Real-time evaluation of gap flushing in electrical discharge machining

This paper reports on acoustic emission (AE) from electrical discharge machining (EDM) in the context of gap flushing, and demonstrates its sensitivity to gap contamination from both metallic debris and gas bubbles. AE is further shown to relate to the local medium (liquid or gas bubble) through which individual discharges occur, and hence comprise unique and valuable process information on the effectiveness with which material is removed at the scale of a single discharge. This enabling technology is readily implemented for the in-process quantification, monitoring and optimization of flushing, and may constitute the basis for flushing-related adaptive control of EDM.