As-Continuous-As-Possible Ceramics Printing for Shell Models

We propose a novel computational framework for fabricating thin shell models on an extrusion-based Cartesian 3D printer with the clay material. Extrusion-based ceramics printing involves several inevitable challenges to achieve acceptable print quality, including continuous toolpath with the minimal number of transfer moves, separation of non-model and model structures, etc. Inertia of the extruded material may damage the surface quality during transfer moves. The viscosity also makes support material hard to remove. These challenges even increase for thin shell surfaces, as both sides are of visual significance, making it impossible to hide any intermediate structures in the interiors. To conquer these challenges, we adopt a curved layer scheme for ceramics printing. Then we introduce an original criterion "one-path patch" (OPP), for representing a shell surface patch that can be traversed in one path in the context of curved layer printing considering fabrication constraints. We propose a bottom-up OPP merging procedure for decomposing the given shell surface into a minimal number of OPPs and generating the "as-continuous-as-possible" (ACAP) toolpath. Furthermore, we customize the path planning algorithm with a decoupled orientation and support structures computation method. Results demonstrate that our ACAP algorithm prints shell models with both efficiency and surface quality.