Modeling and compensation for spindle's radial thermal drift error on a vertical machining center

• Spindle's radial thermal drift error model of different thermal postures for a vertical machining center was established.
• Special values were chosen for judging the spindle's real-time posture and the compensation strategy was developed.
• The calculation of geometric parameters on the prediction of results was carried out.
• Simulation and experiment results were demonstrated to verify the correctness of our models.

In the present work, spindle's radial thermal drift error (RTDE) was studied on a vertical machining center. RTDEs in X-direction and Y-direction of a vertical machining center were tested and the main direction of RTDE was determined as Y-direction. RTDEs in Y-direction and temperatures in key points of spindle were tested using different rotating speeds. RTDE models under different postures were established and the compensation strategy was presented. Thereafter, the influence of geometric parameters on the prediction of results was obtained using advanced first order second moment method. The compensation effects were verified using both simulation and experiment. The results indicated that high accuracy and strong robustness can be achieved with the proposed model, even if the rotating speed of spindle randomly changed, or the spindle was disturbed by the cooling system.