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The Dynamic Modeling and Vibration Analysis of the Large-Scale Thread Whirling System Under High-Speed Hard Cutting

□ This research took the large-scale thread whirling system as the object, to study the effect of supporting and holding way on the dynamic response of the workpiece system. Considering the specialties of large-scale thread whirling system and high-speed hard cutting technology, the theoretical dynamic model of the workpiece system was set up based on the Generalized Polynomial Assumed Mode Method after simulating cutting force by Deform 3D. Then, the natural frequency and the dynamic response characteristic were analyzed through solving the dynamic model with the Runge–Kutta method; the effect of hold devices as well as cutting position on the natural frequency of workpiece system were studied; and the vibration suppression capability of system damping and holding stiffness were also discussed. In the end, the large-scale thread whirling experiment was carried out to study the relationships between holding parameter, vibration amplitude and roughness. The results show that floating rests, holding stiffness and system damping play important roles in the vibration suppression during thread whirling process, and it is appropriate to set the holding ratio between 40% and 50% or between 65% and 70% in this case to improve machining quality.