Analysis and Prediction for Spindle Thermal Bending Deformations of a Vertical Milling Machine

To understand the thermal behavior of the spindle, the radial thermal drift errors (RTDEs) of the spindle are tested in this paper. To analyze the influence of environmental temperature to the RTDEs, the RTDEs are tested at 0 r/min. Afterward, the RTDEs of the spindle and the temperature values of key points are tested at different speeds. The thermal deformation process of the spindle is analyzed and verified by thermal imaging testing. The RTDE models of ten thermal deformations are established. Also, the relationship between compensation value and tool length, determination criterion of thermal deformations, algorithm flow, and parameter identification process are presented by using an inverse model. The compensation effects are verified using both simulation and experimental data. The results indicate that high accuracy can be achieved for all rotating speeds, with parameters identified using data of one speed. The strong robustness of the proposed model is proved.