A Control System for Chatter Avoidance by Ramping the Spindle Speed

This paper presents a new control system for chatter avoidance in milling. The control system monitors the cutting process using a statistical indicator named the R-value which is computed from the cutting force signal. When chatter is detected, the control system ramps the spindle speed in search of a speed at which chatter ceases. The system does not involve time consuming computations and therefore is suitable for on-line implementation. Also, it does not interrupt the cutting process by halting the feedrate or the spindle speed. Simulations showed that the control system has a significant chatter avoidance potential in the high speed range, and also for partial and full immersion cuts. The system was implemented successfully to avoid chatter in slotting and half immersion down milling.