Optimisation of Current and Pulse Duration in Electric Discharge Drilling of D2 Steel Using Graphite Electrode

Abstract

Electric discharge machining (EDM) is one of the viable techniques for machining of D2 steel, in which the material removal occurs by spark erosion. The poor selection of EDM parameters affect the machining quality and productivity. Considering this, the present work investigates the effect of current, charging and discharging time on the material removal rate (MRR) and the surface roughness (R_a) while machining of D2 steel using graphite electrode. The results were analysed using statistical methods to identify the effect of control parameters and to optimise the settings. The study shows that MRR and R_a was significantly influenced by current. At optimum settings, the MRR and the R_a obtained was 38.16 mg/min and 3.39 µm respectively. Morphological analysis of the machined surface show that the size of the globules formed decreased with increase in current.