Electro discharge machining of PCD using rotating cemented carbide electrode mounted on ultrasonic spindle

摘要

Polycrystalline diamond (PCD) is made by sintering fine diamond particles with cobalt as a sintering aid. When a blind-hole is machined into a standard PCD (S-PCD) workpiece using die-sinking EDM it is not possible to remove the nonconductive diamond part. Consequently, machining efficiency is poor and the electrode wear is large on S-PCD. On the other hand, boron-doped diamond particles showed good discharge ability. This second type of PCD material is named electrically conductive polycrystalline diamond (EC-PCD). Authors decided to focus on EC-PCD through the creation of ultrasonic vibration assisted electro discharged machining (EDM). Consequently, the machining efficiency of EC-PCD was enhanced and the electrode wear was reduced. In this study, an ultrasonic vibration assisted EDM using a rotating cemented carbide electrode is proposed for machining the two types of PCDs. Characteristics of blind-hole machining to each PCD were investigated.