Analysis of dimensional inaccuracies in square cavities generated on Ti-6Al-4V using planetary EDM

Dimensional accuracy of features generated by electro discharge machining (EDM) is influenced by process parameter combination as well as process instability. In present study, an attempt has been made to study the effect of process parameters viz. pulse ON time, tool path offset, scanning speed, pulse OFF time and gap voltage on overcut, internal edge radius and achieved cavity depth during planetary EDM of Ti-6Al-4V. Experimentations designed using Taguchi's L'16 standard orthogonal array has been carried out using copper as well as graphite electrodes. Results suggest that for both electrode materials, pulse ON time have relatively high statistical significance on overcut (51.7% and 34.9%) and internal edge radius (76.7% and 28.7%). However, cavity depth achieved is significantly affected by pulse ON time (15.7% for copper and 40.9% for graphite) as well as tool path offset (79.8% for copper and 33.2% for graphite).