The Effect of Bearing Preload on the Lobes Diagram of High-Speed End Milling Process

The productivity of high-speed machining is often limited by chatter rather than by other process constraints when machining with end mills. Therefore, as spindle speeds have increased, capability of using the stability lobes diagrams to increase metal removal rates and precisely deciding the optimum spindle speeds in the design stage has become more essential. In this research, an integrated FEM stability model of high-speed end milling process considering high-speed effects is introduced and then an algorithm for generating the lobes diagram is developed. The results show that the first mode natural frequency increases at all speeds by increasing the rear bearing preload. Moreover, the allowable axial depth of cut is under-predicted if the high-speed effects are neglected. Finally, if the initial preload of the rear bearing set increases, the whole stability lobe shifts to the right with respect to the lobe of the original design.