Vibrations in stainless steel turning: multifractal and wavelet approaches

We investigate the experimental data of the turning process and the appearance of chatter vibrations. We focused on the turning of stainless steel as the example of a special material, which belongs to a hardly machinable class. To characterize the vibration properties we used statistical, multifractal, and wavelet analyses. The multifractal approach estimates complexity of the examined time series of the cutting thrust force. We report that the evolution of the vibration towards fairly large amplitude unwanted chatter with the increasing cutting depth coincides with lowering of the complexity. The results have been confirmed by continuous wavelet analysis.