Algorithms for Layered Manufacturing in Image Space
Pu Huang, Charlie C. L. Wang, Yong Chen · ASME Press eBooks · 2014
Layered manufacturing plays an important role in industry. It fabricates an input 3-D model by adding material in the layer-by-layer pattern. Layered manufacturing is widely used in applications such as biomedical engineering, aerospace industry, and automotive industry. Most layered manufacturing processes require the input model to be represented in STereoLithography (STL) format, which defines the object as a raw unstructured triangulated surface by the unit normals and vertices (ordered by the right-hand rule) of the triangles using a 3-D Cartesian coordinate system. A set of parallel planes are used to intersect with the triangulated surface of the object as the slicing strategy, and the intersection contours are traced on each slice. Non-manifold features like self-intersection, degenerated triangles, or gaps will always lead to problematic contours. The existing commercial software packages implement heuristic rules to deal with such problematic contours. For example, cutting the singular point at which the contour has a self-intersection (as shown in Figure.15.1). However, these heuristic rules do not fundamentally solve the problem. Consequently, incorrect part region classification will lead to incorrectly fabricated layers, either with unwanted gaps (see Figure.15.2 from [1]) or membranes. The models shown in Figure.15.2 are fabricated by fused deposition modeling (FDM). In this chapter, we investigate robust and efficient approaches for layered manufacturing process planning directly applied on an implicit solid, which is reconstructed from point cloud or volumetric images in the reverse engineering context.