Acoustic emission signatures of electrical discharge machining

Relative to conventional machining processes, little is known about acoustic emission (AE) from electrical discharge machining (EDM). In light of the significant scope of AE in complementing electrical signals for the monitoring and control of EDM processes, the present research focussed on understanding AE from EDM in fundamental terms. AE waveforms are investigated in both single and sequential discharge formats with reference to pulse parameters, tool materials and dielectric media, to map AE signatures to process mechanisms. AE signals are further interpreted in terms of discharge forces, and the dynamics of gas bubbles observed through high-speed imaging of the gap.