Analysis of the Influence of Discharge Distribution and Wire Movement on Wire Breaks during WEDM

Wire electrical discharge machining (WEDM) is widely used for high-precision manufacturing but remains limited in productivity by unpredictable wire breakage. The risk of wire failure is particularly high during the main cut, where elevated thermal loads from intense discharge activity coincide with mechanical stresses caused by wire tension, flushing, and vibration. This work presents an in-situ high-speed imaging approach for analyzing discharge activity and wire behavior in the temporal vicinity of wire breakage under realistic main-cut conditions. The accuracy and limitations of camera-based discharge detection are evaluated through comparison with electrical measurements, explicitly accounting for sampling-related effects. Discharge pulse areas are analyzed to characterize their statistical distribution and temporal evolution prior to wire breakage, revealing an increase in the aggregated rolling mean pulse area toward failure that is statistically supported at an exploratory significance level. Wire vibration measurements from a representative dataset provide characteristic amplitude and frequency ranges but do not yield a statistically robust precursor when considered in isolation. High-speed recordings further show that discharge activity can persist transiently after wire breakage and migrate along the workpiece surface, indicating a potential risk to surface integrity beyond productivity loss.