Use of the grey-Taguchi method to optimise the micro-electrical discharge machining (micro-EDM) of Ti-6Al-4V alloy

This article demonstrates the effectiveness of optimising multiple quality characteristics (electrode depletion (ED), material removal rate (MRR) and overcut) to achieve a better finish quality for micro-electrical discharge machining (micro-EDM) of Ti-6Al-4V alloy, using the grey-Taguchi method. The effect of various cutting factors (peak current, pulse on-time, pulse off-time and gap) on the ED, MRR and overcut for micro-EDM of Ti-6Al-4V alloy is analysed. The experimental results show that the peak current and pulse on-time are the most important factors in the micro-EDM of Ti-6Al-4V alloy. The optimum conditions for good multiple performance characteristics for the micro-EDM of Ti-6Al-4V alloy, A1B1C3D3, are a peak current of 0.3 A, a pulse on-time of 6 μs, a pulse off-time of 13 μs and a gap of 40 V. The ED is decreased from 129.1 to 70.6 μm, the MRR is decreased from 8.58 to 4.05 × 10−4 mm3/min and the overcut is decreased from 20.00 to 16.23 μm. The use of the grey-Taguchi method results in clear improvements in ED and overcut.