Electrical discharge machining of polycrystalline diamond (PCD)

This paper reports the experimental investigations of the effect of setting parameters of EDM on the material machining rate, the tool electrode wear ratio and surface roughness of PCD blanks. The machining feed rate of EDM of PCD layer is substantially lower than that of WC substrate. The estimation of the thermal stress in the diamond grain and cobalt phase shows that the difference between the coefficients of thermal expansion of diamond and cobalt is significant factor in the diamond grain removal mechanism during electrical discharge machining of PCD. Energy dispersive spectrometry (EDS) revealed that some amount of the synthetic diamond on machined surface is graphitized.