Topology optimization of support structure layout in metal-based additive manufacturing accounting for thermal deformations

Abstract

This paper focusses on topology optimization of support structures for metal-based additive manufacturing. Processes based on powder bed fusion are subjected to deformations during manufacturing due to large thermal stresses. Controlling these deformations by adding temporary support structures is essential in guaranteeing qualitative end products and improving print success rates. This paper first describes an adapted stiffness tensor formulation for lattice type support structures based on a surrogate model. Next, a general inherent strain method is presented to simulate the complex thermal behaviour of the printed part. These ingredients are used in a topology optimization framework that is capable of automatically generating an optimized support structure layout to limit the vertical displacements of each layer of the printed part to a specified maximum value. The proposed framework is applied to a 2D and 3D benchmark problem to demonstrate that the vertical deformations induced during the manufacturing process are successfully reduced.