EDM of titanium foam: electrode wear rate, oversize, and MRR

Abstract

ABSTRACT This article intends to give the prospect of machining Ti foam using electrical discharge machining (EDM) process. Closed-cell titanium foam with average cell size of 5 μm and pure brass are selected as workpiece and tool electrode material, respectively. Two different shapes of tool electrode, hollow and chamfer shaped electrode, are selected for this study. The EDM input factors such as discharge time, current, and discharge voltage are selected as input measures; electrode wear rate, oversize, and MRR are taken as outcome measures. Current demonstrates major influence on electrode wear rate compared to discharge time and discharge voltage. A linear regression model is proposed to predict the wear of electrode for varying blends of input process variables. The proposed model predicts electrode wear at R2 value of 81.5% and 75.8% for hollow and chamfered electrode, respectively. The wear features of machined tool electrode and oversize are analyzed using the microscopic images. The micrograph reveals that hollow electrode experience severe inner edge wear, whereas chamfered electrode undergoes more front wear. The chamfered electrode produce hole with oversize of 0.43% and 0.4% at entry and exit, respectively. Maximum MRR is obtained using hollow electrode.