Analysis of factors affecting the straightness of assembled guide rails based on the dispersion of preload force

Abstract Guide rails are the core components of the linear feed system of machine tools, and their assembly accuracy directly affects the precision retention of machine tools during subsequent service. In the assembly method using bolt group connections, the dispersion of bolt preload is a key factor influencing the geometric accuracy of the guide rail surfaces. Therefore, to investigate how changes in various influencing factors ultimately affect the straightness error of guide rails by altering preload dispersion, this study established an accurate finite element model of guide rail assembly and systematically analyzed the operating mechanisms of three key factors: torque magnitude, number of torque loadings, and the friction state of the contact surface. The results show that the aforementioned factors exert a significant influence on the straightness of the guide rail surfaces by changing the dispersion of bolt preload. This research provides effective guidance for optimizing the assembly process of high-precision guide rails.