Study of vibration-assisted micro-EDM - The effect of vibration on machining time and stability of discharge

In micro-EDM (electric discharge machining), due to the improper flushing out of the debris, frequent adhesion between a tool electrode and a workpiece prevents the continuation of the machining. Thus, a long time is required for machining, even when the machining is possible. In order to solve this problem, we introduced vibration-assisted machining to micro-EDM using PZT in an attempt to flush out debris from the gap between a tool electrode and workpiece. The results indicate that vibration assistance improves the machining stability and results in an extreme reduction of the machining time. In this study, we describe the effects of vibration-assisted micro-EDM on machining time for a range of amplitudes and frequencies. We next show the results of the discharge current and displacement of the machine table in machining, in order to prove that the machining instability comes from the adhesion between a tool electrode and a workpiece. In addition, we also showed a close relation between the stiffness of the workpiece and the adhesion phenomenon. To validate our experimental results, a small square shaft was successfully fabricated by vibration-assisted micro-EDM. (C) 2007 Elsevier Inc. All rights reserved.