Modeling and analysis of straightness evolution mechanism of ball linear guides based on heat-force coupling

In the service process of high-speed precision CNC (Computer Numerical Control) machine tools, the heat-force coupling deformation of ball linear guides is a core factor affecting machining accuracy. Existing research focuses on the influence of a single heat source or static load, and lacks systematic modeling of the dynamic evolution mechanism of straightness under multi-field coupling. For this reason, this paper proposes a straightness evolution prediction method based on geometric-thermal-force multi-field coupling. Firstly, we establish a transfer model of the internal contact deformation of the slider and the initial geometric deviation of the guideway, and analyze the induced mechanism of the preload force distribution on the initial deformation of the slider. Secondly, the heat-force coupling constitutive equation of internal and external thermal interaction is constructed to quantify the dynamic coupling effect of temperature field and stress field. And we propose a method for predicting the evolution of guideway straightness during service to realize the quantitative assessment and analysis of the stability of motion linear axis precision. Finally, by comparing the test and simulation, the error rate between the established model and the measured value is less than 7.03%. This study provides effective theoretical and methodological support for the dynamic thermal stability control of high-precision guideway.