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Over the last years, additive manufacturing (AM) has been gathering momentum both in the academic and in the industrial world. Besides the obvious benefits in terms of flexibility and process capabilities, the environmental performance of such processes has still to be properly analyzed. Actually, the advantages of additive manufacturing over conventional processes are not obvious. Indeed, different manufacturing approaches result in different amounts of involved material and in different processing energy demands. Environmental comparative analyses are hence crucial to properly characterize AM processes. In this paper, an energetic comparison between the emerging wire arc additive manufacturing (WAAM) process and a traditional machining-from-bulk solution to produce a steel blade is presented. A methodology accounting for all the material and energy flows of the whole component life cycle is proposed. Experimental measurements and environmental databases are used to quantify the primary energy demand at each stage of the life cycle. The results reveal that, for the analyzed case study, an integrated additive (WAAM)-subtractive manufacturing route enables significant material and primary energy savings with respect to traditionally applied approaches.

Sustainability is an essential consideration in manufacturing, and within this chapter a detailed appraisal is given to sustainability for 3D printing. An in-depth review of existing research is provided, and a cradle-to-grave assessment technique is shown to assess the environmental impact of 3D printed part.

The applicability domain of Additive Manufacturing (AM) processes, apart from technological and quality results, relies on environmental and cost performance. These aspects still need to be better understood. To this aim, comparative analyses with conventional manufacturing routes are needed. In this paper, empirical cost and energy requirement models are suggested to assess subtractive- (machining) and additive- (Electron Beam Melting) based manufacturing approaches for the production of Ti-6Al-4V components. A life-cycle perspective is adopted, and all the steps from the input material production to the post-AM processing operations and the use phase are included. The analyses have been carried out considering the shape of the component, the light-weighting capabilities and the utilization time as the main factors of influence. The proposed modelling effort has allowed different decision-support charts, which are suitable for identifying the most energy-efficient or economically-advantageous manufacturing approach, to be obtained. The results have revealed that, for the considered case study, EBM could be a more energy-efficient approach than conventional machining, even without re-designing the component, due to the higher efficiency in raw material usage. As far as cost is concerned, the additive-based approach only becomes the preferable solution when the cost savings during the use phase are accounted for.

The number of scientific papers in the field of Sustainable Manufacturing (SM) shows a strong growth of interest in this topic in the last 20 years. Despite this huge number of publications, a clear statement of the profound meaning of Sustainable Manufacturing, or at least a strong theoretical support, is still missing. The 6R framework seems to be a first attempt to rationalize this issue, as it is an axiomatic identification of its true nature. Recognizing the pursuing of one or more of the Reduce-Recycle-Reuse-Recover-Redesign-Remanufacture principles allows users to identify if any manufacturing action is in the right direction of sustainability. In the paper, the authors speculate on the use of this framework and its possible extension by referring to all the existing scientific contributions on Sustainable Manufacturing in the SCOPUS® databases as a source of data. Starting from the measurement of the distribution of the scientific papers allocated onto the 6Rs dimensions, by using both author keywords and automatically extracted multiword from texts, the distribution of the scientific papers among the 6R was derived. A new framework is proposed based on analytical text tools to compare the affinity of the applied research activities of the Italian Technologist network SOSTENERE to sustainable manufacturing and provide also a benchmarking view to describe the Italian way to SM with respect to the rest of existing applications.

In order to characterise the environmental performance of additive manufacturing (AM) processes, comparative analyses are required. Different manufacturing approaches (such as additive and subtractive ones), besides adopting different equipment, use different kinds and amounts of material. Therefore, the material-related flow has to be followed throughout the entire product life. Differences in environmental impact arise at each step of the life cycle: material production, manufacturing, use, disposal, and transportation. A life cycle-based methodology able to take due account of all the factors of influence on the total energy demand for the production of metal components is given in this paper. Decision support tools for identifying the most sustainable manufacturing route (subtractive versus AM-based approaches) are presented for different scenarios. The aim of the present paper is to contribute to the debate concerning the environmental impact characterisation of AM processes.

The reduction of CO2 emissions is an urgent objective to pursue. The scientific and the industrial world have gathered such challenge, starting to find out energy- and resource-efficient manufacturing strategies. From the literature review, in the domain of environmental impact analysis of manufacturing processes, two relevant knowledge gaps can be spotted: (1) the metal forming processes (and, in particular, the bulk forming processes) are still not well documented, and (2) there is a lack of systematic and comparative studies on energy and material flows enabling the identification of environmentally-friendly manufacturing design strategies. This research offers a contribution to a better understanding of the environmental impact of forming and machining processes. The performance of the two processes is evaluated and compared with the varying of the material usage related factors. The impacts on the final results of the aluminum recycling strategy as well as of the applied method to account for benefits of recycling are analyzed. Therefore, the paper represents an effort aimed at tuning and improving a methodology able to thoroughly analyze the environmental impact of a given process, and to better compare different manufacturing strategies from the environmental point of view.