Stability analysis in milling of flexible parts based on operational modal analysis

The classic approach to stability analysis in milling is based on the frequency response function (FRF) of the system obtained by the impact test. Application of this technique for a flexible workpiece with variable dynamics such as thin-walled structures may be difficult or impossible because the modal parameters of a part change due to material removal or tool position. Besides the workpiece vibration are significant compared to that of the tool. Therefore precise determination of the varying FRF is vital. It can be achieved by application of operational modal analysis based on workpiece acceleration measured during machining. The novelty of the proposed procedure lies in using the cutting force model for scaling modal residues that enables constructing stability lobes diagram from output-only data. (C) 2014 CIRP.