Electrical Discharge Machining of Metal Matrix Composites with a High Speed Non-Round Electrode

Abstract

An electrical discharge machining process with a high electrode rotation speed (EDM-HS) has been developed to solve the problems of the conventional EDM process in machining metal matrix composites (MMCs). The EDM-HS process employs a non-round tool electrode. The experiment results showed that the materials removal rate (MRR) of the workpiece can be improved significantly by employing a non-round tool electrode. The relationship between the pulse duration, machining current, duty cycle, the rotation speed of the tool electrode and the MRR has been studied respectively. And the machining mechanism of this EDM-HS process has been analyzed both theoretically and experimentally. The results showed that the non-round electrode can enlarge the machining gap and with a high electrode rotation speed, the machined debris can be discharge out of the machining area effectively and hence a stable machining condition can be obtained. As a result, a higher MRR can be achieved. Moreover, an orthogonal analysis has been utilized to study the relative importance of the machining parameters on MRR. It was found that to obtain the highest MRR, the electrode rotation speed was the most influential factor among the duty cycle, machining current, pulse duration and electrode rotation speed. This outcome supports that it is feasible to use this novel method to machining particulate reinforced MMCs, where a higher MRR can be achieved.