Electrical Discharge Machining for Sintered Polycrystalline Diamond using Bi-polar Pulse Generator

Abstract

Sintered polycrystalline diamond (PCD) is widely employed for cutting tools because of its great hardness and high wear resistance. However, it is extremely difficult to shape PCD tools by conventional machining methods. We describe the truing of a PCD tool by electrical discharge machining (EDM). Although EDMing of PCD is possible under the PCD positive polarity, the removal rate is relatively low. In this paper, we discuss the possibility to apply the bi-polar pulse for the EDMing of PCD. It is confirmed that the removal rate of PCD using the bi-polar pulse is higher than using normal pulse(electrode positive or negative polarity). Moreover, the electrode wear ratio is also improved.