Study of Micro Vibration Aided Self-Acting Gas Film Electrochemical Discharge Drilling
Date Issued
2009
Date
2009
Author(s)
Huang, Chian-Hsing
Abstract
Electrochemical discharge machining (ECDM) is widely used to machine the non-conductive brittle materials such as glasses and ceramics. However a lot of significant problems are still remained unsolved, eg., the machining depth, the machining rate, the enlarging hole condition and the tapering hole phenomenon etc. Self-acting gas film electrochemical discharge drilling process injected air through a hollow tube electrode during the drilling process to reduce the enlarging and tapering hole phenomenon. But the experimental results showed that the surface roughness of the workpiece was worse comparing to that machined without the air injecting process because the local thickness of the gas film around the electrode became unstable and there was only few sparks taking place non-uniformly around the tube electrode. Hence, the purpose of this study is to improve the self-acting gas film electrochemical discharge drilling process with a micro vibration assisted on the hollow tube electrode which has been already repaired with several grooves on its side by wire electrical discharge machining (WEDM) while injecting air. This study also figured out the effect of the micro vibration assisted and the produced groove. Experimental results showed that the thickness of the gas film around the electrode became unstable because of the micro vibration, so that the chance of sparks which can take place around the electrode is reduced, ie., the bubbles from the air injected turned into the smaller bubbles and then this condition is hard to integrate into gas film. As a result, this developed process can improve the enlarging hole condition and the tapering hole phenomenon. In addition, because of the micro vibration, the bubbles can disperse averagely between the electrode and the hole. Thus the problem of the worse surface roughness of the performed hole also could be improved.
Subjects
ECDM
oversize
taping angle
surface roughness
micro vibration
Type
thesis
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