Eco-Assessment of Design for Additive Manufacturing Solutions Defined at Different Levels of Detail

In recent years, Additive Manufacturing (AM) proved to be extremely competitive in the production of small lots of pieces with high customization. Compared to subtractive production, AM allows to make less waste of material and reproduce highly complex components without increasing their costs. Some studies also assessed the environmental advantages of AM, which could be significant in the event of its future large scale diffusion. However, an environmental assessment considering the aspects of hierarchical complexity that can be obtained with AM is missing in literature. This study bridges this gap by evaluating and comparing the environmental impacts resulting from the implementation of different design for AM options defined at different levels of detail, e.g. shape, cellular internal structure and infilling. For each option, the environmental impact arising from the mass and energy of manufacturing was calculated. The data were obtained through virtual simulations with commercial software for design for AM (i.e. nTopology) and experimentation with a 3D printer that produces pieces in polylactic acid (PLA). The obtained results highlighted the preponderant role of energy consumption deriving from the path of the print head in defining the environmental impacts, with respect to the quantity of material in the piece. In particular, we have seen how the shape and infill optimization (if the density is lower than 50%) reduce the environmental impacts, while the lattice structure optimization increases them, due to the more energy and time-consuming printing process.