Abstract The geometric error of a three-axis vertical machining center is a critical technical indicator for evaluating its machining accuracy, and the precision of error identification plays a decisive role in the engineering effectiveness of compensation strategies. Based on the multibody system topology theory and the Denavit-Hartenberg matrix theory, this study establishes a contribution transfer model to quantify the impact of multi-axis geometric error on the positional errors at the end-effector of the three-axis vertical machining center. Experiments were performed on a VMC650 three-axis vertical machining center platform, where 21 geometric error items were precisely measured using a Renishaw XM-60 laser interferometer. An error spatial distribution function was constructed through polynomial regression analysis, and the optimal fitting coefficients of polynomial basis function combinations were solved to provide an analytical mathematical description for error prediction at arbitrary spatial positions. Based on the geometric error model, this study innovatively combines Monte Carlo sampling with principal component analysis to perform sensitivity analysis on geometric error parameters and analyze the transmission of geometric error under small disturbances, thereby effectively identifying key sensitive geometric error parameters. The research results offer theoretical guidance for structural optimization design and compensation parameter calibration of three-axis vertical machining centers, significantly enhancing their comprehensive machining accuracy.
Zheng et al. (Tue,) studied this question.