Analysis of the effect of vibrations on the micro-EDM process at the workpiece surface

In this study, the effect of vibrations on the electrical discharges in the micro-EDM (electrical discharge machining) process was investigated. The electrical discharge machining of micro bores was chosen to represent a typical application. Using sophisticated measuring equipment to record and analyse current and voltage waveforms as well as electrode feeding during the process, deeper insight into the discharge mechanisms was achieved. It was found, that the micro-EDM boring process can be subdivided into three major parts, the start-up process, the major boring process and the workpiece breakthrough of the tool electrode. Extensive investigations have shown a delayed start-up process on the workpiece surface for conventional micro-EDM; however, this effect can be reduced by inducing vibration on the workpiece. The cause of this reduction was analysed by single discharge analysis which also provides a means to investigate the effect of vibration frequency.