Innovative design methods for the geometric accuracy of machine tool guide rail oriented to spatial accuracy

Abstract

The design of geometric accuracy in machine tools is crucial for enhancing machining precision. This study introduces geometric accuracy design methods that are oriented to spatial accuracy to guide the assembly of machine tool guide rails. Firstly, based on screw theory, a spatial error model for the machine tool is constructed, elucidating the relationship between spatial error and geometric error. Secondly, an error transmission model linking the guide rail installation error with the geometric error of moving parts is established, predicated on the rigid body hypothesis. This model reveals the mechanism of the error homogenisation in the machine tool feed system. Then, novel geometric accuracy design methods oriented to spatial accuracy are proposed catering to both non-morphological and morphological design requirements. Finally, the effectiveness and universality of the design methods are verified by simulations and experiments. The results show that more than 95.62 % of the machine tool workspace simulation points are less than 15 μm in spatial accuracy, and the design results outperform the experimental results by 2.05 μm in terms of the body diagonal spatial error.