Initial-solution-guided topology optimization of high-performance cooling structures for thermal-error control in precision coordinate boring machine tools

Thermal deformation in feed drive systems is a primary source of positioning inaccuracy and machining error in precision coordinate boring machine tools. In particular, friction heat generated at the ball screw-nut interface and bearing assemblies leads to axial thermal elongation and long-term accuracy degradation. To address the above challenges, a feed-system-oriented thermal control strategy is proposed based on an initial-solution-guided topology optimization framework. A topology-optimized cooling jacket is designed and conformally integrated around the nut region to dissipate heat locally and suppress axial thermal propagation along the screw shaft. Parameterized initial configurations are introduced to guide the topology optimization process toward physically meaningful and manufacturable flow networks. The numerical simulations and experimental tests demonstrate that the optimized cooling structures achieve a superior balance between heat dissipation efficiency and hydraulic resistance. At a Reynolds number of 6000, the heat-source surface temperature is reduced by 12–15%, while the pressure drop decreases by 18–20%, accompanied by significantly improved temperature uniformity. More importantly, the enhanced thermal regulation directly improves feed drive system motion accuracy. System-level experiments conducted on a full-scale precision coordinate boring machine show that axial thermal elongation is reduced from 0.77 mm to 0.31 mm. The positioning error and repeat positioning error of the feed drive systems are suppressed by approximately 80–90% and 85–90%, respectively. Machining experiments further confirm that the stabilized thermal behavior leads to improved machining accuracy, reducing the measured geometric deviation from ±20 μm to ±5 μm. The results demonstrate that initial-solution-guided topology optimization provides an effective and scalable approach for feed drive system thermal-error control and machining accuracy enhancement in precision machine tools.