Influence of Material-Related Aspectsof Additive and Subtractive Ti-6Al-4VManufacturing on Energy Demandand Carbon Dioxide Emissions

The additive manufacturing of metal parts represents a promising process that could beused alongside traditional manufacturing methods. The research scenario in this field isstill largely unexplored, as far as the technological solutions adopted to integrate differentprocesses 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 beenanalyzed and compared using a cradle-to-grave life cycle–based approach. The productionof components made of the Ti-6Al-4V alloy has been assumed as a case study. Theproposed methodology is able to account for all of the main factors of influence on energydemand and carbon dioxide emissions when the component shape is varied. The resultsprove that, besides the direct energy intensity of the manufacturing processes, the impactsrelated to material usage are usually dominant. Therefore, when complex geometries haveto be manufactured, the additive manufacturing approach could be the best strategy, if itenables a larger amount of material savings than conventional machining. Vice versa, whena small amount of material has to be machined off, the high energy intensity of an EBMprocess has a negative effect on the performance of the process