Topology Optimization for Additive Manufacturing: Considering Maximum Overhang Constraint

Abstract

Additively manufactured components often require temporary support material during the 3D printing process. In the case of polymer material process such as Fuse Deposition Modeling (FDM), the support material can be dissolved away. However in the case of metals in a selective laser melting (SLM) process, the support and component material are one in the same. Since the support structure adds both material cost and post-processing cost to every component printed, it is desired to limit or completely eliminate the need for such material. As such, it is proposed to take advantage of the maximum printable overhang angle (the angle at which the AM process requires no support material) by harnessing topology optimization as the design engine. This is accomplished through a topology optimization projection scheme, in which the angle constraint is imposed through a Heaviside projection and not applied as an explicit constraint. Solutions to two standard topology optimization problems are included and show good agreement with the overhang constraint.