure has been developed to machine die cavity or pocket of a sculptured surface. The offset surfaces of the part surfaces and boundary surfaces are determined to calculate the intersection curves. These intersection curves form a FACE on the part surface, and the interference free tool pathe is generated by eliminating the points outside the FACE when computing the cutter contact (CC) data. Additionally, the cutter location (CL) data obtained from the CC data convert to an NC data. The NC data generated through this algorithm are verified on the CINCINNATI milling machine. A propotype die cavity machining system has been implemented in FORTRAN language and FIGARO graphics library on IRIS workstation.
A study on the measurement of flank wear by computer vision in turning
Kim, Y.I. ; B.H. Ryu ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 168~174
A new digital image processing method for measuring of the flank wear of cutting tool is presented. The method is based on computer vision technology in which the tool is illuminated by two halogen lamps and the wear zone is visualized using a CCD camera. The image is converted into digital pixel and processed to detect the wearland width. As a conclusion, it has been proved that the average wearland area and mzximum peak values of the flank wear width can monitored effectively to a measuring resolution of 0.01mm.
Learning Assembly Strategies for Chamferless Parts
D.S. Ahn ; Kim, S.Y. ; H.S. Cho ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 175~181
In this paper, a practical method to generate task strategies applicable to chamferless and high-precision assembly, is proposed. The difficulties in devising reliable assembly strategies result from various forms of uncertainty such as imperfect knowledge on the parts being assembled and functional limitations of the assembly devices. In approach to cope with these problems, the robot is provided with the capability of learning the corrective motion in response to the force signal trrough iterative task execution. The strategy is realized by adopting a learning algorithm and represented in a binary tree type database. To verify the effectiveness of the proposed algorithm, a series of simulations and experiments are carried out under assimilated real production environments. The results show that the sensory signal-to-robot action mapping can be acquired effectively and, consequently, the chamferless assembly can be performed successfully.
Sizing of lnner Flaw in Resin by using Ultrasonic spectroscopy
Han, E.K. ; Kim, Y.J. ; Park, I.G. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 182~190
In manufacturing process of semiconductor package, the thermal stress owing to high temperature in moulding and the bubbles generated in chip bonding process become main causes to produce void. On this study we evaluated quantitatively void size by use of ultrasonic spectroscopy method which analyze the reflective pulses with broad band frequency in frequency domain, and after destructive testing we verified effectiv- eness of sizing void by use of ultasonic spectroscopy.
Evaluation of Precision Cutting Performance by Bending Vibration Made Shapes of Main Spindle
Park, B.Y. ; J.G. Kom ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 191~197
In this paper, experimental studies are mainly carried out for the evaluation of precision cutting performance of a machine tool spincle running at high speed with the low load, in consideration of the bending vibration characteristics. As a result a process in presented for the practical application in the machine tools industry to evaluate the cutting performance in design stage of spindles.
Finite Element Analysis Design of Axisymmetric Deep Drawing Process by Local Heating
D.S. Woo ; I.S. Song ; D.Y. Yang ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 198~204
The study is concerned with finite element analysis and design of axisymmetric deep drawing by local heating. When the bottom shape of a cup is not flat but in complex-shaped, i.e., hemispherical, the cup cannot be drawn in one or two processes in the conventional deep drawing process and the limit drawing ratio is limited as well. By introducing local heating selectively with regards to the heating position, the formability of the sheet metal can be greatly increased with the reduced number of processes. In the Process analysisthe rigid- viscoplastic finite element method is employed and the temperature effect is incorporated. Bishop's step-wise decoupled method is employed to analyze the thermomechanical interaction between deformation and heat transfer. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed for various combinations of heat application in the punch and the die. At the first stage of deep drawing stretch forming is practically carried out by firmly pressing the blankholder with the punch and the die heated at various levels of temperature. Then at the second stage the same cup is drawn for the saame or different combination of temperature. From the computation, it has thus been shown that the fromability of a cup is greatly increased in two-stage deep drawing with increased limet drawing ratio.
Development of Computer Modules for Precision Measurement of Geometric Tolerances
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 205~219
Digital Image Processing Technique for Photoelastic Isochromatic Fringe Sharpening
T.H. Baek ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 220~230
Photoelastic isochromatic fringes related to the difference of principal stresses have some bandwidth whose light intensities are not constant and asymmetrical in experimental images. Hence, it is difficult to measure fringe order accurately at a data point by visual observation. In this study, a method of fringe sharpening, which can extract shapened lines from both full-and half-order fringes by digital image processing, is developed. To test the method, various simple photelastic fringe patterns are simulated and their images are processed to yield sharpened lines. The method is then applied to general problems such as images of a circular disk compressed by diametrically concentrated loads and a circular cylinder sybject to internal pressure. The procedure is proved to be capable of extracting sharpened lines accurately from photoelastic isochromatic fringes.
Laminated Injection Mold by the Brazing of Laser Cut Sheets
Y.M. Cho ; Kim, J.D. ;
Journal of the Korean Society for Precision Engineering, volume 10, issue 3, 1993, Pages 231~238
Mold-marking industries currently demands to reduce the tooling costs and time in mold making and to improve the productivity and quality in injection molding process. These problems can be easily solved by the laminated injection mold which is made by laser cutting metal sheets and bonding them by the brazing. Comparing with the conventional mold making technology which mainly depends on the machining, the new thchnology enables an arvitary design of cooling circuit whithout any restrictions of geometry. Therefore, it will offer high production tata of the injection molding processes. This paper evaluates the conventional and laminated injection mold making processes with a simple molding geometry, and also the cooling efficienty of the kinds of mold with the filling and cooling analyses. The results show that the laminated injection mold process takes much shorter time in tooling and cooling, and distributes temperatures more uniformly than the conventional one.