Optimization of Process Parameters in Micro-EDM of Ti-6Al-4V Alloy

Titanium alloys are categorized as light weight materials posse greater strength and toughness and are usually known to create major challenges during conventional and non-conventional machining. In general, these alloys are referred as difficult to machine materials. Titanium alloy (Ti-6Al-4V) suffers poor machinability for most cutting processes, especially the generation of micro-holes using traditional machining methods. Electrical Discharge Machining (EDM) is suitable for machining titanium alloys, although selection of machining parameters for higher machining rate and accuracy is a challenging task in machining micro-holes. Discharge current, pulse ON time and Flushing pressure were considered as the major influencing machining parameters and Material Removal Rate (MRR), Tool Wear Rate (TWR) and Hole Taper were considered as the performance criteria. It is observed that machining performances are affected mostly by the peak current and pulse-on time during micro-electro discharge machining of titanium alloy. Mathematical models have been developed using multiple regression analysis, to establish the relationship between various significant process parameters and micro-EDM performance criteria. Also, studies have been made to examine the influence of various process parameters on the quality of the machined micro-hole.