Fluid flow-inspired curvature-aware print-paths from hexahedral meshes for additive manufacturing

Abstract

Conventional manufacturing methods create objects by removing material via subtractive processes such as milling, drilling, and carving. In contrast, additive manufacturing (AM) deposits material to fabricate parts, which enables the manufacturing of more sophisticated geometries. Planar slicing methods, where layers are always parallel to the XY plane and on the Z axis, are traditionally used in AM to build 3D models layer by layer. However, quite a few hardware platforms have been developed for enabling the use of multi-axis AM with inputs of three-dimensional curves. These curves can be considered as print-paths and represent parts. This situation can be likened to using curved tool-paths in subtractive manufacturing. Models represented using curves conforms better to the part's geometry than those obtained by planar slicing methods. This also enables improved mechanical strengths in the printed parts. %One of the interesting studies done in recent years can be shown to obtain the print path for AM using hexahedral meshes. % Hexaehdral meshes are preferred both because they interpolate the surface feature curves of the model and represent them well in the surface curvature directions, and also because of the cuboid structures that we will use in this study. Thanks to recent improvements, computational methods are able to produce high-quality hexahedral meshes, whose hexahedrons are arranged along the principal curvature directions of the input surfaces. Curvature-aware print-paths, proposed by Gunpinar, follow these curvature directions and have enabled a reduction in stair-stepping effect in the printed parts. However, crosswise-contacts can exist between the print-paths (i.e., print-paths are quasi-perpendicular to each other), which is undesirable as failures may occur particularly at those contact regions. Therefore, the present work aims at generation of curvature-aware print-paths (similar to the print-path generation technique of Gunpinar) without crosswise-contacts between them. To solve this problem, we inspire from fluid flow and imitate (laminar) streamlines for an inlet and an outlet of a duct for designing curvature-aware print-paths. A hexahedral mesh is decomposed into blocks (cuboid-like sub-volumes), each of which is covered with fluid flow-inspired print-paths. A multi-axis (collision-free) additive manufacturing (AM) planning technique is also proposed. As a proof of concept, fluid flow-inspired curvature-aware print-paths are validated using a multi-axis AM simulator and machine.