Enhancing the Fidelity of Suspension Bath-based 3D Printing through Angled Needles

Suspension bath-based 3D printing has been increasingly applied in fabricating complex structures from challenging-to-process materials such as PDMS, liquid metal, and bioinks. However, this method still encounters difficulties in interlayer bonding and print-path optimization. Several studies have sought to address these challenges through various strategies. In this study, a novel strategy to improve print fidelity by utilizing the choice of printing needles with different extrusion angles (0°, 45°, and 90°) was proposed. We experimentally evaluated the impact of the needle angle on the structural integrity of printed objects, focusing on the permissible angle between needle movements and extrusion directions, as well as the influence on filament breakage and interlayer voids. Our findings reveal that using varied needle angles substantially reduces interlayer voids and enhances structural cohesion, offering a considerable enhancement over existing single-angle needle printing strategy. This research paves the way for advancing suspension bath-based 3D printing technologies.