In order to construct the high precision error compersation model,the topological relationship of machine kinematics was simplified and 59 independent error components were analyzed.Based on the rigid body kinematics with small error assumption,a new comprehensive error model with geometric error and thermal error was given.A new thermal error measurement method was proposed based on the thermal error analysis. Five-point method was used to measure the spindle thermal error. Six-point method was used to measure the feed axis thermal error.Considering error measurement point discrete and incomplete,with the variable weights GM(1,n),the thermal error model was proposed to pradict grey thermal error data.The experimental results showed that the spindle model error range was between 0~2 μm,and the feed axis model error range was between 0~12 μm. Theoretical prediction curves were consistent with the experimental results. A CNC real-time compensation software was developed with SIMEMS840D controller’s PMC program based on above error model. After the compensation, the machine tool error range was between 0~29 μm.
