Wire-Cut Electrical Discharge Machinability of Ceramics

摘要

THe wire-cut electrical discharge machinability of four ceramics was evaluated. Titanium diboride and silicon carbide workpieces were successfully cut in the monolithic state. Boron carbide could only be cut when a metallic sandwich structure was placed around the workpiece. Silicon nitride could not be successfully cut. Mechanisms of material removal as well as a minimum level of workpiece electrical conductance necessary for EDM are proposed. Characterization of the surface damage resulting from electrical discharge machining is presented. Recast, partially melted, and heat affected zones are identified. The effects of parametric processing variations on surface integrity are discussed. Flexure strength and residual stress data are compared for EDM cut and diamond ground surfaces in titanium diboride. Certain limitations are proposed for the EDM fabrication of ceramic components where surface defects are strength limiting.