Design for Additive Manufacturing Considering Optimization of Part Topology and Build Orientation
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 design tools 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 structures that are influenced by part topology and build orientation. Reducing support structures will limit manufacturing time and cost, allowing industry to further utilize the benefits of topology optimization. Previous works addressing approaches to limit supported surface area and support material often rely on the finite element discretization scheme, leading to a gap between solving academic and practical problems. Focusing on a practical design tool, 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, dependence on the finite element discretization scheme is mitigated. 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. Depending on build orientation initialization and the test problem, support material reduction was on the order of 80%, with a tradeoff of less than 5% in structural performance.