Effect of Electrode Materials on Different EDM Aspects of Titanium Alloy

Abstract

Electro discharge machining (EDM) is extensively used in modern manufacturing industry because of its advantage over conventional machining method. Titanium alloys are the materials of research concern now for their extensive use in airframes and jet engines. Therefore, dimensional accuracy and surface integrity are the crucial concern for EDMed titanium alloys. The purpose of this study is to investigate the effect of process parameters and different type of electrodes on dimensional accuracy and surface integrity of EDMed Ti-5Al-2.5Sn titanium alloy. In this investigation, a comparative study has been conducted on the EDM performance of Ti-5Al-2.5Sn titanium alloy using different type of electrodes viz. copper, brass and zinc. The process performance has been measured by means of surface roughness (Ra), surface crack density (SCD), radial overcut (ROC) and recast layer. The outcome of using pulse on time, gap voltage, duty cycle, peak current as process parameters on the responses have been studied. Microstructural analysis has been carried out for the machined surfaces for different type of electrodes. Copper electrode provides a good surface finish and least radial overcut followed by brass and zinc electrodes. Thinner and uniform recast layer and higher surface crack density has been found on the EDMed surface machined by copper electrode compared to brass and zinc electrodes. Therefore, copper tool is recommended where higher precision and higher degree of surface finish is required for EDMed product.