Continuous carbon fiber reinforced filaments manufactured by a cost-effective and two-step impregnation approach

Fused filament fabrication (FFF) based 3D printing of continuous carbon fiber-reinforced thermoplastic composites (C-CFRTP) has emerged as a new manufacturing method and offered new avenues for the design and fabrication of complex composite structures. To ensure printing quality and improve mechanical performance of composites, the prevailing approach is producing pre-impregnated filaments before 3D printing. However, current manufacturing methods of filaments still rely on traditional pultrusion approaches, necessitating high facility investment and resulting in elevated prices. Here, we propose a low-cost C-CFRTP filament manufacturing method utilizing a two-step impregnation process. To ensure high filament quality while maintaining compactness, we introduce a liquid-solid two-step impregnation method aimed at flattening carbon fiber bundles during impregnation to achieve thorough and uniform infiltration. We successfully fabricated carbon fiber reinforced polyamide (PA) prepreg filaments and analysed its impregnation and mechanical properties. This study holds significant implications for enhancing impregnation efficiency and reducing the cost of C-CFRTP