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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 22, Issue 12 - Dec 2005
Volume 22, Issue 11 - Nov 2005
Volume 22, Issue 10 - Oct 2005
Volume 22, Issue 9 - Sep 2005
Volume 22, Issue 8 - Aug 2005
Volume 22, Issue 7 - Jul 2005
Volume 22, Issue 6 - Jun 2005
Volume 22, Issue 5 - May 2005
Volume 22, Issue 4 - Apr 2005
Volume 22, Issue 3 - Mar 2005
Volume 22, Issue 2 - Feb 2005
Volume 22, Issue 1 - Jan 2005
Selecting the target year
Cone-Beam Microtomography and Its Application
Kim Ho-Kyung ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 7~14
A Study on the PCB(Printed Circuit Board) Drilling by Air Bearing Spindle
Bae Myung-Il ; Kim Sang-Jin ; Kim Ki-Soo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 15~20
This paper describes the PCB drilling using an ultra high-speed air bearing spindle system and micro drill. For this research, we have developed the ultra high-speed air bearing spindle of 125,000 rpm and made an experiment for the application possibility in the PCB drilling. In order to estimate the drilling performance, we have investigated the size and damage of drilled hole, and the wear of drill at 90,000rpm. Results are as follows; we have confirmed the possibility in the PCB drilling of air bearing spindle. In case of micro-drilling PCB at
, the increase in the number of drilling has resulted in a bigger size of holes and also a bigger size of damage. It has been found that the wear of micro drill tends to concentrate in the main cutting edge.
Evaluation of Formability for Warm Forging of The Bevel Gear on The Lubricants and Surface Roughness
Kim Dong-Hwan ; Kim Byung-Min ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 21~28
In the hot forging process lubricant influences on frictional condition only, but in the warm forging process it influence on the formability such as dimensional accuracy, filling state and frictional condition and it is important to estimate a lubricating characteristic of lubricants in the warm forging. In this paper, in order to evaluate the formability of billet in warm forging process according to the lubricant and lubricating method, lubricant and lubricating test have been performed using oil-based and water-based lubricant which were widely used in the hot and warm forging processes. The surface roughness of initial billet was measured to evaluate the influence on the formability of billet and the forming load and dimensional accuracy were compared and evaluated. From the experimental results, it can be known that water-based lubricants are more excellent than oil-based lubricants for warm forging of complex shape like a bevel gear. Also, in this study characteristics of deformation have been investigated according to surface treatment of initial billet.
A Study on the Two-dimensional Formation Control of Free Surface of Magnetic Fluid by Electromagnetic Force
Bae Hyung-Sub ; Yang Taek-Joo ; Lee Yuk-Hyung ; Joo Dong-Woo ; Park Myeong-Kwan ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 29~37
In this study, the control of the free surface deformation of a magnetic fluid for the change in electromagnetic force is discussed. The free surface of magnetic fluid is formed by the balance of surface force, gravity, pressure difference, magnetic normal pressure and magnetic body force. Magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. Thus, the device of a magnetic fluid proposed the complete zero-leakage sealing, oscillator for surface control, boundary layer control, MHD, flow control, flow using magnetic levitation system and surface actuator. This study show the deformation of surface rise due to the intensity of the magnetic field and possibility of two-dimensional control of magnetic fluid through the feedback data of hall sensor.
Design and Implementation of a Bird Type Biped Robot for Entertainment
Kim Dong-Jin ; Yu Seung-Hwan ; Shen Yun-De ; Jang Seung-Ik ; Kee Chang-Doo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 38~45
In this paper, a bird type biped robot for entertainment controlled by R/C servo motors, is built using the embedded RTOS (Real Time Operating System).
V2.00 is used fur RTOS and the board 80C196KC for main CPU. A control algorithm of R/C servo motors is proposed on
preemptive and deterministic property without any extra PWM module. The realized biped robot has 19DOF, that is, 12DOF for both legs, 6DOF for both arms and 1DOF for neck. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.
