Remanufacturing of recycled carbon fiber-reinforced composites based on fused deposition modeling processes

Recycled carbon fiber (RCF) can be used in fused deposition modeling (FDM), which can not only improve the reuse value of carbon fiber but also make up for the insufficient performance of general FDM products. According to the recycling principle, the device special for carbon fiber-reinforced resin matrix composite (CFRP) recycling is developed; soft and fluffy carbon fibers were obtained under the optimal process parameters in this work. RCF was remanufactured into composites by grinding, extrusion, and FDM. The microtopography and monofilament tensile strength of RCF were analyzed, the particle size distribution of chopped RCF and the interface combination in composites were observed, and the mechanical properties of RCF-reinforced polylactic acid (PLA) composites (RCF/PLA) were studied. Results show that the monofilament tensile strength of RCF obtained under the optimal process parameters was 8% higher than that of original carbon fiber (OCF). Compared with PLA, the tensile strength of OCF-reinforced PLA composites (OCF/PLA) and RCF/PLA composites was reduced by 25% and 12.5%, respectively. The chemical bonding between RCF and resin matrix and the nozzle temperature, layer height, and printing speed in FDM process have an important influence on the tensile strength of the composites. Compared with that of PLA, the bending strength of OCF/PLA composites increased by about 7.8%, the flexural modulus increased by about 81%, the bending strength of RCF/PLA composites increased by 10.4%, and the flexural modulus increased by 87%. Through FDM, RCF can be used to enhance the resin matrix with higher requirements for stiffness, bending strength, and wear resistance.