A Northwestern University team has confirmed a new way to help the airline industry save dollars while also saving the environment. And the solution comes in three dimensions. By manufacturing aircrafts’ metal parts with 3-D printing, airlines could save a significant amount of fuel, materials, and other resources.
Led by Eric Masanet, the team used aircraft industry data to complete a case study of the life-cycle environmental effects of using 3-D printing for select metal aircraft parts, a technique that is already being adopted by the industry. The team concluded that 3-D printing the lighter and higher performance parts could significantly reduce both manufacturing waste and the weight of the airplane, thus saving fuel and money and decreasing carbon emissions.
Conventional manufacturing methods tend to be inefficient and wasteful. To produce a 1-kilogram bracket for an airplane, for example, it may require 10 kilograms of raw material input into the manufacturing process. And, from an engineering design perspective, that final bracket may still contain much more metal than is required for the job. 3-D printing, on the other hand, requires far less raw material inputs and can further produce parts that minimize weight through better design.
“We have suboptimal designs because we’re limited by conventional manufacturing,” Masanet said. “When you can make something in layer-by-layer fashion, those constraints diminish.”
Masanet does not anticipate a change to the crucial parts of the aircraft, such as the wings and engine, any time soon. But he does see real potential in the replacement of less flight-critical parts, such as brackets, hinges, seat buckles, and furnishings. According to the case study, 3-D printing a bracket, for example, reduced its weight from 1.09 kilograms to 0.38 kilograms. This might not seem like much, but it adds up.
“There are enough parts that, when replaced, could reduce the weight of the aircraft by 4 to 7 percent,” Masanet said. “And it could be even more as we move forward. This will save a lot of resources and a lot of fuel.”
Journal of Cleaner Production - Energy and emissions saving potential of additive manufacturing: the case of lightweight aircraft components
If the 3-D components evaluated in the case study are used to their full potential, Masanet predicted it would greatly benefit the environment in more than one way. First, his team estimated that airplane fuel consumption could be reduced by as much as 6.4 percent, reducing both fossil fuel dependency and greenhouse gas emissions. Second, their life-cycle analysis found that manufacturing 3-D printed components uses as little as one-third to one-half of the energy currently used in conventional methods. Manufacturers would also potentially save thousands of tons of aluminum, titanium, and nickel that are otherwise scrapped every year.
But Masanet said there is one caveat. Scientists need to improve 3-D printing technology to realize the full extent of the estimated aircraft weight savings. Limitations in the process, such as issues with surface quality, residual stresses, repeatability, and throughput, are current barriers to full-scale adoption. But Masanet hopes this case study will provide further proof that continued research efforts and funding should be focused on improving the 3-D printing process.
“If we can accelerate the necessary process improvements, then we can start reaping these savings sooner,” he said. “Maybe then we can start seeing savings 10 years earlier than if we just let the technology progress at its regular rate.”
• We estimate the energy and GHG saving potentials of AM lightweight aircraft parts.
• Model includes adoption estimation, LCI, fleet stock and scenarios through 2050.
• Total fleet-wide life-cycle primary energy savings potentials is 1.2–2.8 billing GJ.
• Associated cumulative emission reduction potentials of CO2e is 93–217 million tons.
• Thousands tones of Al, Ti and Ni alloys could be saved per year in 2050.
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.
Using the full capabilities of the new parts with distributed engines would enable 50% weight reduction and further efficiency
3D printed parts would need less assembly and be cheaper to make. Frank Preli, chief engineer for materials and process engineering at the company, anticipates the possibility of radical new aircraft designs “like many engines embedded in a wing for ultra-aerodynamic efficiency.
Such a design could have many benefits, says Mark Drela, a professor of aeronautics and astronautics at MIT. Distributing engines along the trailing edge of wings and in the rear of the fuselage can theoretically cut fuel consumption by 20 percent and decrease an aircraft’s weight. These benefits “add up to very large fuel burn reductions,” Drela says. Savings of 50 percent “are not inconceivable.”
Additive manufacturing techniques need to improve to allow for higher precision. Once researchers understand the fine, molecular-scale physics of how lasers and electron beams interact with powders, he says, “that will lead to the ability to put in finer and finer features, and faster and faster deposition rates.”
Mark Drela had a 24 page paper on optimizing airplanes. Simultaneous Optimization of the Airframe, Powerplant, and Operation of Transport Aircraft
Airbus trying to create new materials to enable 3D printing and entire wing
Airbus is targeting sometime beyond 2020 to be able to fabricate an airplane wing using additive manufacturing.
EADS (Airbus) has large-scale structures grown from ALM-enabled (additive layer manufacturing) manufacturing systems on our technology road maps. The prospect is growing a full-sized airliner wing, which we have earmarked for some time beyond 2020. This is not a far-fetched notion. Go to [Airbus wing-making facility] Broughton in North Wales and you’ll see 35 meter-long gantry machining center with CNC (computer numerical controlled machine tools) heads for bespoke machining of whole wing skins. Change the machining head to a laser-deposition head and you can start to see the possibilities straight away.
Airbus has 20 research and development projects that are working towards the goal of printing all the parts of an entire airplane.
EADS Utopium - additive manufacturing with carbon nanotubes
Reeves envisages some even more fundamental advances over the next decade. ’At the moment we tend to manufacture parts in a single material,’ he said. ’But we’ll start to see functionality embedded into parts: electric tracks, optical tracks, different materials with different strain characteristics and maybe even sensors printed into parts as they are built.’ Displacing multiple manufacturing operations in this way will, he believes, make additive processes even more cost-effective.
Research around this is currently focused on polymer components, Johns explained. ’Today’s polymers used in ALM are low modulus; you wouldn’t want to put them on an aircraft,’ he said. ’A lot of our research development is into high-performing polymers such as PEEK and that gives us the opportunity to introduce things such as carbon-nanotube technology.’
The EADS team has already succeeded in growing aligned nanotubes within ALM structures, Johns said. ’We have a lot of IP developing around a material we’ve called Utopium,’
The last reports from this EADS Innovation works project were from the end of 2013.
SOURCES - Journal of Cleaner Production, Northwestern University,Technology Review, MIT