Experimental investigations into near-dry milling EDM of Stellite alloys

This study investigates the feasibility of near-dry milling electrical discharge machining (EDM) of Stellite alloys as a post-processing operation. Stellite is a group of hard cobalt-based alloys which are widely used in industry due to good wear and corrosion resistance, as well as their ability to withstand high temperatures. The design of experiments (DoE) technique is employed to study the effects of discharge peak current, pulse duration, air pressure in the dielectric mist and parallel capacitance in the discharge circuit on the response variables such as material removal rate (MRR), tool wear ratio (TWR), and surface roughness (evaluated through Ra and Rt values). Experimental data analysis demonstrates that the discharge peak current has a stronger effect on the machining performance than the other factors. Higher discharge peak current yields higher MRR, lower TWR, but lower surface quality.