Experimental Analysis on Wire Electrical Discharge Machinability of Electrically Conductive Silicon Carbide and Nitride as Function of Different Oil-Based Dielectrics

Abstract

Due to their high thermal, chemical and mechanical resistance, silicon nitride and silicon carbide are used as high performance components in tooling and chemical industries. Electrical Discharge Machining (EDM) is increasingly used for machining these ceramics, because conventional machining is restricted due to hardness and brittleness of the materials. State of the art has shown that wire EDM (WEDM) of ceramics is possible in water-based dielectric, but a porous and a foamy structure occurs on the surface, which can lead to a reduction in the mechanical load-bearing capacity. Previous own investigations have shown that the use of an oil-based dielectric does not lead to these structures, but the processing is not productive. Therefore, this paper deals with the influences of different oil-based dielectrics and different wire electrodes on the productive wire electrical discharge machinability and surface roughness of these ceramics. A standard technology with trim cuts is used to analyze the surface roughness achieved in the respective dielectric and with different wire electrodes under standard conditions.