A review of 3D printing continuous carbon fiber reinforced thermoplastic polymers: Materials, processes, performance enhancement, and failure analysis

Fused filament fabrication (FFF) technology, recognized as a leading 3D printing method for the production of continuous carbon fiber reinforced thermoplastic polymer (CCFRTP) components, has garnered significant attention due to its design flexibility, independence from molds, and capability for rapid prototyping of complex structures. This paper presents a comprehensive analysis and review of the challenges associated with enhancing mechanical properties stemming from interfacial bonding issues and pore defects in 3D-printed CCFRTP parts. Specifically, this study thoroughly examines the properties and modification techniques pertinent to two critical constituents of printing materials: the resin matrix and carbon fiber reinforcement. It also explores advancements in FFF printing equipment specifically designed for CCFRTP components, alongside current developments in related impregnation processes. Furthermore, this work introduces an evolution in continuum path planning grounded in principles of structural lightweight design while applying topology optimization to create anisotropic CCFRTP structures. The influence of various printing process parameters on mechanical properties is analyzed systematically; additionally, processing strategies that incorporate auxiliary reinforcement techniques—such as thermopressure, negative pressure, laser application, magnetic fields, microwave energy, and infrared radiation—are emphasized. The mechanical behavior is meticulously tracked throughout the study, while corresponding failure mechanisms are scrutinized through recent advancements in characterization methods aimed at visualizing void defects. We critically assess the existing technological challenges that impede the 3D printing of CCFRTPs and propose potential future research directions intended to inspire further exploration within this promising field. Highlights: Optimizing the CCFRTP interface hinges on material matching and synergistic CCF mods. CF continuity and anisotropy demand refined print/impregnation design and algorithm. Stress-guided path planning with topo optimization unveils innovative potential. Optimized print parameters and ancillary processes facilitate enhanced performance. 3D characterization ensures reliable material void and process defect assessment.