• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.194-201
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• 2004

Optical fibers are indispensable fer optical communication systems that transmit large volumes of data at high speed. But the aligning technology under the sub-micron accuracy is required for the precise axis adjustment and connection. For the purpose of precise alignment of the optical arrays, in this research, we have developed the 12-axis(with 8 automated axis and 4 manual axis) automatic optical fiber alignment system including the image processing-based searching system, the automatic loading system using the robot and the suction toot and the automatic UV bonding system. In order to obtain the sub-micron alignment accuracy, two 4-axis PC-based motion controllers and the two 50nm resolution 6-aixs micro-stage actuated by micro stepping motors are adopted. The fiber aligning procedure consists of two steps. Firstly, the optical wave guide and an input optical array are aligned by the 6-axis input micro-stage with the IR camera. The image processing technique is introduced to reduce primary manual aligning time and result in achieving the 50% decrease of aligning time. Secondly, the IR camera is replaced by the output micro-stage and a wave guide and two optical arrays are aligned simultaneously before the laser power intensity delivered to the optical powermeter reached the threshold value. When the aligning procedure is finished, the wave guide and arrays are W bonded. The automatic loading/unloading system is also introduced and the entire wave guide handing time is reduced significantly compared to the former commercial aligning system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.792-795
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• 2005

The guide-ways of precision machine tools are one of important element of machine tools. It has usually a pair of surfaces for constraint of one direction with bearing. In the case of precision machine tools, non-contact bearing such as hydrostatic bearing and aerostatic bearing is adopted usually. In this case, profiles of rails has effect on straightness and the clearance of bearing has effect on stiffness of guide way, which changes to higher if clearance changes to smaller. The clearance is varied along moving table according to relative distance of pair of rails. The relative distance of pair of rail can be divided by three properties. First and second properties are straightness of each pair of rail and bearing pad. And, third is parallelism about pair of rails and pairs of bearing pad. There are several methods for measuring straightness of each surface such as reversal method, sequential two point method, and way straightness. These straightness measuring methods are always acquiring deviation of profile from eliminating linear fitted inclined line and don't have the information of parallelism. Therefore, to get the small clearance for high stiffness, the straightness of rail and bearing pad and parallelism about pair of rails and pair of bearing pads are measured for correction such as regrinding, reassembling and lapping. In this research, new and easy method for measuring parallelism of pair of rails is suggested. Two displacement probe and sensor stage, which is carry on the displacement sensor, are needed. The simulation and experiment was accomplished about pair of horizontal guide way to confirm the measurement of parallelism. And, the third probe is added to measure the straightness of each rails by sequential two point method. From the estimation of combined these two methods, it is confirmed that the profiles of a pairs of rails can be measured.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1980-1983
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• 2005

The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excellent price and strength. The sheet metal process with above characteristic is common used in industrial field, but in order to analysis irregular field problems the reliable and economical analysis method is demanded. Finite element method is very effective method to simulate the forming processes with good prediction of the deformation behaviour. Among Finite element method, The static-implicit finite element method is applied effectively to analyze real-size auto-body panel stamping processes, which include the forming stage. In this paper, it was focussed on the drawability factors on auto-body panel stamping by AUTOFORM with using tool planing alloy to reduce law price as well as high precision from Design Optimization of ide. According to this study, the results of simulation will give engineers good information to access the Design Optimization of die.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.118-124
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• 2006

The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excel lent price and strength. The sheet metal process with above characteristic is common used in industrial field, but in order to analysis irregular field problems the reliable and economical analysis method is demanded. Finite element method is very effective method to simulate the forming processes with good prediction of the deformation behavior. Among Finite element method, the static-implicit finite element method is applied effectively to analyze real-size auto-body panel stamping processes, which include the forming stage. In this paper, it was focused on the drawing ability factors on auto-body panel stamping by AUTOFORM with using tool planning alloy to reduce law price as well as high precision front Design Optimization of die. According to this study, the results of simulation will give engineers good information to access the Design Optimization of die.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.150-156
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• 1994

To meet the process requirement of semiconductor device manufacturing, it is necessary to improve the alignment accuracy in exposure equipments. We developed the excimer laser stepper and will describe the methodology for alignment measurement and experimental results. Our wafer alignment system consists of off-axis optics, TTL(Through The Lens) optics and high precision stage. Off-axis alignment utilizes the image processing and /or diffraction from thealign marks of off-centered chip area. On the other hand, TTL alignment can be used for the die-by-die alignment using dual beam interferometry. When only off-axis alignment was used, the experimental alignment error(lml+3 .sigma. ) was 0.26-0.29 .mu. m, and will be reduced down to 0.15 .mu. m by adding TTL alignment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.183-193
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• 2003

