Experimental Investigation on Parameters of Electro-Discharge Machining Of Alpha Titanium Using Copper and Graphite Electrodes

Abstract

Electro-discharge machining (EDM) method is an efficient process for machining of conductive materials using thermoelectric energy. Optimal adjustment of the input parameters in EDM including current, voltage, pulse period and electrode type affects the output characteristics such as material removal rate and surface roughness. The purpose of this study was to evaluate the surface quality and material removal rate of alpha titanium using EDM process with two types of copper and graphite electrodes. In this regard, full factorial design of the experiments (DOE) was carried out, and the input parameters were investigated as well as their interaction effects on the removal rate and surface roughness using the analysis of variance (ANOVA) statistical method. The results indicated that the electrode type, pulse sequence, current and voltage were the most important factors influencing the material removal rate, respectively. The effect of voltage on surface roughness was not significant. The use of graphite electrode results in a better surface quality than copper electrodes, while the copper electrode gives the material removal rate of 2.7 times higher than the graphite electrode. Optimal parameters were proposed for achieving favorite material removal rate and surface roughness during the roughing, semi-finishing and finishing stages.