Bearing Nonlinearity and Stability Analysis in High Speed Machining

Elimination of chatter is an important problem for the successful implementation of high speed machining. Chatter is often related to the dynamic characteristics of the spindle system. The current study addresses the dynamic characteristics of angular contact bearings, which are the most commonly used type for high speed spindles, with respect to the speed change at high speeds, and reveals a very important fact on how the stiffness changes with respect to the speed change. It also illustrates how this characteristic is related to the system stability. Both analytical and experimental results show that there is a substantial change in stability zones in the high speed range and that the speed varying dynamic characteristics of a spindle must be properly taken into consideration in order to select a stable machining speed in high speed machining.