Experimental Investigations into Traveling Wire Electrochemical Spark Machining (TW-ECSM) of Composites

Fiber reinforced composites, though relatively new, have already become important engineering materials. So far the main emphasis of research has been on the development of materials, but nowadays more attention is being paid to the industrial manufacture of products made of composites. Conventional machining methods and some unconventional machining methods like laser beam machining (LBM) and water jet machining (WJM) cannot be effectively applied for machining of composites due to the resulting problems of air borne dust, tool wear, and thermal damage. Recently electrochemical spark machining (ECSM) has been applied for the cutting and drilling of holes in composites. The success achieved in the application of ECSM for cutting of composites has stimulated interest in exploring the prospects of use of traveling wire electrochemical spark machining (TW-ECSM) process for cutting of composites. An apparatus for TW-ECSM is designed and fabricated in the laboratory. The results about the feasibility of the process and its performance during machining of composites are presented in this paper. Experiments are carried out on glass-epoxy and kevlar-epoxy composites, using sodium hydroxide (NaOH) as electrolyte. The wire and the workpiece were kept in physical contact with each other by the use of a gravity feed mechanism. The effects of voltage and concentration of the electrolyte on material removal rate, average diametral overcut, tool wear rate, and wire erosion ratio are reported. The theoretical analysis of the mechanism of the process identifies the thermo-mechanical phenomena as the main source of material removal in ECSM.