Performance enhancement of 3D-printed carbon fiber-reinforced nylon 6 composites

The inherent defects of the layer-by-layer manufacturing process limit the mechanical performance of 3D-printed composite parts. This paper explores a process optimization method for continuous fiber composites 3D printing to improve the mechanical performance of 3D-printed CF/PA6 (Carbon Fiber/Nylon 6) parts. First, the effects of printing temperature, printing speed, layer thickness, and side step on the mechanical performance of 3D-printed CF/PA6 were studied by conducting variable parameter printing experiments. All optimal printing parameters for CF/PA6 were obtained, and their impact mechanisms were analyzed. Second, the coupling effect of temperature and pressure of post-processing reduced the internal voids of 3D-printed CF/PA6 and improved its mechanical properties. The influence mechanism of the coupling effect of temperature and pressure was summarized, and the optimal post-processing parameters applicable to CF/PA6 were obtained. Based on the above process optimization, the fiber volume content of the printed CF/PA6 reached 41.05%, and the bending strength and elastic modulus reached 651.54 MPa and 79.08 GPa, which were 209.05% and 179.53% higher than those before optimization. Moreover, the tensile strength and elastic modulus reached 730 MPa and 29.23GPa, which were 98.10% and 81.10% higher than those before optimization. The experimental results give a positive validation of the effectiveness and feasibility of the proposed methodology.