On the chatter frequencies of milling processes with runout

The detection of undesirable vibrations in milling operations is an important task for the manufacturing engineer. While monitoring the frequency spectra is usually an efficient approach for chatter detection, since these spectra typically have a clear and systematic structure, we show in this paper that the stability of the cutting process cannot always be determined from solely viewing the frequency spectra. Specifically, the disturbing effect of the tool runout can sometimes prevent the proper determination of stability. In this paper, we show these cases can be classified by alternative analysis of the vibration signal and the corresponding Poincaré section. Floquet theory for periodic systems is used to explore the influence of runout on the structure of milling chatter frequencies. Finally, the results from theoretical analysis are confirmed by a series of experimental cutting tests.