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1754658 
Journal Article 
Surface quality improvement of wire-EDM using a fine-finish power supply 
Yan, MuT; Lai, YiP 
2007 
Yes 
International Journal of Machine Tools and Manufacture
ISSN: 0890-6955 
47 
11 
1686-1694 
WOS:000248673000005 
This paper presents the development and application of a new
fine-finish power supply in wire-EDM. The transistor-con trolled power supply composed of a
full-bridge circuit, two snubber circuits and a pulse control circuit was designed to provide the
functions of anti-electrolysis, high frequency and very-low-energy pulse control. Test results
indicated that the pulse duration of discharge current can be shortened through the adjustment of
capacitance in parallel with the sparking gap. High value of capacitance contributes to longer
discharge duration. A high current-limiting resistance results in the decrease of discharge
current. Peak current increases with the increase of pulse on-time and thus contributes to an
increase in thickness of recast layer. Experimental results not only verify the usefulness of the
developed fine-finish power supply in eliminating titanium's bluing and rusting effect and
reducing micro-cracking in tungsten carbide caused by electrolysis and oxidation, but also
demonstrate that the developed system can achieve a fine surface finish as low as 0.22 mu m R-a.
(C) 2007 Elsevier Ltd. All rights reserved. 
wire-EDM; anti-electrolysis; fine-finish power supply; surface roughness