An Experimental Study on Electrical Discharge Machining of Copper Alloy Grade HR750

Abstract

Electrical discharge machining process (EDM) is a process for removing material by the thermal of electrical discharge. EDM process melts and evaporates workpiece material. Some of the melted and all of the evaporated material is then quenched and flushed away by dielectric liquid and the remaining melt recast on the finished surface. The recast layer is called as white layer. Beneath the recast layer, a heat affected zone is formed. The quality of an EDM product is usually evaluated in terms of its surface integrity, which is characterized by existence of surface cracks and residual stresses. The machinability of EDM in terms of the material removal rate and electrode wear ratio was evaluated in this paper. The machining tests were carried out on a copper alloy grade HR750 with a copper tungsten electrode. The workpiece surfaces are analyzed by optical microscope and XRD technique. The formation of crack is not found.