Study of Electrode Wear Ratio of Piezoelectric Self-adaptive Micro-EDM

Micro Electrical discharge machining (Micro-EDM) is a non-traditional concept of machining. It is very suitable for machining micro parts of Micro-electromechanical Systems (MEMS). However, the application of micro-EDM is restricted for its own shortcomings such as poor material removal rate and high electrode wear ratio etc. In order to overcome this shortcoming, a new piezoelectric self-adaptive micro-EDM (PSMEDM) is developed based on inverse piezoelectric effect of piezoelectric ceramics and its working mechanism and characteristics have been analyzed in this paper. This machining method can realize the self-tuning regulation of discharge gap depending on the discharging conditions, facilitate removing the debris in the machining gap, reduce the occurrence of arcing and shorting and can realize the self-elimination of short circuits, thus the machining efficiency can be improved drastically. The tool electrode wear ratio (EWR) in machining is studied in this paper. Many experiments have been done and the effects of parameters on electrode wear ratio have been analyzed. Experimental results indicate that: 1) The EWR will rise with the increase of open-circuit voltage and main capacitance in circuit because the increase of open-circuit voltage and capacitance result in increase of single discharge energy. 2) The effect of resistance R1 on EWR is light. With the increase of resistance R1, the EWR will decrease slightly. 3) With the increase of resistance R2, the EWR will decrease firstly and then becomes to increase.