Design for additive manufacturing: 3D simultaneous topology and build orientation optimization

The primary driver for technological advancement in design methods is increasing part performance and reducing manufacturing cost. Design optimization tools, such as topology optimization, provide a mathematical approach to generate efficient and lightweight designs; however, integration of this design tool into industry has been hindered most notably by manufacturability. Innovative processes, such as additive manufacturing (AM), have significantly more design freedom than traditional manufacturing methods, providing a means to develop the complex designs produced by topology optimization. The layer-wise nature of AM leads to new design challenges such as the need for support material, influenced by part topology and build orientation. Previous works addressing approaches to limit support material often rely on the finite element discretization scheme, leading to a gap between solving academic and practical problems. This study presents an approach to simultaneously optimize part topology and build orientation with AM considerations. Utilizing the spatial density gradient in the topology optimization formulation, the dependence on the finite element discretization scheme is reduced. The proposed approach has the potential to significantly decrease support material, while having a minimal impact on structural performance. Both 2D and 3D academic test problems, as well as an aerospace industry example, demonstrate the proposed methodology is capable of generating high-quality designs.