Evaluation of Side Wall Roughness and Material Removal Rate in Vibration Assisted Powder Mixed Micro-EDM Drilling on Inconel 718

Micro-EDM drilling on difficult to machine materials has disadvantages like low MRR, high surface roughness, and others. In this manuscript the effect of two variants, workpiece vibration frequency and powder concentration in dielectric was applied together with the normal micro-EDM drilling operation. Voltage, Electrode Rotation Speed, Feed Rate, Workpiece Vibration Frequency, and Powder Concentration in Dielectric were taken as the five factors with Material Removal Rate (MRR) and Surface roughness along the sidewalls of the hole as the responses. Box Behnken design for five factors varied in three levels was taken as the experimental design. ANOVA was done on both the responses to find the significant factors and it was observed that all five factors were significant in both the cases. Multi-objective optimization using desirability approach was done and the optimum parameter setting was obtained. The optimized results were then validated with experiments and the relative error obtained was less than 4%.