Modeling of kinematics errors and alignment method of a swing arm ultra-precision diamond turning machine

Ultra-precision machining has been widely used in the manufacturing of optical components. Volumetric error analysis and error compensation are essential issues that must be considered to improve the accuracy of the machining process. However, analysis of the effects of kinematics errors on surface generation by ultra-precision machining using a swing arm ultra-precision diamond turning machine (SA-UDTM) and the alignment methods required have received little research attention to date. This paper presents the development of a kinematics error model of the SA-UDTM that accounts for geometric errors by simplifying the machining system and considering it as a rigid multi-body system. Then, the main error contributions to the processing precision can be derived from sensitivity analysis of error components. Finally, an alignment method is developed to reduce or eliminate the corresponding positioning errors of the mechanical system and thus improves the form accuracy of processed surface. To verify the theoretical kinematics model and the proposed alignment method, a series of contrast machining experiments have been performed, and the experimental results indicate that the proposed method is effective.