Title: Micro-electro discharge drilling characteristics on molybdenum aperture fabrication

Authors: Dave (Dae-Wook) Kim, Xiaolin Chen, Phil Allen

Addresses: School of Engineering and Computer Science, Washington State University, Vancouver, WA 98686, USA. ' School of Engineering and Computer Science, Washington State University, Vancouver, WA 98686, USA. ' The Boeing Co., Seattle, WA 98124, USA

Abstract: In this study, the material removal mechanism for micro-EDM of molybdenum was investigated numerically and experimentally using both single and multiple spark investigations. Single-spark material removal was analysed using a thermo-numerical model which simulated a single spark discharge process and was compared with single-spark experiments. Good correlation between the numerical and experimental data was observed. Multiple-spark material removal was investigated through the creation of apertures using an experimental design in which the input voltage and pulse duration were varied. The material removal rate of molybdenum increases with increasing input voltage and decreasing pulse duration, while the tool wear increases as both input parameters increase. Material removal and debris formation mechanisms are examined as well as the effect of machining parameters on process outputs and aperture quality. A comparably shorter pulse duration is appropriate to produce micro-size molybdenum apertures with a higher removal rate and a lower surface defect such as debris.

Keywords: micro-EDM; molybdenum aperture; numerical modelling; material removal rate; MRR; tool wear; micron-size hole quality; electro-discharge machining; electrical discharge machining; drilling; experimental design; debris formation; aperture quality; surface defects; pulse duration.

DOI: 10.1504/IJMMM.2010.033064

International Journal of Machining and Machinability of Materials, 2010 Vol.7 No.3/4, pp.161 - 175

Published online: 07 May 2010 *

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