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Funding Information: João Pedro Oliveira acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia , I.P., in the scope of the projects LA/P/0037/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. This activity has received funding from the European Institute of Innovation and Technology (EIT) – Project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. This body of the European Union receives support from the European Union’s Horizon 2020 research and innovation programme . Publisher Copyright: © 2023 The Authors The industrial progress made throughout these years has led to great results in terms of producing fast and with good quality. However, the impacts related to that production, whether these are environmental, economic, or social have been, at times, neglected. The manufacturing sector, as one of the most polluting sector, felt the urge to adapt to this industrial progress and find ways to produce with improved sustainability goals without compromising the quality of the final product and the production time. Industry easily understood the benefits of this greener approach, and, with this, new sustainable technologies started to emerge. Additive Manufacturing (AM) is one of those technologies that provide alternative sustainable paths to traditional manufacturing. In order to generalize the benefits of AM production in terms of sustainability, when compared to traditional processes, further investigations must be conducted. In this sense, the proposed work has the intention of finding the environmental impacts associated with a particular AM technique for the fabrication of metal parts, Wire Arc Additive Manufacturing (WAAM). A practical work based on the production of three different complexity metal parts considering an additive (WAAM) and a subtractive (Computer Numerical Control (CNC) Milling) manufacturing process is developed. To quantify the environmental impacts of both processes, the author resorts to the Life Cycle Assessment (LCA) methodology. The assessment is conducted in the SimaPro 9.2 software, accordingly to ISO 14044:2006 standard. The results allow a comparison between both types of manufacturing and enable the suggestion of measures to decrease the environmental footprint of WAAM. It was found that WAAM approach leads to a material saving ranging between 40% and 70% and an environmental impact reduction in the range of 12%–47%, compared to the subtractive approach for fabricating the 3 geometries considered in this study. The conclusions obtained are specific to this particular application and, once more, it is acknowledged that in order to reach a global understanding relative to this technology's environmental implications, extra research still needs to be made. publishersversion published

Funding Information: Inês Ferreira acknowledges financial support from Fundação para a Ciência e Tecnologia for funding PhD Grant - REF: SFRH/BD/145448/2019. Helena Carvalho and Radu Godina acknowledge Fundação para a Ciência e a Tecnologia (FCT - MCTES) for its financial support via the project UIDB/00667/2020 (UNIDEMI). Publisher Copyright: © 2022 The Authors The role of new technologies such as additive manufacturing and blockchain technology in designing and implementing circular economy ecosystems is not a trivial issue. This study aimed to understand if blockchain technology can be an enabler tool for developing additive symbiotic networks. A real case study was developed regarding a circular economy ecosystem in which a fused granular fabrication 3D printer is used to valorize polycarbonate waste. The industrial symbiosis network comprised four stakeholders: a manufacturing company that produces polycarbonate waste, a municipality service responsible for the city waste management, a start-up holding the 3D printer, and a non-profit store. It was identified a set of six requirements to adopt the blockchain technology in an additive symbiotic network, bearing in mind the need to have a database to keep track of the properties of the input material for the 3D printer during the exchanges, in addition to the inexistence of mechanisms of trust or cooperation between well-established industries and the additive manufacturing industry. The findings suggested a permissioned blockchain to support the implementation of the additive symbiotic network, namely, to enable the physical transactions (quantity and quality of waste material PC sheets) and monitoring and reporting (additive manufacturing technology knowledge and final product's quantity and price). Future research venues include developing blockchain-based systems that enhance the development of additive symbiotic networks. publishersversion published

Given the current environmental concerns related to manufacturing, the introduction to the industrial symbiosis concept brought purpose to waste, instead of disposing it in landfills or eliminating it through incineration. The waste generated by industrial processes, or end-of-life products, is redirected to be used as a “new” input in another process by one or more organizations, which is a mutual benefit or a “symbiosis”. Despite its relevancy, the industrial symbiosis concept is marginally explored in the context of additive manufacturing; this emerging technology has disruptive potential regarding the use of different materials as secondary raw materials. This paper presents a systematic literature review regarding industrial symbiosis and additive manufacturing. The main objective is to identify how wastes can be used as input materials to additive manufacturing processes and what exchanges of resources occur in an industrial symbiosis setting. A final sample of 32 documents was reached and analyzed. Five examples of using waste streams in additive manufacturing processes to produce goods were highlighted and explored. publishersversion published

