Continuous fibre composite 3D printing with pultruded carbon/PA6 commingled fibres: Processing and mechanical properties

Continuous Fibre composite 3D printing (CF-3DP) technology is a newly developed Additive Manufacturing (AM) process. By employing continuous fibre as a reinforcement for the composite, the mechanical properties of the 3D printed part can be significantly improved. However, owing to the process's early stage of development, the mechanical performance of the printed material is still unable to compete with composites produced using conventional manufacturing processes. This can manly be attributed to lower fibre volume fractions and/or higher void content. The grand objective of the research project is to establish a demonstrator of practical applications, and in this paper, preparatory developments were carried out to pave the ground for the subsequent developments, including feedstock materials development, printing process development, and materials properties evaluation. Efforts has been made to increase fibre volume fracture, to reduce voids contents, to evaluate effective properties systematically. The static mechanical test results showed relatively good longitudinal tensile properties while matrix sensitive properties were low, as to be expected in UD composites with a relatively weak matrix material. The advantage of CF-3DP is to achieve fibre steering, and the steered fibre design can be achieved by the current process to realize novel composite structures in future study.