High Speed Process Damping in Milling.

High performance milling processes are limited by two dominating factors: the available spindle power and the dynamic stability of the process. When the cutting depth exceeds the stability limit chatter vibrations arise. These vibrations lead to wavy surfaces, increase of the tool wear, acoustic noise and can even damage the spindle. Cutting edge chamfers are a common way to avoid such vibrations. In this paper it is shown experimentally and theoretically how such chamfers affect the process damping effect and hence the stability limit. A cutting force model is presented, that takes into account the process damping effect and the geometry of the chamfered cutting edge. Theoretically predicted stability charts are compared to experimental data. It is shown that due to cutting edge chamfers process damping is not restricted to the low cutting speed range anymore but also occurs at higher spindle speeds.