Abstract: The principle of suppressing chatter by cutting with varying spindle speed is discussed sysmatically based on studying the regularity of vibration response of the machining system under the excitation with fluctuating frequency. It is proved by theory analysis and experiment results that the vibration response in the cutting process with varying spindle speed is the one of the machining system under the excitation with fluctuating frequency, which is far smaller than that of the excitation with constant frequency, this is the more essential mechanism of suppressing chatter why the vari-speed cutting has obvious effects on vibration control.

Key words: Cutting, Excitation with fluctuating frequency, Machine tool, Suppressing machining chatter, Varying spindle speed