Identification of modal parameters of machine tools during cutting by operational modal analysis

The dynamic behaviour of machine tools differs between standstill and process state. Operational modal analysis (OMA) makes possible to identify modal parameter under process conditions. In this paper, it is shown, how far the assumption of a time-invariant behaviour as well as abroad band excitation can be fulfilled by exciting the machine with a cutting process. After describing the dynamic behaviour in the work space to determine a time-invariant tool path, a broadband excitation is generated by changing cutting parameters during milling. The modal parameters are identified by different OMA methods and compared to results of the experimental modal analysis.