The Experimental Analysis of Aerodynamic Sound for Fan Motor in a Vacuum Cleaner Using Laser 3-D Scanning Vibrometer and Microphone
Kwac Lee-Ku ; An Jae-Sin ; Kim Jae-Yeol ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 46~51
The vacuum cleaner motor runs at very high speed for suction power. Specially, motor power is provided by the impeller being rotated at very high speed. The centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed of the impeller and small gap distance between the impeller and the diffuser, the level of noise in the centrifugal fan is at BPF(Blade Passage Frequency) and its harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, unsteady flow data are needed. The cause of noise is obtained by dividing the fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, an accelerometer has been used to measure vibration. However, it can not measure vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This study was conducted to perform accurate analysis of vibration and aerodynamic sound for fan motor in a vacuum cleaner using a laser vibration analyzer. A silent fan motor can be designed using the data measured in this study.
Controller Design by Error Shape and Steady-State Error Analysis for a Feed Drive System in CNC Milling Machine
Lee Gun-Bok ; Gil Hyeong-Gyeun ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 52~60
This paper deals with the position control fur a feed drive system in CNC milling machine, which utilizes a modified error signal for the elimination of steady-state error. A linear time-invariant (LTI) system has consistent properties in response to standard test signal inputs. Those also appear in an error curve acquired from the response. From such properties, constructed is an error model for the position control of the feed drive. And then added is the output of the error model to the current error signal. Consequently the resulting proportional control system brings performance improvement in view of the steady-state error. The effectiveness of the proposed scheme is confirmed through simulations and experiments.
Dynamic Model for Compliant Mechanism with Long Flexure Hinges
Choi Kee-Bong ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 61~67
A dynamic model for flexure hinge-based compliant mechanisms is derived. The dynamic model of the previous works do not well describe the behaviors of rigid bodies in the compliant mechanism when the length of the flexure hinge is long. In this study, the effect on the length of the flexure hinge is pointed out and then the dynamic model is derived to overcome the length effect. For verification, modal analyses are carried out using the proposed dynamic model and FEM (Finite Element Method). Finally they are compared by the terms of modal frequency. As the result, the proposed dynamic model can be used in design and analysis of the compliant mechanism.
Construction of a Support System for Determining the Condition of Injection Molding
Yi Il-Lang ; Kim Bo-Hyun ; Baek Jae-Yong ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 68~77
The set-up of an injection molding process is a ye complicated and time-consuming job because it is required to well determine a lot of variables closely related to products. Thus, the productivity of the set-up process mainly depends on operators' expertise and know-how. To solve the problem mentioned before, this research constructs a support system which helps operators determining the condition of the injection molding easily and systematically. The construction of the support system consists of the following four steps: 1) to determine the control variables which affect the target defect types, 2) to design and implement UI(user interface) using a scenario of set-up process, 3) to design and implement the search algorithms for the initial and optima] condition, and 4) to construct the embedded system which integrates the support system with the operating system of a plastic injection molding machine. The test experiments of some typical products are performed using the embedded system to verify the validity of the support system.
Study of Analyzing Roof Panel Using Static Implicit Finite Element Method
Ahn Hyun-Gil ; Jung Dong-Won ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 78~85
The static implicit finite element method is applied effectively to analyze total roof panel stamping processes, which include the forming stage. complicated and abnormal Large size roof panel was analyzed by using commercial program called AutoForm. Analysis results examining possibility and validity of the AutoForm software and the factor study are presented. Further, the simulated results for the total roof panel stamping processes are shown and discussed. Its application is being increased especially in the automotive industrial area for the cost reduction, weight saving, and improvement of strength.
