Feasibility study of through hole fabrication on aluminium nitride ceramic using die-sinking electro-discharge machining

Abstract

A series of experiments were carried out to machine aluminium nitride (AIN) ceramic by die-sinking electro-discharge machining (EDM) process. EDM is a non-conventional machining process that requires the workpiece to be electrically conductive. An assisted-electrode method is used to make the surface of the workpiece conductive enough to machine. A combination of graphene paste, carbon nanotube, and copper tape has been used to make the coating surface. Tungsten carbide tool has been used. The findings indicate that, for low pulse energy, it is possible to generate through holes in this process. A combination of low peak current and high gap voltage proved to be successful in this method. The surface of the machined hole reveals that thermal spalling is present as material removal mechanism, which results in a rough surface. The energy dispersive spectroscopy (EDS) analysis proves that carbon deposition occurs in the wall of the holes to promote successful machining. Copper is also present in the machined surface. A feasible process has been developed to machine AIN ceramics using EDM process.