Abstract: In order to predict the machining precision of the machine tool and validate its design concept, the geometric errors of a precise vertical machining center were analyzed, and its precision prediction model was established based on the multi-body system theory. The correlations among the multi-bodies were described with the topology structure and the low-order body array. The coordinate transformation relationships between multi-bodies were described based on the homogeneous transformation matrix. The characteristic matrix and the relative motion equations of the motions between 2 arbitrary adjacent objects of the multi-body system were derived. A precision prediction model was built for the precise vertical machining center. Based on the simulated machining of a typical workpiece, the precision prediction of the machine tool was realized. The results showed that the proposed precision model can describe the systemic structure of the vertical machining center effectively and abstractively, predict the machining precision reasonably, provide a basis for the improvement of the machine tool design concept and the precision deployment.

Key words: mechanical design, precision design, multi-body system, precision modeling, accuracy prediction