A Study on the Forming Characteristics of Forward and Backward Extrusions
Shim Ji-Hun ; Choi Ho-Joon ; Ok Jeong-Han ; Ham Byoung-Soo ; Hwang Beong-Bok ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 86~92
In this paper a forward-backward can extrusion process are analyzed by using rigid-plastic FEM simulation. FEM simulation is conducted to investigate forming characteristics such as deformation modes fur different process parameters. Design parameters such as thickness ratio, punch angle, friction factor and diameter ratio are selected to study the effect of them on the pattern of material flow. The analysis is focused mainly on the influences of the design factors on deformation pattern in terms of forming load, extruded length ratio and volume ratio. It is known for the simulation that the forming load, the length ratio and the volume ratio increase as the thickness ratio (TR), the wall thickness in forward direction to that in backward direction, decreases. The various punch angles have slight influence on the forming load. length ratio and volume ratio. However friction factor have little effect on the forming characteristics such as the forming load, volume ratio and so on. In addition the forming load increases as diameter ratio (DR), the outer diameter of a can in forward direction to that in backward direction, increases. Furthermore the extruded length ratio is lowest with a certain value of DR=0.85 among diameter ratios. Pressure distribution exerted on the die-material interface is illustrated schematically.
Load Concentration Factor Analysis of Fuel Assembly Guide Thimble
Lee Young-Shin ; Jeon Sang-Youn ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 93~100
The top and bottom nozzles of PWR fuel assembly are connected by guide thimbles and an instrumentation tube that are connected with spacer grids. The fuel rods are inserted into the each cell of spacer grids. The loads acting on the fuel assembly are transmitted to the guide thimbles through the flow plate of top nozzle The axial loads applied to the fuel assembly are not equally distributed among the guide thimble due to the geometry of the top nozzle flow plate and spacer grid. In this study, the load concentration factors for the
fuel assembly were calculated. The analytical model fur the calculation of the load concentration factor of top nozzle flow plate was developed using ANSYS 5.6. The finite element analyses were performed using the model composed of top nozzle, guide thimble, and spacer grid. And, the analysis results were compared with the test results.
Development of Simulation Software for Metering Pump of Synthetic Fibers with Image Processing
Cho Yon-Sang ; Bae Myung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 101~106
It needs to accumulate a store of know-how on the design, precision processing and appraisement for metering pump which is a kind of gear pump fer synthetic fibers. But the period and cost fur development is not effective, because designers experience many trial and error for the pump design and manufacturing process. Therefore, in order to curtail the period and cut down expenses, the analysis and simulation system is required for a designed metering pump. In this study, the pump simulation software was developed with the visual C++ language and the image processing algorithm, and was investigated through a discharge test for the planetary gear type metering pump.
A Study on Filling Holes of the Polygon Model using Implicit Surface Scheme
Yoo Dong-Jin ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 107~114
A new approach which combines implicit surface scheme and point projection method is presented in order to fill the arbitrarily shaped holes in the polygon model. In the method a trimmed surface which has an outer boundary curve is generated by using the implicit surface scheme and normal projection of point onto the base surface. The base surface is constructed by creating smooth implicit surface from the incomplete polygon model through which the surface should pass. In this paper an implicit surface is defined by a radial basis function, a continuous scalar-valued function over the domain
. The base surface is the set of all points at which this scalar function takes on the value zero and is created by placing zero-valued constraints at the vertices of the polygon model. In order to show the validity of the present study, various hole fillings are carried out for the complex polygon model of arbitrary topology.
Elastic Modulus Measurement of a Large Size Digital TV Display Unit
Kim Chang-Hoi ; Moon Seong-In ; Choi Jae-Boons ; Kim Young-Jin ; Lee Jeoung-Gwen ; Koo Ja-Choon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 115~122
As the digital TV markets rapidly growing, many manufacturers introduce large size flat screen TV units. There are two different display types available to large size models which are plasma and TFT-LCD. Since both are constructed with thin large panels that are mostly fragile to even moderate mechanical shock inputs. Some large size panels are severely resonated by the acoustic sound generated TV which deteriorates video quality. Recognizing the potential problems of large displays, accurate measurement of the panels is to be an essential task for the reliable design. Measurement of mechanical properties of a thin large crystallized panel such as TFT-LCD display with traditional material testing equipments is challenging. Since TFT-LCDs are constructed with combination of brittle glass panels, polymer sheets, and liquid crystal, their properties are not only anisotropic but also usually non-linear. Accurate measurement of the properties often requires very expensive facilities. Especially when the size of the test sample is as large as 40-inch or wider, direct measurement cost is prohibitive. Even worse, machining of the large TFT-LCD to make a smaller size specimen that could be fit into a material tester is not possible because of liquid crystal leakage. A new method fer the measurement of elastic modulus of large TFT-LCD panel is presented in this article. The suggested method provides a simple, economic, and user-friendly way fer measuring the elastic modulus of large panels with considerable level of accuracy.
