Additive manufacturing of high-strength polyamide 6 composites reinforced with continuous carbon fiber prepreg

The additive manufacturing of continuous fiber reinforced thermoplastics (CFRTPs) paves way for the high-strength, light-weight components for variety of load-bearing applications. In this work, the continuous carbon fiber reinforced PA6 (CCF-PA6) composites was successfully printed from the prepreg filament. The prepreg filament was prepared in-house by impregnating the heat-and-acid treated 1 K carbon fiber bundle with the molten PA6. The tensile strength of the prepreg filament, which contained with 40 vol% CF, reached 984 MPa. The unidirectional CCF-PA6 specimens were subsequently 3D-printed with the prepreg filament, and the mechanical strength of those 3D-printed specimens were tunable by adjusting a set of printing parameters, such as layer thickness, hatch spacing and printing temperatures. The highest tensile strength of the specimen reached 555 MPa. Those specimens also exhibited outstanding mechanical strength at elevated temperatures, still reaching 184 MPa at 150°C. The mechanical strength of those specimens was dependent on the content of the fiber. This study can hopefully provide new insights for feedstock design and spur novel ideas in tailoring the mechanical properties of the 3D-printed CFRTPs.