Effect of Short-Circuiting in Electrical Discharge Machining of Carbon Fiber Reinforced Plastics

In this paper, we investigate the effects of short-circuiting on machining in order to discuss material removal in EDM of CFRP. Sinking EDM of CFRP using deionized water was carried out, and waveforms of gap voltage and current, pulse frequency and servo feed fluctuation, were measured for classifying machining situations, electrical discharge and short-circuiting. The cause of short-circuiting and the relationship between the short-circuiting ratio and material removal rate were investigated. In addition, the potential drop and temperature of short-circuiting carbon fibers were estimated with a simple model. Experimental results show that short-circuiting due to frayed carbon fibers frequently occurs in sinking EDM of CFRP. It is found that the short-circuiting contributes to the material removal in EDM of CFRP.