Electric Discharge Machining of Cryo-Treated BeCu Alloys

Beryllium copper possesses high strength which produces severe problem of surface integrity and tool wear during machining by conventional machining process. Electrical discharge machining is a practically viable option to solve this problem. The present study investigates the effect of cryogenic treatment of work part along with gap current and external magnetic field on material removal rate (MRR) and tool wear rate (TWR). Blind 3 mm square holes were produced using electrolytic copper tool electrode to machine cryo-treated BeCu and untreated BeCu. Gap current is varied from 8 A to 16 A in a step of 2 amperes and magnetic strength is varied from 0 to 0.496 T in a step of 0.124 T. Based on the experimental results it was found that MRR increases with increase in gap current for both untreated BeCu and treated work part. Plotted graphs of cryo-treated work part showed high values of MRR in comparison to untreated work part. TWR increases for both treated and untreated BeCu work part with increase in gap current. But the TWR was less for cryo-treated work part in comparison to untreated work part. MRR and TWR increases for both treated and untreated BeCu work part with increasing magnetic strength. Again the MRR was found higher with lower TWR for treated workpiece with regard to magnetic strength. Thus it can be concluded that cryogenic-treatment with magnetic strength improves EDM machining efficiency.