The Effects of an Abnormal Adjusting Intake and Exhaust Valves on the Combustion Characteristics of SI Engine
Park Kyoung-Suk ; Son Sung-Man ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 123~129
The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis fur developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.
A Study on the Nondestructive Evaluation of Material Properties
Kim Hyung-Ick ; Kim Jeong-Pyo ; Seok Chang-Sung ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 130~136
The nondestructive evaluation system consisted of a ball indentation tester and a ultrasonic tester was developed to evaluate material properties. The relations between the parameters from test results using the system and the results of tensile and fracture toughness tests were investigated. The fracture toughness and tensile properties could be determined using the system. Some metallic materials were experimented to predict the fracture toughness and tensile properties and verify the relations between them. The predicted fracture toughness and tensile properties show a good agreement with the results obtained by conventional tests. It is found that the material properties and the material degradation can be evaluated using the nondestructive evaluation system.
Shape Optimal Design to Minimize Stress Concentration in the Journal of the Heating Drum for a Hot-Rolling Press
Kim Won-Jin ; Lee Boo-Youn ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 137~145
The present research deals with structural analysis and optimal design of the heating drum of a hot-rolling press for medium density fiberboard. Stress concentration in the journal of the heating drum is analyzed by the submodel technique of the finite element method. The fatigue life under operating conditions is analyzed and evaluated by the stress-life theory. Shape optimal design problems, to minimize the maximum stress occurring in the journal, are formulated and shape parameters of the corner fillets of the journal are defined as the design variables. The problems are solved by the numerical optimization method and optimal shapes are found. The optimal designs are shown to be reliable in terms of the maximum stress and the fatigue life.
Structural Design Optimization of a High-Precision Grinding Machine for Minimum Compliance and Lightweight Using Genetic Algorithm
Hong Jin-Hyun ; Park Jong-Kweon ; Choi Young-Hyu ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 146~153
In this paper, a multi-step optimization using genetic algorithm with variable penalty function is introduced to the structural design optimization of a grinding machine. The design problem, in this study, is to find out the optimum configuration and dimensions of structural members which minimize the static compliance, the dynamic compliance, and the weight of the machine structure simultaneously under several design constraints such as dimensional constraints, maximum deflection limit, safety criterion, and maximum vibration amplitude limit. The first step is shape optimization, in which the best structural configuration is found by getting rid of structural members that have no contributions to the design objectives from the given initial design configuration. The second and third steps are sizing optimization. The second design step gives a set of good design solutions having higher fitness for lightweight and minimum static compliance. Finally the best solution, which has minimum dynamic compliance and weight, is extracted from the good solution set. The proposed design optimization method was successfully applied to the structural design optimization of a grinding machine. After optimization, both static and dynamic compliances are reduced more than 58.4% compared with the initial design, which was designed empirically by experienced engineers. Moreover the weight of the optimized structure are also slightly reduced than before.
A Numerical Analysis on the Motion of Mechanical Heart Valve(MHV) and Characteristics of Blood Flow in an Elastic Blood Vessel
Bang Jin-Seok ; Choi Choeng-Ryul ; Kim Chang-Nyung ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 154~161
In this study, the leaflet motion of a mechanical heart valve and the characteristics of two-dimensional transient blood flow in an elastic blood vessel have been numerically investigated by using fluid-structure interaction method. Here, blood has been assumed as a Newtonian, incompressible fluid. Pressure profiles have been used as boundary conditions at the ventricle and the aorta. As a result, closing motion of the leaflet is faster than opening one. While opening angles of leaflet grow up, vortex is detected at the sinus and backward of the leaflets. When the leaflet is fully closed, vortex is detected at the ventricle and at that moment maximum displacement of the elastic blood vessel is observed in the vicinity of the sinus region. Maximum displacement is caused in association with the blood flow that is oriented toward the elastic blood vessel.
