Metal Additive Manufacturing Conference 2019

Abstract Laser Powder Bed Fusion (L-PBF) is a manufacturing technology based on layer-by-layer material additions of fused metal powder. One important characteristic of this technology is its capability to produce components with highly complex geometries. The L-PBF process requires support structures that connect the components to a substrate plate in the machine. These support structures have two main functions: The first is to dissipate the generated heat when melting the material; the second is to constrain the solidified material to ensure geometrical accuracy of the component. The latter is especially relevant for the downward facing surfaces with lower overhang angles which might collapse without support structures. Overhang angle is defined as the angle between a tangent plane to a downward facing surface in a component and the substrate plate; usually critical angle, describing the manufacturability of a feature without support structures, is defined for a specific L-PBF process and material. Depending on the component geometry, a considerable amount of support structures is necessary to ensure manufacturability. After the L-PBF process, all the supports need to be removed - which can amount to a time-consuming task that increases overall product cost. This serves as a motivation to design easily removable support structures. The approach presented in this study aims at designing L-PBF supports as lattice structures. Lattice structures are often used to reduce component mass in lightweight applications, sometimes with complex heat transfer functionalities. These properties can be used for improved designs of support structures and they can be further optimized for better removability. In this study, different types of lattice-based support structures are used for a Siemens gas turbine component - a resonator box - and their production time and removability are compared. The results can be used to design optimal support structures for other similar components.