The Chatter suppression in this paper is based on the application of active dampers to a boring bar. The active damping system consists of 1) a pickup to detect chatter vibrations, 2) a driver with a computer and 3) piezoelectric actuators as a damper. In this system, the chatter vibration signals are fed to the computer. After the chatter frequency and phase shift parameter are calculated by the computer, these signals are supplied to the piezoelectric actuators with the same phase as that of the vibration velocity of the boring bar. As a result of this, the actuators can generate damping forces. If the chatter frequency changes or fluctuates, the computer, which constantly monitors the chatter vibrations, recalculates the phase shift parameter and instantly supplies the modified signals to the actuators. This boring bar system has been examined in cutting tests. It has been confirmed that the system has a great effect on the chatter suppression and adapts to change and fluctuation of the chatter frequency.
