Design, manufacturing, and characteristics of steel–CF/PEEK hybrid shaft with optimized thermal structure

Thermal deformation is one of the primary sources of errors, reducing the overall accuracy of precision CNC machine tools. For instance, it makes improving the machining accuracy of traditional steel machining shafts difficult. To reduce thermal deformation in machine tool shafts, this study proposed a method to design a steel–carbon fiber-reinforced plastic (CFRP) hybrid shaft by integrating steel with carbon fiber/polyetheretherketone (CF/PEEK). The proportions and arrangements of CF/PEEK within the shaft were optimized using the rule of mixtures. To further enhance the heat dissipation capability of the shaft, a multistep structure was designed based on the thermal characteristics and arrangements of the CF/PEEK. The internal heat flow direction of the hybrid shaft was analyzed. The heat transfer theory was applied to the results to derive and verify the thermal structure optimization design method. Subsequently, a hybrid shaft prototype was manufactured using a laser-assisted in situ consolidation process. The thermal deformation and dynamic characteristics were investigated. The results demonstrated significant reductions of 55.2% and 46.7% in both the axial and radial thermal deformations compared with the steel shaft, respectively. This study provides an effective structural design and manufacturing approach for the thermal deformation control of machine tool shafts, potentially improving machining accuracy and performance.