• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.11a
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• pp.79-87
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• 2002

An attempt to automate the surface finishing process of the die and mould has been carried out. An UMB(Ultrasonic Micro Burnishing) equipment which brought the micro plastic cold deformation to the 3D sculptured surface of mold and dies by ultrasonic vibration and static load, was developed and installed at the head stock of a vertical machining center. To be satisfied with the required surface roughness and hardness, the DB based program was also developed and applied. This equipment composes of UMB equipement, CNC vertical machining center, CAD/CAM system and the DB based program fer optimal condition. UMB processing effect was obtained from initial value Ral.25 and Hk337 to Ra0.085 and Hk521 and similar result was shown in industrial mould application.

• Design & Manufacturing
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• v.2 no.1
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• pp.27-31
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• 2008

The object of this study is a manufacture of buff die using CAM systems. Systems are consist of AutoCAD, CAM software and CNC milling machine. CAM software is purpose of G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for networking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.561-562
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• 2006

To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the grinding surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.813-817
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• 2012

Laser assisted machining (LAM) is machining method that performs a machining for workpieces using laser beam preheating. LAM is in the early stage of its applications and has only been used in limited fields including turning, planning and micro end-milling throughout the world. LAM system should be able to move to the laser radiation direction and to rotate on a tool path for machining of complex shapes. A laser module with two-axis manipulator is designed in this study. It has been performed static structural analysis and shape modification of the manipulator. As the results of shape modification it has been obtained better results than the initial model. These results will be able to use in development of the two-axis manipulator.

• Journal of Welding and Joining
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• v.28 no.4
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• pp.61-66
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• 2010

Silicon nitride is widely used as an engineering ceramics because it has high strength, abrasion resistance and corrosion resistance even at high temperature. However, machining of silicon nitride is difficult due to its high hardness and brittleness. Laser assisted machining(LAM) allows effective cutting using CBN tool by locally heating the cutting part to the softening temperature of YSiAlON using the laser beam. The effect of preheating depending on process parameters were studied to find out the oxidation mechanism. If silicon nitride is sufficiently preheated, the surface is oxidized and $N_2$ gas is formed and escapes from the material, thereby making the cutting process more advantageous. During laser preheating process before machining, high temperature results in strong oxidation which makes the bloating, silicate layers and micro cracks. Using the results of these experiments, preheating characteristics and oxidation behavior were found out.

• Journal of Welding and Joining
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• v.28 no.5
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• pp.80-85
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• 2010

This study focused on laser assisted machining (LAM) of silicon nitride ceramic that efficiently removes the material through machining of the softened zone by local heating. The effects of laser-assisted machining parameters were studied for cost reduction, and active application in processing of silicon nitride ceramics in this study. Laser assisted machining of silicon nitride allows effective cutting using CBN tool by local heating of the cutting part to the softening temperature of YSiAlON using by the laser beam. When silicon nitride is sufficiently preheated, the surface is oxidized and decomposed and then forms bloating, micro crack and silicate layer, thereby making the cutting process more advantageous. HIPSN and SSN specimens were used to study the machining characteristics. Higher laser power makes severer oxidation and decomposition of both materials. Therefore, HIPSN and SSN specimens were machined more effectively at higher power.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.50-58
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• 2009

Micro laser fabrication techniques can potentially be used for the manufacture of microstructures on the thin flat surfaces with large diameter that are frequently used in semiconductor industries. However, the large size of wafers can cause the degraded machining accuracy of the surface because it can be tilted or distorted by geometric errors of machines or the holding fixtures, etc. To overcome these errors the off-line focusing error compensation method is proposed. By using confocal autofocus system, the focusing error profile of machined surface is measured along the pre-determined path and can be compensated at the next machining process by making the corrected motion trajectories. The experimental results for silicon wafers and invar flat surfaces show that the proposed method can compensate the focusing error within the level of below $6.9{\mu}m$ that is the depth of focus required for the laser micromachining process.

• 전기의세계
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• v.42 no.5
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• pp.23-33
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• 1993

마이크로 머신이란 글자 그대로 기계의 크기가 몹시 작은 기계를 의미한다. 기계전체의 크기가 1mm정도 혹은 그 이하인 기계를 마이크로 머신이라 일컫는데 이러한 기계들은 주로 아주 작고 가변운 물체(예를 들면 미생물체, 세포등)를 조작하거나, 아주 작은 물리량(예를 들면 변위, 힘, 각도, 유량등)을 발생시키거나 측정하는데 유리하다. 마이크로 머신으로의 초대(I) (전기학회잡지 1992년 11월호 기술해설 참조)에서는 마이크로 머신(MEMS, Micro Eletro Mechanical System)의 대표적인 연구성과를 소개하고, 주요한 제작기술인 Surface micro machining과 MEMS에 관련한 주요학술대회중의 하나인 IEEE Workshop을 소개하고, 1993년도 IEEE MEMS Workshop에서 발표된 연구를 중심으로 최근의 연구현황을 살펴보기로 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.629-630
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• 2008

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.53-60
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• 1998

In this study, it is experimented to find factors effecting surface roughness using the system of experiments. in the mirror surface finishing system. (1) The film feed and oscillation frequency in $40{\mu}m$ abrasive film, grinding speed in $30{\mu}m$, and machining time in $15{\mu}m$15 are the main factors effecting the surface roughness. (2) Applying the optimal finishing condition to $40{\mu}m$, $30{\mu}m$, $15{\mu}m$ abrasive finishing film in sequence, it is possible to obtian about Ra 10 nm surface roughness on SM45C workpiece. (3) Application of the system of experments to the micro abrasive grain film finishing was very effective method in the extraction of main factor and optimal condition.