Effects of Machining Parameters on Performance Characteristics of Powder Mixed EDM of Inconel-800

Abstract

This research work explores the connection of machining parameters, i.e. peak current (Ip), pulse on-time (Ton), pulse off-time (Toff), tool material (copper, copper-chromium, graphite) and powder particles (tungsten carbide, cobalt, boron carbide) on surface roughness (SR) for Inconel-800 superalloy in powder mixed electrical discharge machining process (PMEDM). The Box–Behnken design had been applied to design the experiments, and response surface methodology (RSM) was employed to cultivate the empirical models. Forty-six experiments were conducted as per Box-Behnken method of RSM. The results indicated that when current increases from 4 to 12 A, SR increases from 4.23 to 12.57 μm, while with the increase of Toff from 30 to 60 μs, SR decreased from 9.23 to 7.10 μm. Results also indicated that copper as a tool electrode and boron carbide as a powder additive has significantly effect on SR. The predicted results based on developed models are found to be in good agreement with the experimental results reasonably well with the coefficient of determination 0.96 for surface roughness. Furthermore, certain machined specimens were analyzed using energy-dispersive x-ray analysis (EDX) and scanning electron microscope (SEM) techniques.