Effect of Cryogenic Treatment of Copper Electrode on Electro-Discharge Machining

Cryogenic treatment is an ultra low temperature treatment technique. Effect of cryogenic treatment on properties of ferrous materials and alloys is well understood. Due to which, cryogenic treated materials are being used in various applications. One among them is Electro-Discharge Machining (EDM). In EDM, the replica of electrode is obtained on the work piece, during the process tool also worn out to certain extent. In order to reduce the tool wear rate cryogenic treatment can be applied to the tool material. In this paper, the effect of cryogenic treatment on electrode wear rate of electro-discharge machining for varied pulse ON time (EDM) was studied. The cryogenic treatment was applied to the copper electrode and the microstructure analysis was carried out using optical microscope. EDM experiment was conducted using untreated and cryogenic treated copper as electrode and High Speed Steel (HSS) as work piece. Electrical resistivity was also measured. From the microstructure analysis it was inferred that the grains of cryogenic treated electrode are smaller than that of the untreated sample. Electrode Wear Rate (EWR) was found to be reduced and Material Removal Rate (MRR) was improved due to cryogenic treatment. This can be related to the reduction in electrical resistivity of cryogenic treated copper electrode.