Abstract
Polycrystalline diamond (PCD) is widely used to fabricate cutting tools. In the electrical discharge machining (EDM) of PCD, thermal damage, such as graphitization of diamond grains, is a critical problem. In this study, we performed EDM of PCD using rotary cupronickel electrodes and investigated the structural changes of PCD by Raman spectroscopy. It was found that the PCD surfaces machined using the rotary cupronickel electrodes were smoother than those in conventional EDM. The results also showed that diamond graphitization decreased when electrical discharge energy decreased and/or when feed rate increased. In order to reduce graphitization of diamond, we proposed a dry EDM finishing method for PCD. Very low surface roughness and low thermal damage were successfully achieved.
