Digital signal processing for self-vibration monitoring in grinding: A new approach based on the time-frequency analysis of vibration signals

Abstract

The occurrence of chatter can generate parts outside the dimensional and geometric tolerances or even cause irreversible damage, such as changes to the hardness and surface roughness of the ground part. The objective of this study is to propose a new vibration signal processing technique based on the short-time Fourier transform (STFT) and the ratio of power (ROP) statistic for the detection of chatter during the tangential surface grinding of AISI 1045 steel with different grinding wheels. Vibration signals were recorded at 2 MHz in the grinding tests. The Vickers hardness, roughness and metallography of the ground workpiece surfaces were also evaluated. A digital processing technique based on the STFT and ROP was applied to the vibration signals to extract the characteristics of the chatter. The results show that this technique can be used to characterize over time the spectral patterns of a frequency band related to chatter.