Application of spindle speed variation for chatter suppression in turning

In the present paper the chatter instability of variable speed machining is studied. Though, there exist numerical methods for the computation of the stability lobes for variable speed machining, especially in turning processes the potential of an active spindle speed variation for chatter suppression is mostly unexploited. In the case of a slowly time-varying spindle speed, which is practicable on a real machine tool, the stability behavior with a time-varying spindle speed is connected to the stability behavior with constant spindle speeds. This so-called frozen time approximation helps to understand the stabilizing mechanism of turning with spindle speed variation. Strategies for tuning the parameters of the speed variation for an optimal stabilization are developed. The results presented here are useful for a practical implementation of variable speed machining to increase the productivity without any negative effect due to the variation of the spindle speed.