Research on chatter vibration suppression strategy of titanium alloy integral impeller milling based on process damping effect

Titanium alloy Ti-6Al-4 V, as a large-scale material used in the manufacture of aero-engine impeller blades, the chattering characteristics in milling machining have been a key challenge in restricting the improvement of machining quality and efficiency. In this paper, for the similar features of the dynamic characteristics of the tool subsystem and the workpiece subsystem in the blade milling system, a three-dimensional dynamics model of the dual-flexible system is established, and the determination of the key parameters in the model is accomplished through the calculation of the dynamic chip thickness as well as the modal parameter identification hammering experiments. The state transfer matrix of this model is constructed using the full discretization method, and the stability prediction of the system is realized according to Floquet theory. On this basis, the formation conditions of the process damping effect and the mechanism of suppressing the regenerative chattering are further deduced, and finally the stability prediction model integrating the process damping effect is established. The research results show that: the blade is most prone to chattering phenomenon at the upper edge position of the pressure surface during the finishing milling stage; the process damping effect can effectively suppress chattering and improve the system stability limit, and the process damping has a more obvious suppression effect in the low-speed region. Stability prediction models that take into account process damping effects have better prediction accuracy than conventional models.