Support-Free Additive Manufacturing via Multi-Axis Digital Light Processing

Digital Light Processing (DLP) 3D printing offers superior resolution and manufacturing speed but has traditionally relied on sacrificial support structures for complex geometries, leading to material waste and labor-intensive post-processing. This research presents a comprehensive framework for support-free additive manufacturing via a robotic multi-axis DLP system. By dynamically reorienting the build platform to align the object’s overhangs direction with the gravity vector, the system effectively mitigates the formation of auxiliary support structures for overhangs. However, this approach introduces significant challenges regarding non-planar layer generation with the corresponding light projection algorithm. To address these challenges, a modified slicing algorithm adapted from the open-source slicing algorithm is introduced. A novel variable layer thickness control strategy is implemented, utilizing pixel-level grayscale modulation to achieve precise layer curing depths required for non-planar slicing interfaces. Furthermore, a collision-free path planning algorithm is developed to navigate the submerged build environment, ensuring safe entry and exit trajectories while compensating for robot position repeatability errors. This work bridges the gap between multi-axis kinematics and vat photopolymerization, enabling the efficient, support-free manufacturing of intricate functional components. The developed algorithm successfully demonstrated the structure with 90 degree self-supporting angle with over 15% resin saving.