Citation: Dias, M.; Pragana, J.P.M.; Ferreira, B.; Ribeiro, I.; Silva, C.M.A. Economic and Environmental Potential of Wire-Arc Additive Manufacturing. Sustainability 2022, 14, 5197. https://doi.org/10.3390 /su14095197 Academic Editor: Lin Li Received: 8 April 2022 Accepted: 21 April 2022 Published: 25 April 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Economic and Environmental Potential of Wire-Arc Additive Manufacturing Manuel Dias, João P. M. Pragana , Bruna Ferreira, Inês Ribeiro and Carlos M. A. Silva * IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; manuel.e.dias@tecnico.ulisboa.pt (M.D.); joao.pragana@tecnico.ulisboa.pt (J.P.M.P.); bruna.ferreira@tecnico.ulisboa.pt (B.F.); ines.ribeiro@ist.utl.pt (I.R.) * Correspondence: carlos.alves.silva@tecnico.ulisboa.pt Abstract: Since its creation, Additive Manufacturing (AM) has experienced a tremendous growth particularly over the last decade due to the industrial paradigm shift intended for improving con- ventional manufacturing procedures. This work is focused on an emerging AM process known as Wire-Arc Additive Manufacturing (WAAM) to assess its potential for further applications involving metallic costumer-oriented parts. Contrary to most AM processes, WAAM allows deposition of material layer-by-layer to be accomplished under high deposition rates, low production times and near 100% material efficiency using accessible equipment. The work stems from evaluating the economic viability in the production of parts by WAAM as an alternative for conventional processes such as those used in traditional subtractive approaches. For that purpose, a process-based cost model (PBCM) was developed for estimating production costs using a strong technological approach. The PBCM was tested with the production of a case study part by WAAM and its environmental impact was further assessed through life cycle assessment (LCA). Results show that WAAM can be economically and environmentally viable within specific industrial contexts. Moreover, further developments and optimizations of process variables and equipment will allow this technology to mature into tackling novel production challenges in a time and cost-effective manner. Keywords: wire-arc additive manufacturing; process-based cost model; life cycle assessment; case study 1. Introduction The trend of mass customization and the need in industry for producing lightweight parts of increasingly complexity in terms of overall shape or tailor-designed features is challenging the manufacturing industry in significantly pushing production chains to their limits in a time known as the 4th Industrial Revolution [1]. In this view, the need for providing products and/or services that best fit consumption needs while maintaining near mass production efficiency is of great importance [2]. In view of the above, one technology that is nowadays standing out as a key enabler for flexible production of tailor-made end-use components with sophisticated shapes/features is Additive Manufacturing (AM) [3]. Although originally used to produce prototypes, AM it is nowadays utilized to produce fully dense parts for state-of-the-art applications in a wide variety of materials ranging from plastics, organics, ceramics and composites to metals [4]. In case of metals, the most widespread AM processes belong to the categories of Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) [5]. PBF processes work by selectively melting several beds of metallic powder placed over a platform layer-by-layer for shaping the final part. These processes use focused thermal heat sources in form of lasers or electron beams to allow printing complex parts with high resolution. However, PBF is largely affected by drawbacks associated to expensive energy and raw material consumptions, complex and costly equipment, limited envelops and Sustainability 2022, 14, 5197. https://doi.org/10.3390/su14095197 https://www.mdpi.com/journal/sustainability