The effects of cold and cryogenically treated copper electrodes and beryllium-copper alloy workpieces on the performance of electro discharge machining

In this study, the effects of cold and cryogenically treated copper electrodes and beryllium-copper alloy workpieces on the performance of electro discharge machining (EDM) were investigated experimentally. Copper (Cu) electrodes and beryllium-copper (Be-Cu) alloy workpieces were subjected to -100°C for cold treatment and -185°C for cryogenic treatment. It was observed after cold and cryogenic treatments that the grain size of copper electrodes and beryllium-copper alloys were increased, microhardness of the materials were reduced, electrical conductivity of copper electrodes were reduced, electrical conductivity of beryllium-copper alloy workpieces were increased, crystal structure of the materials were changed and thermal expansion of the copper electrodes were reduced. EDM tests were conducted on 10A, 15A, 20A and 25A currents and 20µs, 40µs, 60µs and 80µs pulse durations. EDM performance was increased by increasing of material removal rate and by decreasing of electrode wear ratio, surface roughness and white layer thicknesses by employing cold and cryogenically treated copper electrodes and beryllium-copper workpieces.Key Words: Cold treatment, cryogenic treatment, EDM