Fused deposition modeling (FDM) is a well-known additive manufacturing process that can fabricate complex 3D models with simple layer-by-layer material deposition. In recent years, multi-axis FDM has been rapidly developing and is considered a solution to overcome the limitations of conventional 2.5D FDM, such as the need for excessive support structures and the staircase effect. Specifically, the newly added rotational degrees of freedom allow local print direction adjustment and curved layer deposition to reduce overhanging and enhance surface quality. However, a more sophisticated process planning is required to realize the above benefits. Furthermore, printability (e.g., collision-free printing) cannot be guaranteed due to the flexibility of multi-axis FDM, unlike 2.5D FDM. Therefo...[ Read more ]

Fused deposition modeling (FDM) is a well-known additive manufacturing process that can fabricate complex 3D models with simple layer-by-layer material deposition. In recent years, multi-axis FDM has been rapidly developing and is considered a solution to overcome the limitations of conventional 2.5D FDM, such as the need for excessive support structures and the staircase effect. Specifically, the newly added rotational degrees of freedom allow local print direction adjustment and curved layer deposition to reduce overhanging and enhance surface quality. However, a more sophisticated process planning is required to realize the above benefits. Furthermore, printability (e.g., collision-free printing) cannot be guaranteed due to the flexibility of multi-axis FDM, unlike 2.5D FDM. Therefore, in this thesis, we aim to solve the process planning of multi-axis FDM through a scalar field-based framework to achieve a feasible multi-axis printing process that reduces support and improves surface quality.

First, we present the printing scalar field generation that implicitly determines the curved print slices, where each print slice is an iso-surface of the scalar field. The B-spline volumetric scalar field is formulated and optimized to obtain printable curved print slices with reduced overhanging and improved surface quality. Second, we propose the support generation algorithm based on the tetrahedral mesh to construct the self-supported curved pillars under the overhanging regions, where each pillar is a tetrahedral (sub-)mesh with an embedded printing scalar field. Third, we solve the print sequencing problem to determine a sequence of curved print slices that satisfy self-support and collision-free requirements. Specifically, partition-based print sequence planning is proposed to determine an optimized sequence that minimizes the air-moves, and adaptive slicing is presented to select the suitable print slices. Computer simulations and printing experiments have been performed, and the results provide a firm confirmation of the feasibility and effectiveness of the presented methodologies.