Influence of spatial position of double turntable swing on dynamic characteristics of five-axis machine tool

Abstract

In the machining of a five-axis machine tool with a double turntable, the dynamic characteristics of the machine tool are affected by different spatial positions of workpieces. Predicting the dynamic characteristics of machine tools at different spatial positions can effectively improve the machining accuracy of workpieces. In the present study, a five-axis CNC machine tool (Tuopu VMC-C50, China) is considered as the research object. Firstly, the bearing stiffness model of the double turntable rotary system is established, and the influence of the joint stiffness of the turntable bearing on the dynamic characteristics of the five-axis machine tool table rotary system is studied. Based on the established three-dimensional model and rigidity of the sliding joint surface of the machine tool, the machine tool modes at 81 working positions are analyzed. Accordingly, the influence of different swinging positions of the double turntable on the dynamic characteristics of the five-axis machine tool is studied. Finally, based on the three-dimensional Kriging prediction model, variations of the natural frequency and vibration amplitude of the system in the machining space for different swing table angles are analyzed.