Fabrication of Polycrystalline Diamond Three-dimensional Structures by Sinking EDM Using Carbon Diffusion Reaction

Abstract

In our previous report, the electrical discharge machining (EDM) of polycrystalline diamond (PCD) using a carbon diffusion reaction with transition metal electrodes was proposed. The material removal rate and surface roughness were improved using a rotary cupronickel electrode for finish machining. In this work, we performed sinking EDM of PCD with a piezo-electrically vibrated cupronickel electrode for microstructure generation. Results showed that the material removal rate was improved by 2.3 times compared with a copper electrode even in rough machining. By observation of the machined surface and removed debris, it was found that molten cupronickel induced the carbon diffusion reaction and the promoted graphitization of diamond grains. Precise three-dimensional structures of PCD were successfully fabricated by vibration-assisted sinking EDM using the cupronickel electrode.