Internal cooling channel topology optimization in milling tools using CFD

Internally cooled milling tools deliver high-pressure cutting fluid directly to the tool-chip interface through internal channels and have been proven effective in mitigating the excessive heat generated when machining titanium alloys. However, conventional channel designs often suffer from poor surface smoothness and high flow resistance, which limit cooling efficiency. To address this, topology optimization combined with computational fluid dynamics (CFD) simulation is applied to minimize flow pressure drop and to improve the cooling performance of the milling tool in this study. CFD is employed to model the flow behavior of cutting fluid inside channels, and the volume of fluid (VOF) multiphase flow model is introduced to simulate the jetting process. The tool body is fabricated using selective laser melting (SLM) followed by mechanical post-processing. Milling tests are conducted on TC18 titanium alloy. CFD simulations and experimental results show that the optimized design reduces pressure drop within channels by 53.13%. Across various cutting parameters, cutting temperatures are reduced by 8.34% to 12.15%. Significant improvements are observed in surface roughness, tool wear, and chip morphology. The simulation and experimental trends are in good agreement, with notable improvements in outlet flow rate and velocity. These results validate topology-optimized internal channels as an effective strategy for enhancing milling tool cooling performance.