The thermal drift modeling of spindle system based on a physical driven deformation methodology

Thermal error is one of the main factors that leads to the decline of CNC machine tool’s accuracy stability. The location of the typical thermal key points was determined by the finite element analysis model of the spindle system. The thermal experiments were conducted on a spindle of the milling machine tool. Furthermore, the distribution law of the spindle temperature field and the mechanism of its deformation were elaborated. On this basis, the temperature field model of each region of a spindle system was established based on the generation, conduction, and convection theory of heat, spindle speed, and motor load. A physical driven deformation modeling (PDDM) method was put forward for building the relationship between the axial thermal drift error and the temperatures of the key points of the spindle system. Then, with parameters identified using data of one speed, the influence of structural size uncertainty on prediction results was analyzed by the first-order second-moment (FOSM) method. The prediction residual errors of the suggested model with multiple size parameter fluctuation were provided. Finally, the effectiveness and robustness of the time-varying error model were verified by experiment and compensation.