Bionic design and advanced fabrication methods are the future of additive manufacturing
Designed with Nature
Four years ago, I had an epiphany at the 2013 Paris Air Show that additive manufacturing (AM) would disrupt the aerospace industry (AW&ST July 29, 2013, p. 10). At this year’s show at Le Bourget, it was clear that AM developments are already doing so.
, a leader in the field, last year purchased key European metal AM equipment suppliers Arcam and Concept Laser and this year stood up GE Additive, a new business focused on third-party equipment and services that it hopes will become its ninth major business unit. To demonstrate its independence, GE Additive had its own chalet in Paris. ’s facility in Auburn, Alabama, now has 28 machines working around the clock to 3D-print its famous Leap fuel nozzles, with much more to come. An astounding 35% of its new Advanced Turboprop Engine for the Denali will be 3D-printed. Moreover, last month GE announced it is developing the world’s largest laser-powered 3D printer capable of handling parts within a 1-m2 (10.8-ft.2) envelope—ideal for large-engine structural parts.
Germany, meanwhile, boasts several well-organized AM clusters with active involvement from industry, government and academia. Why? According to Klaus Mueller, an executive with Bionic Production GmbH, “Germany leads because of our two-tier education system, which produces motivated engineers and highly skilled, self-thinking technicians.” German suppliers—including EOS, SLM Solutions, Trumpf and Concept Laser—control approximately 70% of the metal AM equipment market. And local aerospace manufacturers such as, MTU and Liebherr are aggressively pursuing the technology. New AM developments from all of these companies were on display in Paris. AM is now a mainstay with German medical equipment suppliers and is gaining momentum in the country’s large automotive sector.
While the early focus of AM was on powder-bed processes and small, complex and static parts, the technique has moved into large structural parts. The motivation is to attack large “buy-to-fly” ratios—often in the double digits—for parts made from expensive materials like titanium. A 20-lb. finished part, for example, might require 200-300 lb. of titanium, which creates $4,000 or more of scrap titanium per part
Norsk Titanium developed a process in which wire is melted in a cloud of argon gas and rapidly built up in layers to a near-net-shape part that requires very little machine finishing, resulting in overall savings of up to 30% due to decreased waste and energy input. Norsk just qualified its first part for theand has dozens more in development. The company is nearing completion of a large AM facility in Plattsburgh, New York, to complement its facilities in Norway.
Another recent development is the emergence of “bionic design”—using designs found in nature. Bird bones and lily pads, for example, have impressive strength-to-weight ratios and cannot be made by traditional subtractive manufacturing techniques. Airbus thinks bionic design could someday reduce aerostructure weight 20-30% or more. It has evaluated applying bionic design to thousands of parts and printed more than 100 demonstrators.
The additive-bionic combination, which was not on the radar at Paris in 2013, is analogous to the introduction of composites four decades ago. Early composite aerostructure designs, dubbed “black aluminum,” looked like metallic aircraft. It took several decades for designs to catch up to the unique properties of composites. “The mental mindset of engineers is one of the biggest obstacles for AM—particularly with bionic design taking hold,” says Mueller. “OEMs need to educate their engineers now if they plan to use bionics—especially if they are going to compete for future programs like the  797 in the next decade.”
AM economics are moving in the right direction. Titanium powder was more than $500/lb. four years ago; it is now 60-80% cheaper, as volumes increase. Processing rates are also increasing: AM fabrication machines featured one laser several years ago; next-generation machines with six lasers are on the horizon.
Despite all the good news, economics and regulation remain major barriers to more widespread AM adoption. Recertifying parts for existing aircraft is particularly challenging, which is why clean-sheet aircraft such as the much-anticipated 797 are so important. Its likely 2025-26 service-entry date will provide a window for suppliers to unveil new AM-empowered designs. Suppliers that ignore this wave do so at their peril.
The progress of additive manufacturing since Paris 2013 is impressive. As Mueller reminds us, “For 3,000 years, we have gained trust in molded and casted parts. We are 25 years into additive manufacturing, and just five years into taking it seriously.”
Contributing columnist Kevin Michaels is president of AeroDynamic Advisory in Ann Arbor, Michigan.
The views expressed are not necessarily those of Aviation Week.