Micro Electrical Discharge Milling of Titanium: Effects of Voltage and Tool Rotation Speed

Abstract

Micro electrical discharge milling (µED-milling) is gaining a tremendous reputation due to its capability of fabricating intricate shapes with a simple rotating tool. Its unique advantage of machining any electrically conductive material makes it applicable for processing high strength materials like titanium (Ti) and its alloys. The present study investigates µED-milling of Ti grade 2 alloy using tungsten carbide as a tool electrode. The effect of important process parameters like voltage and tool rotation speed (TRS) is examined by evaluating response measures such as material removal rate (MRR), tool wear rate (TWR) and electrode wear ratio (EWR). MRR and TWR increase with an increase in both voltage and TRS due to a rise in discharge energy and better flushing of eroded particles from the machining zone. Highest MRR of 268,232 µm3/s and lowest TWR of 27,845 µm3/s is achieved at highest (200 V and 2000 rpm) and lowest (110 V and 500 rpm) parametric combination, respectively, considered in this study. EWR decreases with an increase in voltage, whereas EWR has a negligible variation with an increase in TRS. The lowest EWR of 0.199 is achieved at a voltage of 200 V and TRS of 500 rpm.