EXPERIMENTAL INVESTIGATION OF MACHINING PARAMETER FOR WET & NEAR-DRY EDM FINISHING

The correct selection of manufacturing conditions and technique is one of the most important aspects to take into consideration in the majority of manufacturing processes and, particularly, in processes related to Electrical Discharge Machining (EDM). This paper investigate wet and near-dry electrical discharge machining to achieve the high fine surface finish. In near-dry EDM liquid and air mixture delivered through a tabular electrode instead of only liquid dielectric used in wet EDM. L-9 orthogonal array is applied to investigate the effect of discharge current, pulse on time, gap voltage and pulse off time on surface finish in wet and near-dry EDM. Pulse on time and discharge current are identified as a key factors for improving the surface finish in wet and near-dry EDM. Finally a, comparison for performance of wet and near-dry EDM has been made. It was experimentally found that near-dry EDM exhibits the advantage of good machining stability thus result in smooth surface finish at low discharge energy.