Near‐Infrared Light‐Assisted Direct Ink Writing for Shape‐Following Printing of High‐Strength Composite Components

ABSTRACT Direct ink writing (DIW) 3D printing technology has attracted widespread interest due to its versatility in raw material selection, material utilization efficiency, and straightforward processing characteristics. Nevertheless, gravitational deformation and collapse issues of the extruded ink during DIW printing hinder its application in fabricating large or overhanging structures. In this study, the integration of near‐infrared (NIR) light and DIW technology was developed to achieve real‐time and in situ photopolymerization of the extruded ink. With such integration, the printed architecture can be stabilized, and the deformation induced by self‐weight can be mitigated. To further improve the mechanical integrity of the printed parts, short glass fibers were incorporated into the photocurable ink, promoting directional reinforcement during deposition. Compared to unreinforced photocurable resin, the tensile strength of printed samples containing 30 wt% glass fibers was increased by 19.10%, while the flexural strength improved by 18.47%. The printed structures exhibited high‐dimensional fidelity and mechanical robustness, highlighting the potential of NIR‐assisted DIW for fabricating sophisticated, large‐scale polymer composite components with enhanced mechanical performance.