Abstract: Volumetric error modelling and compensation has become one of the most cost-effective ways to improve the accuracy and performance of machine tools. However, the time-consuming measurement process limits its application. Hence, a volumetric error rapid modelling and compensation method based on the sensitivity analysis is proposed. Firstly, a generalized kinematic model of the vertical machining center is established. Then the most important key error components are determined according to the sensitivity analysis of the all error components, while the less important angular errors can be neglected. Consequently, all key error components are measured and modelled with Chebyshev polynomials, and further applied in a real time error compensation system. To evaluate the effectiveness of this method, the positioning errors alone each translational axis and body diagonal lines with and without error compensation are compared. The former is greatly reduced from 21.9 μm to 6.5 μm, while volumetric error similarly reduced from 81.6 μm to 35.5 μm. Finally, this method is applied into 20 vertical machining centers, all improved to less than 40 μm. This paper innovatively uses sensitivity analysis as the theoretical basis for simplifying machine tool error models, and proposes a rapid modeling and compensation method for batch of vertical machining centers. This method can effectively improve the error compensation efficiency, which shows great potential in the future industrial applications.

Key words: volumetric error, sensitivity analysis, body diagonal error evaluation, batch of CNC machining centers, real-time error compensation