The latter provides directly useful continuous deposition paths with equidistance however, the design space is severely restricted by the contour-offset path pattern, i.e., all the deposition paths follow the shape of the structural boundary. The former employed the pointwise different raster angles which provides the largest design space however, the discrete angle optimization result cannot be directly used for 3D printing, since it is non-trivial to derive equidistant continuous tool paths from the disorganized raster angles.
In this way, the topology optimization of the targeted problem evolves from the traditional material/void interface design to a more sophisticated problem involving multiple levels of design freedom listed as follows:įor topology optimization with material anisotropy, the methods are conventionally categorized into two groups: topology optimization with discrete raster angles and topology optimization with continuous raster angles.
#MULTIPATCH NOT WORKING PATCH#
Based on this background, a hybrid topology optimization method of design for multipatch FDM 3D printing is proposed in this paper, in which a printing layer is disintegrated into multiple patches and each patch has its unique direction of the zigzag-type filament deposition. However, the anisotropic material properties were often ignored by the topology optimization works for FDM printing. On the other hand, optimizing the filament deposition paths will provide an extra possibility to enhance the structural performance. To approach the reality, topology optimization for AM should deal with these directional variations. Specifically, the tensile modulus and strength in the raster direction, the transverse direction, and the build direction are all evidently different. The directional material properties are rooted in the layer-by-layer deposition process, which is a feature of the fused deposition modeling (FDM) technique. Among these topics, the design constraints imposed by the anisotropic properties of AM materials are of interest and will be addressed by the hybrid topology optimization technique proposed in this work. Despite the efforts, a lack of solutions is still the common issue in the topology optimization for AM as summarized by the literature. Detailed reviews on these topics can be found in. However, there are new design rules and unique constraints induced by AM, which introduce new challenges such as support structure design/elimination, minimum component size constraints, directional material properties, topology design interpretation, variable-density cellular structure design, and many others. Because the shape and topology are concurrently designed, topology optimization makes the greatest design freedom possible compared with shape-only or size-only optimization. Topology optimization has been treated as the main computational design method for AM. Several numerical examples were investigated to verify the effectiveness of the proposed method, while satisfactory optimization results have been derived. An asynchronous starting strategy is proposed to prevent the local minimum solutions caused by the concurrent optimization scheme. With this set-up, a concurrent optimization problem was formulated to simultaneously optimize the topological structure of the printing layer, the multipatch distribution, and the corresponding deposition directions. The level set method was employed to represent and track the layer shape evolution discrete material optimization (DMO) model was adopted to realize the material property interpolation among the patches. The ‘multipatch’ concept consists of each printing layer disintegrated into multiple patches with different zigzag-type filament deposition directions. This paper presents a hybrid topology optimization method for multipatch fused deposition modeling (FDM) 3D printing to address the process-induced material anisotropy.
0 kommentar(er)
