Optimization of Surface Roughness and Surface Characterization of WED Machining of Titanium Ti-6Al-4V Alloy by Response Surface Method

Wire-Electric Discharge Machining (W-EDM) is one of viable advanced machining techniques for machining of hard materials like Titanium alloys precisely. It is critical to determine the optimum settings for control parameters to achieve desired levels of surface finish and dimensional tolerance. Considering this, this research investigates the effects of current, pulse on time (Ton) and pulse off time (Toff) on surface roughness (Ra) of WED machined Ti-6Al-4V alloy. The study showed that, increase in current from 2 A to 6 A resulted in increase of Ra by 13.92 % and increase in Ton from 20 μs to 50 μs caused an almost linear increase in Ra by 8.95 %. But increase in Toff from 20 μs to 30 μs led to a sharp reduction in Ra by about 20.44 %. Further, a regression model is developed to predict the surface roughness with R2=72.5%. The machined surfaces are characterised by the presence voids and microcracks on the recast layers, formation of microglobules, ridges and craters due to thermal effects.