Optimization of Process Parameters on Ti-6Al-4V Using Central Composite Design Method

Electrical discharge machining (EDM) is relatively modern machining process having distinct advantages over other machining processes and able to machine Ti-alloys effectively. This paper attempts to investigate the effects of process parameters on output response of titanium alloy Ti-6Al-4V in EDM utilizing copper tungsten as an electrode and positive polarity of the electrode. Mathematical models for material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) are developed in this paper. Design of experiments method and response surface methodology techniques are implemented. The validity test of the fit and adequacy of the proposed models has been carried out through analysis of variance. It can be seen that as the peak current increases the TWR decreases till certain ampere and then increases. The excellent surface finish is investigated in this study at short pulse on time and in contrast the long pulse duration causes the lowest EWR. Long pulse off time provides minimum EWR and the impact of pulse interval on EWR depends on peak current. The result leads to wear rate of electrode and economical industrial machining by optimizing the input parameters. It found that the peak current, servo voltage and pulse on time are significant in material removal rate and surface roughness. Peak current has the greater impact on surface roughness and material removal rate.