Abstract: In view of the frequency response characteristic of small stiffness and dynamic variation and the dynamic behaviour of high order for high-speed milling system of thin walled structures, stability limits prediction theory is studied. In connection with the small-stiffness frequency response characteristics of thin walled structures, the dynamic model and the stability critical condition determined by the relative dynamic behaviour between tool subsystem and workpiece subsystem are put forward. In the light of the high-rotation characteristics of high-speed milling, the stability limit prediction model based on the high-order dynamic behaviour of multi-DOF system is built. In view of the time variability of thin walled structures’ dynamic behaviour during the machining process, the method to predict the stability limit by tracing the dynamic behaviour variation of workpiece during diverse machining stages is suggested. The stability prediction model and method proposed are validated by the experiments carried out to cut the typical thin walled structures.

Key words: Dynamic behaviour, High-speed milling, Stability prediction, Thin walled structures