Diagnosis of self-excited vibrations in the machine tool – cutting process system

The work examines the principal problems associated with the diagnosis of self-excited vibrations that frequently develop when cutting materials on machine tools. Heavy vibration (chatter) has a detrimental influence on the machining results, the tool and the tooling. Therefore, it is important to take appropriate countermeasures not only at the stage of the machine tool designing but also at the cutting process planning and the machine operation. First, methods and procedures proposed for locating weak points in the machine tool structure responsible for the chatter development are presented. Then, a number of different methods for on-line chatter detection are tested. Their efficiencies are evaluated and compared. Some remarks on the choice of sensors and their placement on the machine are given. Several examples of self-excited vibration signals stored during unstable milling and the results of their analysis are shown. The directions of future investigations are outlined.