Multi-channel electrical discharge machining of titanium alloy Ti-6Al-4V with semiconductor electrodes

Abstract

Titanium alloys are extensively used in aerospace and medical engineering owing to their exceptional mechanical properties and biocompatibility. For a long time, the low thermal conductivity of titanium alloys has made them difficult to machine with conventional approaches. Electrical discharge machining (EDM) is a nonconventional method for machining difficult-to-cut materials. However, it is not possible to achieve high-quality surface finish while simultaneously maintain high machining efficiency. This paper introduced a new EDM approach to obtain high surface quality in machining titanium alloy Ti-6Al-4V with discrete semiconductor electrodes by utilising a new multi-channel discharge principle to disperse the discharge energy. To explore the dissimilarities in discharge characteristics between semiconductor electrodes and traditional copper electrodes, continuous discharge waveforms of both electrodes were compared. Through modelling the discharge equivalent circuit and analysing workpiece surface using scanning electron microscopy (SEM), it was discovered that, due to the unique electrical properties of the semiconductor, it is possible for semiconductor electrodes to form multiple discharge channels. The outcomes reveal that the utilization of semiconductor electrodes can disperse discharge energy and enhance surface quality without sacrificing material removal rate compared to the use of conventional copper electrodes.