An Experimental Investigation of Powder Assisted Electrical Discharge Machining of Mild Steel & Inconel 718 and Parametric Optimization

Abstract

Electrical Discharge Machining which is a non-conventional machining process have been introduced lately as a hybrid one assisted by techniques like ultrasonic vibration, addition of abrasives etc. Application of these techniques infused with traditional EDM has enhanced machining characteristics i.e. Material Removal Rate (MRR), Surface Roughness (SR), Tool Wear Rate (TWR). This work is based on investigating the machining characteristics, of a graphite Powder Assisted Electrical Discharge Machining on Mild Steel & Inconel 718 with Mobil Velocite Oil No 04 as the dielectric medium. The responses measured in the experiment are Material Removal Rate, Surface Roughness and Tool Wear Rate whereas the factors have been Pulse-On Time, Pulse-Off Time and Peak Current. Increase in Peak Current as well as Pulse-On Time resulted in increased Material Removal Rate but decreased surface quality and tool surface integrity. The results of the machining characteristics of Powder Assisted EDM have been analyzed by means of Response Surface Methodology; Analysis of variance (ANOVA) and F-test has been used to check the validity of regression model and determined the significant parameters affecting the machining characteristics. The numerical optimization of the factors and prediction of responses have also been duly observed.