Fiber–matrix impregnation behavior during additive manufacturing of continuous carbon fiber reinforced polylactic acid composites

Continuous carbon fiber reinforced thermoplastic (C-CFRTP) composites have been broadly applied in key industries due to their excellent material properties. Fused filament fabrication (FFF), as a material extrusion additive manufacturing (AM) technology, can be applied to fabricate C-CFRTP parts with complex structures. However, the underlying fiber–matrix impregnation behavior during FFF of C-CFRTP composites, which is a key factor to bridge process parameters and mechanical properties, is still unknown. In this paper, we developed a theoretical model to discern the impregnation process at different parametric conditions. The microscopic measurement of continuous carbon fiber reinforced polylactic acid (PLA) specimens was conducted to characterize the impregnation percentage for the model verification. The results indicated that almost all predicted values agreed well with the experimental results. Additionally, the increase in impregnation percentage was found to improve the tensile strength. The findings in this work provide insights into the process-impregnation-property relationship and promote the effective FFF fabrication of C-CFRTP components.