Acoustic mechanism analysis of milling process through workpiece and spindle vibrations

Acoustic signals possess significant potential for online monitoring of tool wear conditions. However, the acoustic mechanism of milling remains unclear, posing significant challenges in the collection and noise reduction of acoustic signals, thereby reducing prediction accuracy. A comprehensive understanding of the mechanism underlying milling sound generation is essential. This paper designs a synchronous acquisition system for milling sound and vibration, analyzing the influence of workpiece and spindle vibrations on milling sound. A milling dynamic model and milling acoustic sound field model are developed to elucidate the relationship between workpiece vibration and milling sound. The results reveal that intermittent milling sound generation originates primarily from forced vibrations induced by periodic tool-workpiece interactions, exhibiting strong spectral correlations with tool tooth passing frequency and its harmonics. These findings provide critical theoretical foundations for optimizing acoustic-based tool condition monitoring systems through targeted signal denoising and frequency-domain feature extraction.