Influence of Material-Related Aspects of Additive and Subtractive Ti-6Al-4V Manufacturing on Energy Demand and Carbon Dioxide Emissions

The additive manufacturing of metal parts represents a promising process that could be used alongside traditional manufacturing methods. The research scenario in this field is still largely unexplored, as far as the technological solutions adopted to integrate different processes are concerned and in terms of environmental and economic impact assessment. In this article, an electron beam melting (EBM) process and a machining process have been analyzed and compared using a cradle-to-grave life cycle-based approach. The production of components made of the Ti-6Al-4V alloy has been assumed as a case study. The proposed methodology is able to account for all of the main factors of influence on energy demand and carbon dioxide emissions when the component shape is varied. The results prove that, besides the direct energy intensity of the manufacturing processes, the impacts related to material usage are usually dominant. Therefore, when complex geometries have to be manufactured, the additive manufacturing approach could be the best strategy, if it enables a larger amount of material savings than conventional machining. Vice versa, when a small amount of material has to be machined off, the high energy intensity of an EBM process has a negative effect on the performance of the process.