Tool edge Chipping Monitoring Method based on Synchronous Envelope Orientation Mapping

Reliable detection of initial tool edge chipping in precision milling remains a critical challenge, as subtle fault features are often submerged in strong background noise and runout interference. To address this, this study proposes a novel vibration monitoring framework: Synchronous Envelope Orientation Mapping (SEOM). The methodology begins with an amplitude maximization strategy for strict integer-period truncation to ensure spectral accuracy. A narrowband synchronous envelope algorithm is then applied, specifically extracting higher-order edge-pass harmonics to decouple chipping-induced impacts from low-frequency eccentricity. The resulting energy distribution is visualized via polar orientation mapping, generating intuitive "petal diagrams" that reveal the health status of individual cutting edges. Furthermore, to overcome the limitations of manual visual inspection, a quantitative metric named the Polar Asymmetry Factor (PAF) is constructed to automatically assess damage severity. Results indicate that the PAF maintains high sensitivity even for micro-chipping (0.2 mm) and exhibits a monotonic positive correlation with fault evolution, providing a robust and interpretable solution for intelligent tool condition monitoring.