Electrical Discharge Machined Surface of the Insulating ZrO2 Ceramics

Several insulating ceramic materials have been machined by electrical discharge machining (EDM) using the assisting electrode method that has been proposed by the authors' group. In this machining process, carbide products that are electrically conductive are made on the surface of workpiece. These products maintain the electrical conductivity of the workpiece surface during the machining process. The physical and mechanical characteristics of the layer were affected by the electrical machining conditions and by the physical characteristics of the workpiece. In this paper, three types of insulating ZrO2 ceramics were sintered and machined using sinking EDM in order to investigate the effects of different additive amounts on the machining properties of ZrO2-Y2O3 insulating ceramics. The material removal rate, wear ratio of the electrode, and the surface roughness were estimated. As the experimental factors, the ideal polarity of the electrode, setup discharge current, and Al2O3 additive amount were researched. The electrically conductive layer adhesion condition was recorded by SEM observation.