Axial Offset Error Modeling of Big-Plus Bottle Grip Taper Tool Holder Using Natural Neighbor Interpolation on Spindle Speed Domain

The precision of machine tools is crucial for ensuring the accuracy of final products, directly impacting manufacturing quality and efficiency. Axial offset error, a significant factor in tool holder-spindle interfaces, mainly affects high-speed machining processes. In previous research, the axial offset error of the taper contacts BT40 tool holder was modeled by linear interpolation of the maximum and the residual error polynomial curves of maximum spindle speed. This study aims to develop a more accurate axial offset error modeling using the natural neighbor interpolations of the measured errors in the spindle speed domain. Experiments were conducted on BT40 and BBT40-type tool holders, and the key findings are as follows. The maximum axial offset error for the BT40 tool holder was 7.95 μm at 10,000 rpm, with a residual error of 4.45 μm. The maximum error for the BBT40 tool holder was 3.80 μm at 12,000 rpm, with errors decreasing and becoming negative at higher speeds, reaching −5.36 μm at 20,000 rpm. The new model reduced the prediction accuracy by 43% compared to the previous model, demonstrating improved robustness against various error tendencies. The proposed model enhances prediction accuracy and offers potential applications in offline simulation and real-time error compensation, contributing to higher manufacturing quality without requiring hardware changes.