Micro-weighing device by using null balance method is being essential part in fields of high-technology industries such as precision semiconductor industry, precision chemistry, biotechnology and genetics etc. Also, requirements for high resolution and for large measurement range increase more and more. The performance of the micro-weighing device can be determined by the mechanism design and analysis. The analytical design method has been proposed for the performance improvement such as resolution, measurement range and fast response. The 2-stage displacement amplification is designed to overcome the limit of conventional force transmitting lever. The parallel spring is designed for the measurement result independent of the input force position variation. Also, the natural frequency of mechanism is analyzed for the fast response. After each analysis, optimal design has been carried out. To verify the analysis and design result, characteristics experiments had been carried out after construction. Finally, the system had been controlled.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.2
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• pp.84-93
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• 1996

Non-destructive inspection techniques using laser have been broading their application areas as well as growing their measurement skills together with the rapid development of circumferential technology like fiber optics, computer and image processing. The ESPI technique is already on the stage of on-line testing with commercial products in developed country nations. Especially, this technique is expected to be applied to the nuclear industry, automobile and aerospace because it is proper for the vibration measurement and it can be applied to objects of a high temperature. This paper describes the use of the ESPI system for measuring vibration patterns on the reflecting objects. Using this system, high-quality Jo fringes for identifying mode shapes are displayed. A bias vibration is introduced into the reference beam to shift the Jo fringes so that fringe shift algorithms can be used to determine vibration amplitude. Using this method, amplitude fields for vibrating objects were obtained directly from the time-average interferograms recorded by the ESPI system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.930-933
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• 2005

Non-destructive inspection techniques using laser have been breading their application areas as well as growing their measurement skills together with the rapid development of circumferential technology like fiber optics. computer and image processing The ESPI technique is already on the stage of on-line testing with commercial products in developed country nations. Especially, this technique is expected to be applied to the nuclear industry, automobile and aerospace because it is proper for the vibration measurement and it can be applied to objects of a high temperature. This paper describes the use of the ESPI system for measuring vibration patterns on the reflecting objects. Using this system, high-quality Jo fringes for identifying mode shapes are displayed. A bias vibration is introduced into the reference beam to shift the Jo fringes so that fringe shift algorithms can be used to determine vibration amplitude. Using this method. amplitude fields for vibrating objects were obtained directly from the time-average interferometer recorded by the ESPI system.

• 대한공업교육학회지
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• v.42 no.1
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• pp.1-29
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• 2017

The purpose of this study was to investigate the vocational identity through the reflection of the major experience as the teacher through the life history of the technical high school. In order to achieve the purpose of this study, two technical high school mechanical and career teachers were selected as research participants and in-depth interviews were conducted with them. The data obtained through the in-depth interviews were analyzed through six steps. Six major experiences of the participants were identified as results of the research: (1) the experience of trying to train the specialist of precision machining in the beginning of teacher's life, (2) experience as a skill competition team teacher, (3) experience of innovating public education by introducing new industry field, (4) experience of constant learning new field and sharing with colleagues, (5) experience in the rapid change of the status of technical high school, (6) experience in the prevention of students' safety accidents and maintenance of the practice field. Through these educational experiences, each research participant was forming one's vocational identity as a mechanical teacher. The vocational identity of the research participants were identified as follows: (1) identity drifting phase, (2) identity stability stage, (3) transition stage of the teacher role, (4) suspended stage to preserve identity, (5) identification sublimation stage, (6) identification of the true meaning of the teacher, and integration of the identity. Through these six steps, their identities were formed, strengthened and changed at each stage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.10
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• pp.1648-1655
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• 1997

The intake noise, a major source of vehicle noises, has rapidly become a noticeable, and has been studied to reduce the level. Traditionally, the intake system has been developed through a experiment, namely, the trial and error process. This approach requires very high cost and long time consuming to develop the system. Recently, FEM and BEM are becoming useful in analysis of the intake system, and te results of analysis are very valid. But because these techniques also require high cost and long analysis time, these are generally not practical tool at the early stage of the development of an intake system. In this study, the software was developed to predict and analyze the acoustic characteristics of an intake system. It was based on the Transfer Matrix Method and operated to analyze a simplified intake system in a personal computer. It can be used early in the design stage of development of the intake system. This study presented an improvement to reduce the level of an intake noise. It was to select the optimum position of a resonator and verified by NIT/SYSNOISE, FE analysis commercial software, and testing a prototype.