• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.27-28
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.13-14
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.21-22
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• 2011

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.444-444
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• 2010

최근 복잡한 고진공 시스템에서 수행되는 플라즈마 공정을 대신하여 진공 시스템 없이 대기압 플라즈마를 이용한 보다 경제적이고 신속하게 공정을 수행하는 연구가 활발히 진행 중이다. 이러한 대기압 플라즈마의 높은 응용성을 이용한 에칭과 증착 등의 기술은 플라즈마의 물리적 접근 없이 세계적으로 몇몇 선도 연구그룹에서 시도되고 있다. 본 연구팀에서는 대기 중에서 He, Ar, $N_2$, $O_2$, Air 등의 여러 종류의 기체에서 방전하여 미세가공이 가능한 $500\;{\mu}m$ 이하의 마이크로 제트를 개발하였다. 입력전압, 기체유량, 노즐의 구조와 크기 등의 여러 운전변수의 조절을 통해 폴리머 기판위에서 방전되는 마이크로 플라즈마 제트의 안정된 방전조건을 찾았고, 전압-전류 특성곡선(V-I characteristics), 광방출분광법(OES), 시간분해 이미지 촬영법(ICCD), 기체온도 측정법 등을 이용하여 발생된 플라즈마의 물리적인 특성을 분석하였다. 발생된 플라즈마를 이용해 처리된 폴리머 기판의 물성변화를 AFM을 통해 관찰하여 짧은 플라즈마 처리시간에도 효과적인 표면개질의 변화를 확인하였다. 마지막으로 본 기술을 이용한 대기압 마이크로 공정의 응용기술 및 가능성을 연구하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1075-1079
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• 1995

It is difficult to machine microparts, such as microshaft and microholes, by conventional machining. Such micropart can be easily machined by EDM because it's machining force is very low. In micro-EDM, the precise electrode movement and discharge energy control are important. Therefore, high precision motion stage and EDM device with high performance is necessary. In this research, a new EDM machine was developed and microshaft and microhole, with various shape and size, was machined.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.877-878
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.105-106
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.509-510
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• 2006

Simulation of micro electrical discharge machining (micro-EDM) process using finite element analysis is proposed. Multiphysics model which has three steps; heat transfer analysis, structural analysis and electric field analysis is developed for simulation. Machined surface for successive five discharges is simulated using developed multiphysics model. Machined surface roughness was simulated under two discharge conditions and the simulated results are compared with actual machined surfaces. From the comparison it is demonstrated that the model can accurately predict the machined surface with the error less than $0.5{\mu}m$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.422-425
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• 2005

This study predicts the heat-affected zone (HAZ) after electrical discharge machining. To predict HAZ, the temperature distribution is calculated using FEM. Heat flux is calculated from electrical energy, and it can be assumed Gaussian distribution. Plasma channel expands as time goes. Copper and NAK80 are used as the workpiece material. The depth of HAZ in simulation is determined by temperature distribution. The simulation results were compared with a developed actual single discharge crater. Through investigating the cross section of simulated & actual craters, the depth of HAZ in simulation and experiment are compared. Simulation model can predict the crater shape.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.366-369
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• 2005

Electrochemical discharge machining (ECDM) has been found to be potential fur the micro-machining of non-conductive materials such as ceramics or glass. However this machining process has its own inherent problem that the reproducibility is too low to get the available geometric accuracy fur micromachining applications. One main challenge in reaching this goal is the control of the hydrogen built around the tool-electrode in which happen the discharges. This paper proposes the methods to improve the geometric accuracy using powder-mixed ECDM process. The experimental results show the effects of powder producing improved geometric accuracy by averaging and decreasing the concentration of spark energy.