Nozzle-assisted Continuous Additive Manufacturing of Mesoscale Multimaterial Structures

Abstract Photopolymerization-based additive manufacturing (PAM) has emerged as a powerful technique for fabricating complex three-dimensional (3D) structures with high precision and resolution. However, current methods face challenges related to several manufacturing constraints. In particular, PAM often faces mass transport limitations that restrict resin replenishment between cured layers, leading to prolonged printing times and potential defects during large-area fabrication. Meanwhile, the separation forces generated during the formation of wide solid cross-sections frequently induce delamination or incomplete printing, further constraining scalability. To address these limitations, this study presents a novel Nozzle-Assisted Continuous Printing (NCP), which combines nozzle-driven material deposition with continuous photopolymerization to accelerate resin refilling, thereby enabling the fabrication of parts with wide cross-sections without compromising the printing speed and surface quality. The underlying printing mechanism is investigated through computational modeling and experimental validation, and the process capabilities are demonstrated via the fabrication of diverse mesoscale 3D models featuring solid, hollow, and complex cross-sectional geometries. Systematic evaluation of printing speed, surface finish, and dimensional accuracy confirms that NCP-printed parts exhibit superior mechanical integrity and reduced build times compared to conventional layer-by-layer techniques. Moreover, the NCP platform enables single step multimaterial fabrication, integrating distinct materials volumetrically and on the surface within a continuous process, thereby eliminating the need for additional hardware. Overall, these findings establish NCP as a versatile and scalable AM platform for the rapid manufacturing of high-quality mesoscale multimaterial components, with broad applicability in aerospace, biomedical, and mechanical engineering.