A support structure design strategy for laser powder bed fused parts

Metal Additive Manufacturing technologies are becoming more and more relevant for industrial component mass production. Among the various technologies developed and under development, one of the most important is the Laser Powder Bed Fusion (LPBF). The use of this technology for mass production rises several issues that typically are not considered in research and development, such as process reliability and material waste reduction. Process reliability depends on both the process itself and component design, which needs to consider the integration of component design and support design. Support design needs to be considered since the early component design because it strongly affects the whole business case behind the development of a component produced via LPBF. In fact, it potentially affects the production time, part post-process, and material waste (melted and powder). The understanding of the first and second point is quite straightforward: the more supports, the more production time and post-process need. The third point shall be interpreted considering that support structure design determines both the amount of melted material that will be discarded during the post process and the possibility to get back un-melted powder. Considering that in the production of a real part, even though it is designed for additive, typically supports represents a significant percentage of the whole building, their correct design is fundamental for the LPBF competitiveness as a manufacturing technology. The aim of this paper is to propose an approach to design support structures integrated in the part design that satisfy manufacturability constraints and allowing, at the same time, to reduce material waste enhancing powder recycling.