• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.258-258
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• 2004

전해 가공은 공작물의 기계적 특성과 무관하게, 빠른 속도로 가공할 수 있는 장점이 있으나, 가공 간극이 비교적 넓어 초정밀 가공에는 널리 적용되지 못했다. 최근 Schuster는 초단 펄스를 이용한 전해 가공으로 가공 간극을 수 $\mu\textrm{m}$ 까지 줄일 수 있고 미세 3차원 구조물의 정밀가공에 초단 펄스를 적용할 수 있음을 보였다. 본 논문에서는 초단 펄스를 이용한 미세 흠의 와이어 전해 가공에 대하여 연구하였다. 전극으로는 지름 10$\mu\textrm{m}$ 백금 와이어를 사용하였으며 공작물은 스테인리스 스틸을 사용하였다.(중략)

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.213-220
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• 2003

By the localization of electro-chemical dissolution region, we succeeded in a few micrometer size hole drilling on stainless steel with the radial machining gap of about 1 ${\mu}{\textrm}{m}$. Tens of nanosecond duration voltage pulses were applied between WC micro-shaft and stainless steel in the 0.1 M $H_2SO_4$ solution. Pt balance electrode was used to drill the high aspect ratio micro-hole without generation of Cr oxide layer on the machined surface. The effects of applied voltage, pulse duration, and pulse period on localization distance were investigated according to machining time. We suggested the taper reduction technique especially brought up on blind-hole machining. High quality micro-holes with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and 12 ${\mu}m$ diameter with 100 ${\mu}m$ depth were drilled on 304 stainless steel foil. The various hole shapes were also produced including stepped holes and taper free holes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.942-945
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• 2001

Pulse electrochemical micromachining offers significant improvements in dimensional accuracy as compared with conventional electrochemical machining. One primary issue in pulse electrochemical micromachining is to identify and control machining depth as well as interelectrode gap size. This paper presents an identification method for the machining depth by in-process analysis of machining current and interelectrode gap size. The inter electrode gap characteristics, including pulse current, effective volumetric electrochemical equivalent and electrolyte conductivity variations, are analysed based on the model and experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.560-563
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• 2004

Invar is a compound metal of Fe-Ni system and contain 36％ Ni. The most distinction characteristic of Invar is the coefficient of thermal expansion is 1.0 10$^{-6}$ /$^{\circ}C$. That is a tenth of general steel material. This low thermal expansion characteristic of Invar is applied to the missile, aircraft, monitor CRT and frontier display's shadow mask such as FED and OLED. The usage of the Invar shadow mask for display is increasing due to the requirement of larger size and flatness monitor. The Invar shadow mask is machined by two ways electro-forming and laser now. However the electro-forming takes a too long time and the laser machining is accompanied with Burr. In this study, PEMM(pulse electrochemical micro machining) is conducted to machine the micro hole to the Invar and 80${\mu}{\textrm}{m}$ hole was machined.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.356-361
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• 2003

Electrochemical micromachining which is not normally considered as a precision process is presented in this paper. The application of voltage Pulses between a tool electrode and a workpiece in an electrochemical environment allows the three-dimensional machining of conducting materials with micrometer precision. In this paper tool-electrodes($5\mu\textrm{m}$ in diameter, 1mm in length) are developed by electrochemical micromaching and micro holes are manufactured using this tool-electrodes we developed already. Micro holes are achieved the accuracy below $50\mu\textrm{m}$ in diameter using ultrashort voltage pulses(0.1-5$\mu\textrm{s}$).

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1052-1058
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• 2003

The possibility of micro/nano machining through electro-chemical process is discussed in this research. Electro-chemical dissolution region is localized within 1 ${\mu}m$ by applying ultra short pulses with tens of nanosecond duration. The effects of voltage, pulse duration, and pulse frequency on the localization distance are investigated. Localization distance can be manipulated by controlling the voltage and pulse duration, and various hole shapes are produced including stepped holes and taper free hole. High quality micro-hole with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and micro-groove with 9 ${\mu}m$ width with 10 ${\mu}m$ depth are machined on 304 stainless steel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.16 no.2
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• pp.7-11
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.491-492
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• 2012

• Journal of the Korean Society for Precision Engineering
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• v.24 no.6
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• pp.105-112
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• 2007

Tungsten wire micro electrochemical machining (W-wire micro ECM) with ultra-short pulses enables precise micro machining of metal. In wire micro ECM, platinum wire has been used because it is electrochemically stable. However, the micro metal wire with low strength is easily deformed by hydrogen bubbles which are generated during the machining. The wire deformation decreases the machining accuracy. To reduce the influence of hydrogen bubbles, in this paper, the use of tungsten wire was investigated. To improve machining accuracy, suitable pulse conditions which affect generation of bubbles were also investigated. The tungsten wire micro ECM can be applied to the fabrication of various shapes. Using this method, various micro-parts and shapes were fabricated.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.308-314
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• 2011

In micro electrochemical machining (micro ECM), machining conditions have been determined to maintain a small side gap and to machine a workpiece stably However, machining speed is slow. To improve machining speed while maintaining the form accuracy, the paper investigates machining parameters such as pulse amplitude, duty ratio, pulse on-time, and the electrolyte's temperature and concentration. The experiment in this study shows that the electrolyte's concentration is the key factor that can reduce machining time while maintaining the form accuracy Micro square columns were fabricated to confirm the machining parameters' effects.