Compensation for the thermal error of a multi-axis machining center

This paper presents a systematic methodology for the thermal-error correction of a machine tool. The generalized geometric error model of a multi-axis machine is derived to describe the error motion between the cutting tool and the workpiece using the homogeneous transformation matrix. The thermal deformation is modeled using grey system theory so that a dynamic model can be obtained. An off-line method and an on-line method are proposed to use the grey system model to predict and compensate for the thermal error. This method can significantly reduce the number of sensors used in temperature monitoring during the compensation process. The effectiveness of this method is tested by simulations and by experiments. The proposed methodologies can be used to improve the manufacturing accuracy of the modern manufacturing system in a cost effective way. (C) 1998 Elsevier Science S.A.