Fabrication strategy for joints in 3D printed continuous fiber reinforced composite lattice structures

Three-dimensional (3D) printing has revolutionized the fabrication process of continuous fiber reinforced composite lattice structures (CFRCLSs) with complex designs. However, optimal strategies for fabricating specific features of lattice structures, particularly joints, are not established, limiting the fabricated parts' geometry accuracy and mechanical property. To address the above issues, we propose an interlayer-based adaptive process planning strategy for printing joints of CFRCLSs. More specifically, six strategies with different printing paths and parameter settings were used to fabricate an orthogrid structure. Their mechanical properties were compared and the part fabricated with the proposed strategy outstands the others. In addition, the failure modes and internal microstructure at the joints were analyzed using the digital image correlation (DIC) and micro-CT techniques for providing deep insights. Results indicate that the proposed strategy can significantly improve the geometry accuracy and mechanical properties of fabricated parts. Moreover, the effectiveness of the proposed joint strategy has been validated with two representative metamaterial designs, i.e., horseshoe and auxetic structures.