Machining characteristics of PCD by EDM with Cu-Ni composite electrode
Yue Teng, L. Li, Weishen Zhang, N. Wang, Chi Feng, Jun Ren
Abstract
Polycrystalline diamond (PCD) is widely used for its excellent properties but difficult to be processed by traditional machining methods. Electrical discharge machining (EDM) is regarded as an important method to machine PCD because of its non-contact nature. In this study, copper-nickel (Cu-Ni) electrode was prepared by electrodeposition and used to machine PCD. The machining characteristics of PCD including surface morphology, material removal rate (MRR) and surface roughness (SR) were studied in detail. Results show that the surfaces processed by Cu-Ni electrode have a larger radius but shallow craters and less cracks than that by Cu electrode. The MRR of PCD by Cu-Ni electrode is 252% higher than that by Cu electrode, and the SR is 18% lower than that by Cu electrode after processing at low parameter value while they are 6% and 15% at high parameter value, respectively. The result indicates that graphitization of diamond dominates the removal process when processing by Cu-Ni electrode; however, when processing by Cu electrode, the principal cause of the diamond exfoliation was the fusion of the cobalt binder and explosion. This research provides an essential experimental basis for designing technics of precision and highly efficient electrical discharge machining PCD tools.