An RSM-NSWOA-Based Method for Optimising Structural Parameters of Electric Spindle Cooling Water Jackets

Abstract As the critical transmission element in high-precision machining centers, high-speed electric spindles feature compact designs and excellent sealing; however, they are susceptible to thermal accumulation during operation due to insufficient heat dissipation. To mitigate excessive stator temperatures in 210-type electric spindles operating at 4000 r/min while overcoming the manufacturing complexity of conventional cooling water jackets, this study proposes an RSM-NSWOA-based structural optimization method for cooling water jackets. The critical design variables selected for optimization were primary tooth width (WB), secondary tooth width (WS), and trapezoidal tooth count (CN). A response surface model was developed to establish predictive equations for spindle temperature and thermal uniformity, enabling multi-parameter optimization. Optimization results demonstrate enhanced cooling performance at WB = 7.87, WS = 4.06, and CN = 41. Experimental validation confirmed a maximum temperature reduction of 4.5°C and thermal displacement reduction of 1.85 μm in the optimized motorized spindle, directly enhancing thermal stability and machining precision. Under maximum-speed operation, the spindle temperature consistently decreased, validating the robustness and practical utility of the RSM-NSWOA framework.