On the Relation between the Fluctuation of the Rotational Speed or the Workpiece and the Fluctuation of the Frequency of the Self-Excited Machine Tool Vibration

Abstract

The instantaneous rotational speed of the workpiece and the instantaneous frequency of the self-excited machine tool vibration are measured by an apparatus developed by the authors based on the demodulation of frequency modulated signals. It is experimentally shown that the rotational speed fluctuates periodically because of the slippage of a belt in the driving train and the frequency fluctuates with similar time-history to that of the rotational speed to maintain a constant cycle per rotation of the workpiece. It is concluded that the similarity of the time-history is brought about by the fact that the frequency follows the fluctuation of the rotational speed. It is finally pointed out that making clear the cause that makes the frequency follow the rotational speed is necessary to get full understanding of the self-excited machine tool vibration.