Electrical Discharge Grinding of Polycrystalline Diamond - Material Erosion Rate

Polycrystalline diamond (PCD) cutting tools is becoming more prevalent in aerospace manufacturing industries due to the emergence of carbon fiber-reinforced plastictitanium (CFRP/Ti) stack composites, which are now being used for the aerospace mainframes. Excellence mechanical properties of Ti require special tools in which PCD regarded as the best candidate. Ability to retain tools sharpness is an advantage of PCD cutting tools. However, the high thermal conductivity of diamond grains and low electrical conductivity become a challenge in PCD erosion process. This paper investigates the effects of machining polarity, as well as finishing in-feed, to the material erosion rate of PCD by Electrical Discharge Grinding (EDG). The experiment results show the role of carbon plating that happened on PCD surface when using positive polarity for the erosion. Through a scientific methodology and microscopic observation, it was found that the carbon plating phenomenon increased the material erosion rate and lowered the surface roughness value of the machine surface