Effects of electrical discharge energy on machining performance and bending strength of cemented tungsten carbides

This work elucidates the effect of electrical discharge energy on surface crack and bending strength of cemented tungsten carbide by electrical discharge machining (EDM). Cemented tungsten carbides graded K10 and P10 were used as workpiece materials, and the machining parameters of EDM were varied to study the effects of electrical discharge energy on material removal rate (MRR) and surface roughness. Moreover, the micro-cracks on the machined surface induced by EDM and the effects of electrical discharge energy on the bending strength were also examined. The experimental results reveal that the MRR increased with the electrical discharge energy. The surface cracks on the machined surface were more serious when the discharge energy was higher. The surface cracks and large discharge craters on the machined surface markedly reduced the bending strength. Thus, using EDM process to machine cemented tungsten carbides depends on carefully setting the machining parameters to prevent surface crack. (C) 2007 Elsevier B.V. All rights reserved.