An Improved Method for Straightness Error Modeling and Compensation in CNC Machining Center

Abstract

Straightness error is one of the main factors which affect the machining accuracy in CNC machine tools. To improve the modeling accuracy and efficiency for straightness error, a new modeling method is proposed based on the Least-square fitting of orthogonal polynomials in this paper. Using this error modeling method, the maximum straightness error is fitted by 95.8%. The fitting accuracy of cubic polynomial established by the proposed error modeling method is better than the fitting accuracy of quartic polynomial established by Matlab. To realize the real-time compensation for straightness error, a network and external coordinate offset based error compensation method is proposed in this paper. Experiments results show that the maximum straightness error of the machining center is compensated by 89.6% compared with no compensation.