Development of Arrayed Structures Using Reverse EDM (R-EDM)

Abstract

In recent years, reverse electric discharge machining (R-EDM) has been developed as a method for the fabrication of arrayed structures which find applications in the fabrication of fins and component assembly. In this study, the feasibility of R-EDM process in the fabrication of arrayed features of Ø 3 mm and height 2 mm on mild steel has been studied through response surface methodology (RSM) based experimentation. The influence of machining parameters i.e., peak current (Ip), pulse-on time (Ton) and flushing pressure (Fp) on some of the vital response characteristics like material removal rate (MRR), surface roughness (SR), taper, cylindricity error and micro hardness and surface morphology of the pillared structures has been investigated. Further, a hybrid optimization method i.e., principal component analysis (PCA) based grey relational analysis (GRA) technique, is utilized to obtain optimal parameter combination with an aim to improve machining conditions for fabrication of arrayed features during R-EDM process. Analysis of variance (ANOVA) results shows that Ip has significant effect followed by Ton on MRR and Ip has major contribution towards SR, taper and cylindricity error. Micro hardness has maximum value in heat affected zone (HAZ). The optimal parameter combination based on PCA based GRA is found to be Ip = 10 A, Ton = 100 µs and Fp = 0.3 kg/cm2 which was further ascertained using confirmatory test