Analysis for Influences of Joints on Dynamic Characteristics of Precision Machine Tools

To investigate the influence mechanism and effects of joints on the dynamic characteristics of an entire machine tool, an accurate equivalent dynamic analysis model for joints was constructed by using ANSYS simulation software based on a multi-objective genetic optimization method. Subsequently, an accurate dynamic model of the entire machine tool was established, and the modal testing of the entire machine tool was completed. The testing results show that the errors between the calculated natural frequencies of the first six modes from the entire machine tool and the experimental data are less than 5%, verifying the effectiveness and accuracy of the analysis model. Based on this dynamic model, a comparative analysis was conducted to examine the relationships among movable joints, screw joints, foundation joints, and the dynamic characteristics of the machine tools. The analysis results indicate that movable joints have the greatest influence on the 4th, 5th and 6th order natural frequencies of the entire machine tools, followed by foundation joints, with screw joints having the least influences. Additionally, foundation joints are identified as the primary factors affecting the whole-body modal shapes of the machine tools, while screw joints and movable joints have relatively minor effects on the modal shapes.