A woven-like toolpath strategy for translaminar reinforcement in continuous fiber reinforced polymer additive manufacturing

Improving the mechanical performance of material-extrusion-based additive manufacturing has long been recognized as a major challenge in the field. The introduction of continuous fibers substantially improves the in-plane strength of printed parts; however, the inherently weak interlayer bonding remains a critical bottleneck that restricts their practical application. Inspired by three-dimensional woven composites, this study proposes a woven-like toolpath strategy for continuous fiber reinforced polymer additive manufacturing (CFRP-AM), in which continuous fibers periodically interlace across adjacent layers to construct a global translaminar interlocking architecture and thereby enhance interlayer strength. Compared with planar toolpaths, the woven-like toolpath achieves substantial interlaminar performance enhancement without compromising in-plane strength, increasing interlayer tensile strength by 97.37% and interlayer shear strength by 126.96%. Fracture analyses using optical microstructural characterization techniques reveal that woven-like toolpaths fundamentally alter crack propagation, from flat interlayer delamination in planar specimens to multi-layer crack deflection and extensive fiber breakage in woven-like toolpath specimens, and significantly increase fracture energy. This woven-like toolpath strategy provides a simple yet effective route to enhancing interlayer performance of CFRP-AM, achieving substantial strengthening without requiring any auxiliary heat source, external field, or hardware modification. At the same time, the method is fully compatible with existing thermal, material, or field-assisted enhancement techniques, enabling synergistic improvements and offering broad potential for high-performance additive manufacturing.