Additive manufacturing (AM) holds great potential for improving materials efficiency, reducing life-cycle impacts, and enabling greater engineering functionality compared to conventional manufacturing (CM), and AM has been increasingly adopted by aircraft component manufacturers for lightweight, cost-effective designs. This study estimates the net changes in life-cycle primary energy and greenhouse gas emissions associated with AM technologies for lightweight metallic aircraft components through the year 2050, to shed light on the environmental benefits of a shift from CM to AM processes in the U.S. aircraft industry. A systems modeling framework is presented, with integrates engineering criteria, life-cycle environmental data, aircraft fleet stock and fuel use models under different AM adoption scenarios. Estimated fleet-wide life-cycle primary energy savings at most reach 70-173 million GJ/year in 2050, with cumulative savings of 1.2-2.8 billion GJ. Associated cumulative GHG emission reductions were estimated at 92.1-215.0 million metric tons. In addition, thousands of tons of aluminum, titanium and nickel alloys could be potentially saved per year in 2050. The results indicate a significant role of AM technologies in helping society meet its long-term energy use and GHG emissions reduction goals, and highlight barriers and opportunities for AM adoption for the aircraft industry.

# Springer-Verlag (outside the USA) 2011Abstract Purpose The use of carbon fiber-reinforced polymer matrix composites is gaining momentum with the pressure to lightweight vehicles; however energy intensity and cost remain major barriers to the wide-scale adoption of this material for automotive applications. This study determines the relative life cycle benefits of two precursor types (conventional textile-type acrylic fibers and renewablebased lignin), part manufacturing technologies (conventional SMC and P4), and a fiber recycling technology. Materials and methods A representative automotive part, i.e., a 30.8-kg steel floor pan having a 17% weight reduction potential with stringent crash performance requirements, has been considered for the life cycle energy and emissions analysis. Four scenarios-combinations of the precursor types and manufacturing technologies-are compared to the stamped steel baseline part. Results and discussion The analysis finds the lignin-based part made through P4 technology to offer the greatest life cycle energy and CO 2 emissions benefits. Carbon fiber production is estimated to be about 14 times more energyintensive than conventional steel production; however, life cycle primary energy use is estimated to be quite similar to the conventional part, i.e., 18,500 MJ/part, especially when considering the uncertainty in LCI data that exist from using numerous sources in the literature. ConclusionsThe sensitivity analysis concludes that with a 20% reduction in energy use in the conversion of lignin to carbon fiber and no energy use incurred in lignin production since lignin is a by-product of ethanol and paper production, a 30% reduction in life cycle energy use could be obtained. A similar level of life cycle energy savings could also be obtained with a higher part weight reduction potential of 43%.

No abstract

No abstract

SummaryAdditive manufacturing (AM) holds great potentials in enabling superior engineering functionality, streamlining supply chains, and reducing life cycle impacts compared to conventional manufacturing (CM). This study estimates the net changes in supply-chain lead time, life cycle primary energy consumption, greenhouse gas (GHG) emissions, and life cycle costs (LCC) associated with AM technologies for the case of injection molding, to shed light on the environmental and economic advantages of a shift from international or onshore CM to AM in the United States. A systems modeling framework is developed, with integrations of lead-time analysis, life cycle inventory analysis, LCC model, and scenarios considering design differences, supply-chain options, productions, maintenance, and AM technological developments. AM yields a reduction potential of 3% to 5% primary energy, 4% to 7% GHG emissions, 12% to 60% lead time, and 15% to 35% cost over 1 million cycles of the injection molding production depending on the AM technology advancement in future. The economic advantages indicate the significant role of AM technology in raising global manufacturing competitiveness of local producers, while the relatively small environmental benefits highlight the necessity of considering trade-offs and balance techniques between environmental and economic performances when AM is adopted in the tooling industry. The results also help pinpoint the technological innovations in AM that could lead to broader benefits in future. Keywords:additive manufacturing industrial ecology injection molding life cycle assessment (LCA) life cycle costing (LCC) supply chain management Supporting information is linked to this article on the JIE website

No abstract

No abstract

No abstract