Development of a Functional External Fixator System for Bone Deformity near Joints in Legs
Lee Ho-Jung ; Chun Keyoung-Jin ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 162~169
The functional external fixator system fur bone deformity near joints in legs using the worm gear was developed for curing the difference angles in fracture bone and the lengthening bar for curing the difference length in fracture bone. Both experiments and FE analysis were performed to compare the elastic stiffness in several loading modes and to improve the functional external fixator system for the bone deformity. The FE model using the compressive and bending FE analysis was applied to the FE analysis due to the angle differences. The results show that the compressive stiffness value in experiment was 175.43N/mm; the bending stiffness value in experiment was 259.74N/mm; compressive stiffness value in FEM was 188.67N/mm; bending stiffness value in FEA was 285.71N/mm. The errors between experiments and FEA were less than 10%. The maximum stress (157MPa) to the angle of clamp was lower than the yield stress (176.4MPa) of SUS316L. The stiffnesses in both axial compressive and bending of the new fixator are about 2 times higher than other products except EBI (2003).
Gait-Event Detection for FES Locomotion
Heo Ji-Un ; Kim Chul-Seung ; Eom Gwang-Moon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 170~178
The purpose of this study is to develop a gait-event detection system, which is necessary for the cycle-to-cycle FES control of locomotion. Proposed gait event detection system consists of a signal measurement part and gait event detection part. The signal measurement was composed of the sensors and the LabVIEW program for the data acquisition and synchronization of the sensor signals. We also used a video camera and a motion capture system to get the reference gait events. Machine learning technique with ANN (artificial neural network) was adopted for automatic detection of gait events. 2 cycles of reference gait events were used as the teacher signals for ANN training and the remnants (
cycles) were used fur the evaluation of the performance in gait-event detection. 14 combinations of sensor signals were used in the training and evaluation of ANN to examine the relationship between the number of sensors and the gait-event detection performance. The best combinations with minimum errors of event-detection time were 1) goniometer, foot-switch and 2) goniometer, foot-switch, accelerometer x(anterior-posterior) component. It is expected that the result of this study will be useful in the design of cycle-to-cycle FES controller.
Three-dimensional Stress Analysis of Implant Systems with Micro Threads in the Maxillary Bone
Shin Ha-Shik ; Han Chong-Hyun ; Lee Soo-Hong ; Chun Heoung-Jae ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 179~186
A comparative study of stress distributions in the maxillary bone with three different types of abutment was conducted. Finite element analysis was adopted to determine stress generated in the bone with the different implant systems with micro threads (Onebody type implant, Internal type implant, and External type implant). It was found that the types of abutments and the number of micro threads have significant influence on the stress distribution in the maxillary bone. They were due to the difference in the load transfer mechanism and the size of contact area between abutment and fixture. Also the maximum effective stress in the maxillary bone was increased with increasing inclination angle of load. It was concluded that the maximum effective stress in the bone was the lowest by the internal implant among the maximum effective stresses by other two types of implants and by appropriate number of micro threads, and that the specific number of micro thread was existed to decrease the maximum effective stress in the maxillary bone due to different implant systems and loading conditions.
Analysis of Temperature Distribution and Residual Stress in Deposition Process of Metal Droplet by Using Laser Beam
Yun Jin-Oh ; Yang Young-Soo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 3, 2005, Pages 187~193
The temperature distribution of the deposited droplet was predicted by using the finite element analysis and it was assumed that the droplet was axisymmetrical model. The analysis of residual stress was performed with the temperature data, which is obtained from the result. Axisymmetric droplet is deposited three times to consider the actual phenomenon of droplet deposition. The analysis of the temperature distribution is respectively performed whenever the axisymmetric droplet is laminated and the residual stresses of the laminated axisymmetric droplet are calculated with the value of the temperature distribution.