Suppression of chatter vibration by unequal pitch turning applying estimated cutting force

Abstract

Multi-tasking machine tool with multi-turret is attracting a great deal of attention, which can offer higher efficiency and higher accuracy. However, chatter vibration generated during parallel turning with two tools might be one of the bottlenecks for higher material removal rate. To suppress chatter vibration, we proposed unequal pitch turning method in this research. In this method, the upper tool was properly controlled based on optimum pitch angle calculated from spindle speed and chatter frequency. Chatter frequency was identified from estimated cutting force by disturbance observer. From the result of parallel turning test, it is clear that chatter vibration can be suppressed by controlling the upper tool based on optimum pitch angle.