A stability analysis of single-point machining with varying spindle speed

Abstract The rate at which metal can be removed by a machine tool is often limited by the onset of an instability commonly called ‘chatter’. It has been suggested that greater widths of cut could be achieved without chatter on a given machine by modulating the spindle speed continuously. A stability analysis is presented which gives, for any mean spindle rotation speed and degree of modulation, the limiting width of cut for chatter-free cutting. The machine tool is represented by a simple mass/spring/damper system, only the case of a single cutter is considered; however, extension of the analysis to more complex models is straightforward. The analysis indicates that a modest increase in useable width of cut is given by using spindle speed modulation. Results are compared with corresponding results obtained from an analogue computer simulation of the machine tool/cutter system.