Abstract:

With the development of additive manufacturing (3D printing), light-weighting of 3D models is one of the research hotspots today. A weak-balance light-weighting modeling method to generate internal filling structures for 3D printed objects is presented. This scheme can generate varying internal filled density according to structural analysis of 3D models automatically. This method involves three necessary steps. A cross-sectional structural analysis method is used to analyze the stress distribution and weak parts of a 3D object. A hybrid offsetting algorithm is used to offset the model by a given distance. Based on the stress analysis, a continuous density distribution of points on the offsetting mesh is generated using an improved Poisson-disk sampling. Parts where exist high stress, sampling points are dense, otherwise sampling points are sparse. The weakly balanced octree technique, body centered cubic (BCC) and Delaunay 3D algorithm are used to transfer the offsetting model into a tetrahedral model which is “internal grading” and “weak density”. Then tetrahedrons of the tetrahedral model are used to generate the “Frame-Node” structure. The weak-balance light-weighting scheme areallows us to implement different filled density for different parts based on stress analysis, which can achieve global optimization.

Key words: “Frame-Node” structure, stress analysis, tetrahedral mesh, the weakly balanced octree, weak-balance light-weighting filling