The Additive Manufacturer Green Trade Association (AMGTA) is the first and only organization dedicated to sustainability in 3D printing. Since it was founded in 2019, it has slowly built up membership and advocated on behalf of sustainable additive manufacturing (AM) industry practices. Key to its mission, however, is the actual study of energy and material use in 3D printing. And while it has executed research into the topic via member organizations and partners, the AMGTA has just released its first independent study.
Titled “Comparative LCA of a Low-Pressure Turbine (LPT) Bracket by Two Manufacturing Methods,” the report, commissioned by the AMGTA and authored by the Rochester Institute of Technology’s Golisano Institute of Sustainability, is a life cycle assessment (LCA) of a commercial aerospace low-pressure turbine bracket. The result of two years of research, the paper compares the impact of producing the part using metal laser powder bed fusion with CNC machining, as well as how a 50 percent weight reduction impacts the life of an aircraft. Ultimately, the study was unable to determine which manufacturing method used more energy, but it did confirm that lightweighting commercial aircraft engines and airframes has a dramatic effect on carbon emissions.
“The release of this peer-reviewed LCA—the first of its kind—represents a milestone for the AMGTA,” said Sherri Monroe, the AMGTA’s Executive Director. “For the first time, we are able to publish tangible results demonstrating the importance of design in additive manufacturing when compared to traditional methods. This study demonstrates the very real impact that AM can have in aircraft and engine design of the future, and bodes well for using similar strategies in other industries and programs.”
The bracket studied was one of 12 meant to attach fuel manifolds to the external cases of the low pressure turbine modules of two GE Aviation CF6-80C2B6F turbine engines onto a Boeing 767. The part, selected for its simplicity and ease-of-access, was resdesigned for additive and produced by AMGTA member Sintavia on an EOS M290 3D printer using Höganäs AB Inconel 718 powder. Meanwhile, the traditional counterpart was CNC’d by a Tennessee-based machine shop.
The optimized AM bracket weighed 50%, or 0.063 kg, less than the original version, while boasting enhanced mechanical properties, including increased fatigue life, according to Sintavia. In turn, the research estimated that carbon emissions would be cut by 13,376 kg for ever 1 kg of weight reduction.
“This study underscores the importance of using AM to develop optimized parts and components that have been lightweighted via AM technology,” said Brian Neff, Sintavia’s CEO and the Chair of the AMGTA. “No other currently viable commercial technology offers such an immediate impact to carbon emissions as lightweighting aircraft parts via AM does, and we now have independently verified, peer-reviewed data proving so. We look forward to working with Boeing, GE, and all of the industry’s OEMs as they look to unleash the sustainable potential of AM across existing and future platforms.”
The AMGTA noted that the inconclusive nature of the first finding actually demonstrated an improvement compared to previous, similar research that showed AM to use more energy than traditional methods. Two of three LCA methodologies suggested that the traditional bracket required less energy to produce, while one indicated that the 3D printed bracket produced fewer emissions. The LCA was performed in accordance with ISO 14040:2006(E) and was peer-reviewed by EarthShift Global.
Previous studies, as well as this one, have argued that source energy trumps other factors in terms of determining the greenhouse gas emissions of the manufacturing technology itself. This is obviously because the nature of the energy source determines whether or not the energy use is contributing more or less to global warming. Therefore, a facility running entirely on solar power, for instance, would be more sustainable than one plugged into a fossil fuel energy grid. While this is true, it is important to note that this isn’t the end-all-be-all of the situation, as running on renewables is not a long-term solution to resource use.
“The two phases of this study – production and use – have implications well beyond this specific bracket, airplane, or manufacturing sector,” Sherri Monroe added. “The negligible difference in environmental impacts during production combined with the benefits of on-demand production – when you want it, where you want it, how you want it – to deliver more resilient, efficient, and sustainable supply chains, have significant implications for the manufacturing ecosystem to deliver more sustainable solutions. While this study has immediate implications for aircraft engine and airframe manufacture, the findings in the use phase extend to any part of an airplane that could potentially be lightweighted – mechanical systems, seats, service carts, galleys – and well beyond aircraft to any equipment moved by an engine or motor – vehicles, ships, trains, robots – although the energy demands for aerospace make it the biggest, most obvious and most immediate beneficiary.”
This is just the first independent study from the AMGTA. The organization will publishing other independent research throughout the year. This is no doubt part of a trend that we will see played out as nations globally seek to re-shore and decarbonize manufacturing. In many ways, AM represents low-hanging fruit when it comes to decarbonization as an immediate and increasingly qualified manner of reducing carbon emissions on existing systems. However, the cost of the technology is still too high for widespread deployment, necessitating stimulus, which is what we’re seeing internationally. AMGTA will naturally play a vital role in this regard, continually proving out the sustainable potential of the technology. As a result, the organization will only grow at a rapid pace.
Images courtesy of AMGTA.