Comparison of performance of different tool electrodes during electrical discharge machining

Abstract

In this work, performance of tool electrode prepared through selective laser sintering (SLS) process has been studied along with traditional copper and brass electrodes for electrical discharge machining (EDM) of AISI 1040 stainless steel. Performance measures like material removal rate (MRR), tool wear rate (TWR), radial over cut (ROC) and average surface roughness (R_a) of the machined surface have been considered. Multi-response optimization like technique for order preference through similarity to ideal solution (TOPSIS) method has been used to find out the best parametric setting of the EDM process for maximization of MRR and minimization of TWR, ROC and R_a. Scanning electron microscopic (SEM) images of the machined surface reveals that less surface crack density (SCD) has been formed on the machined surface by the use of AlSiMg RP tool electrode followed by brass and copper tool electrodes. Although MRR decreases with the use of AlSiMg tool electrode, good surface finish with less surface crack density on the machined surfaces has been observed as compared to other two tool electrodes. SEM and EDX analysis of the machined surfaces by different tool electrodes reveals presence of tool materials on the machined surfaces with increased carbon content. Therefore, it has been recommended that AlSiMg tool electrode can be conveniently adopted for finishing and semi-finishing operations.