Enhancing Z‐direction strength of 3D‐printed polylactide by embedding continuous carbon fibers

Abstract A significant challenge in the deployment of 3D‐printed polylactide (PLA) parts is their inadequate interlayer strength. To address this issue, a novel methodology for the fabrication of fused deposition modeling (FDM) components with continuous carbon fibers aligned in the building direction has been developed. This approach involves embedding continuous carbon fibers into the print path through mechanical traction, enabling the fabrication of complex‐shaped reinforcements. Tensile testing revealed that the incorporation of carbon fibers at a volume fraction of 5.8% significantly enhanced the Z‐direction strength of the specimens by 449%. Furthermore, the maximum fracture strain observed was 1611.7% greater than that of the control group, and the elastic modulus increased to 381% of its original value. The study also investigated the mechanism of enhancement and fracture, observing transitions from brittle to ductile fracture with increasing fiber content. The proposed method was demonstrated through the fabrication of a continuous fiber‐reinforced butterfly arch bridge model specimen, which exhibited a 120.5% increase in load‐bearing capacity compared to the unreinforced specimen in three‐point bending tests. This methodology offers a promising solution for enhancing the Z‐direction strength of 3D‐printed PLA components, enabling their application in load‐bearing structures. Highlights Employing continuous fiber to enhance FDM Z‐direction strength. Tensile strength, maximum fracture strain, and elastic modulus in the Z‐direction increased by 449%, 1611.7%, and 381%, respectively. Increasing Z‐direction fiber content induces a transition from brittle interlayer bond failure to ductile tearing. The fiber‐reinforced butterfly arch bridge model specimen demonstrated the potential for reinforcing complex shapes.