The industrial progress made throughout these years, allowed to obtain great results in terms of producing fast and with good quality. However, the impacts related to that production, whether these are environmental, economic, or social have been, at times, neglected. The manufacturing sector, as one of the most pollutants, felt the urge to adapt to this industrial progress and find ways to produce with a greener mentality without compromising the quality of the final product and the production time. The industry easily understood that they could only benefit from this approach, given the fact that a greener mentality involves a series of factors that limit the need for reinvestments. Society itself has also become more environmental aware and stricter environmental legislations have been created. Consumers started prioritizing greener products and sustainable productions that comply with those legislations. With this in mind, new sustainable technologies emerge and improvements to the technol- ogies that already exist are made. Additive Manufacturing (AM) is one of the revolutionary technologies that provides alternative and more sustainable paths to the traditional manufacturing. The proposed work has the intent of recognizing the environmental impacts associated with a particular AM technique for the fabrication of metal parts, the Wire Arc Additive Manufacturing (WAAM). Firstly, a global overview on AM processes is made. Afterwards, WAAM is analyzed with further detail identifying, through literature, the main challenges underlying. In order to validate some of these chal- lenges found, three case studies were conducted considering the Life Cycle Assessment (LCA) method- ology. The practical work was based on the production of different complexity metal parts considering an AM process and, for greater context on the subsequent results, a subtractive manufacturing process. The quantification of the environmental impacts not only allowed a comparison between both types of manufacturing but also enabled the identification of the main environmental hotspots and conse- quently the suggestion of measures to decrease the impacts related to them. The results were obtained for this particular application and it is acknowledged that in order to reach a global understanding rel- ative to this technology's environmental implications, extra research still needs to be made. Os progressos industriais realizados ao longo destes anos, permitiram obter grandes resultados em termos de uma produção rápida e de boa qualidade. Contudo, os impactes relacionados com essa produção, sejam estes ambientais, económicos ou sociais, têm sido, por vezes, negligenciados. O sector industrial, como um dos mais poluentes, sentiu a necessidade de se adaptar a estes progressos indus- triais e encontrar formas de produzir incorporando uma mentalidade mais verde sem comprometer a qualidade do produto final e o tempo de produção. A indústria facilmente compreendeu que só poderia beneficiar desta abordagem, visto que uma mentalidade mais verde está relacionada com uma série de fatores que restringem a necessidade de reinvestimentos. A própria sociedade também se tornou mais ambientalmente consciente e criadas le- gislações ambientais mais rigorosas. Os consumidores começaram a dar prioridade a produtos mais ecológicos e a produções que cumprissem essas mesmas legislações. Com estes progressos surgiram novas tecnologias sustentáveis e as tecnologias já existentes foram melhoradas. O fabrico aditivo (FA) é uma das tecnologias revolucionárias que proporciona caminhos alternativos e mais sustentáveis para o fabrico tradicional. O trabalho proposto tem a intenção de reconhecer os impactes ambientais associados a uma técnica de FA particular, o Fabrico Aditivo através de Arco Elétrico. Em primeiro lugar, é dada uma visão geral acerca dos processos de FA. Posteriormente, o Fabrico Aditivo através de Arco Elétrico é analisado com mais detalhe e, através da literatura, são identificados os principais desafios que lhe estão subja- centes. Com o intuito de validar alguns destes desafios encontrados, foram realizados três estudos de caso considerando a metodologia de Avaliação do Ciclo de Vida (ACV). O trabalho prático baseou-se na produção de diferentes peças metálicas, considerando um processo de fabrico aditivo e, de modo a se conseguir contextualizar os resultados obtidos, um processo de fabrico subtrativo. A quantificação dos impactes ambientais permitiu, não só comparação entre ambos os tipos de fabrico como também per- mitiu a identificação dos principais pontos críticos ambientais e, consequentemente, a sugestão de me- didas para diminuir os impactos relacionados com os mesmos. É de ressalvar que, os resultados foram obtidos para esta aplicação específica e reconhece-se que para se chegar a um entendimento global relativamente às implicações ambientais desta tecnologia são necessários mais desenvolvimentos.