Arconic Talks Installing 3D-Printed Bracket on Series Production Commercial Airbus Airframe

Don Larsen, Arconic Vice President of R&D and General Manager of Advanced Manufacturing, discusses installing a 3D-printed titanium bracket on a commercial aircraft.

Airbus is on a mission to 3D print as much of an aircraft as possible and it’s pulling in a number of aerospace manufacturers and additive manufacturing (AM) companies into its massive project. Among them is Arconic (formerly Alcoa Inc.), which recently pulled off a first in 3D printing for aerospace when a 3D-printed titanium bracket was installed on the airframe of an Airbus A350 XWB commercial plane.

The Airbus A350 XWB will have a number of 3D-printed parts, including a titanium bracket produced by Arconic. (Image courtesy of Airbus.)

Unlike other metal and plastic 3D-printed parts flying on test planes, such as the Airbus A320 neo and A350 XWB test aircraft, this is the first to be installed on a series production Airbus commercial aircraft.

The 3D-printed titanium bracket assembly, produced by laser powder bed fusion and installed on a commercial A350 XWB aircraft. (Image courtesy of Airbus.)

To learn more about the project and Arconic’s overall history in AM for aerospace, ENGINEERING.com spoke with Don Larsen, Arconic Vice President of R&D and General Manager of Advanced.

3D Printing Airframe Parts

Right now, we’re in the early stages of adopting AM to produce end parts for use in aircraft. Numerous companies are making their marks, manufacturing engine components and pieces for inside the airplane cabin. Perhaps most famous in this regard is GE, which is 3D printing fuel nozzles for its LEAP engine.

During these early stages, we’re seeing a lot of step-by-step work being done in which businesses perform a battery of tests on a given 3D-printed part before it is installed on a test aircraft. The Arconic news is particularly interesting in that the part has been installed on the actual airframe of the A350 XWB. Given the structural nature of airframes, this may be a significant step toward producing structurally critical components for aircraft.

“What’s significant about making this component with 3D printing is the fact that it proves we can pass all of the qualification tollgates necessary to get a part on an airframe. For example, you have to pass many mechanical property tests, physical tests and chemical tests to make sure that you can make a repeatable part,” Larsen said. “Basically, the installation of this part on a series production aircraft paves the way so that Airbus can design other classes of 3D-printed parts, including structural and flight critical components.”

The bracket was printed on a laser powder bed fusion system for a few different reasons, Larsen said. Of prime importance was the buy-to-fly ratio made possible with the part. Titanium is an expensive metal. When a part is machined from a titanium block, for instance, there is a lot of wasted material. With AM, only a little more than the material needed goes into the manufacturing process.

“The part we’re replacing was machined from a titanium block, so you’re looking at buy-to-fly ratios of five to one or 10 to one,” Larsen said. “Whereas you’re looking at maybe 1.2 or 1.5 to 1 when you make it via AM.”

On top of that, using the laser powder bed fusion system, makes it possible to produce multiple parts very quickly. This will allow Arconic to produce batches of brackets for the A350 XWB. Under two additional agreements, the company will produce other titanium and nickel 3D printed parts for the A320 as well.

The bracket differs from previous metal 3D-printed parts installed on test planes in terms of use and composition. Not only is the bracket on the airframe and not within the engine, as is the case with the fuel nozzle from GE, the bracket also is made from titanium, a difficult metal to work with, according to Larsen.

“Frankly, it’s a little tougher to print a titanium part than it is cobalt and nickel parts. The material is much more sensitive to the atmosphere it’s printed in and the parameters you print it with,” Larsen said.

As we’ve heard from other industrial AM users, such as Aerojet Rocketdyne, Arconic couldn’t simply take a stock 3D printer and begin producing parts. Instead, there was significant tweaking to the machine and its parameters—such as laser power and the laser scan pattern—to ensure the proper quality and repeatability for the bracket and other components being made by the company.

“You can feed a perfect model into a 3D printer and when it’s done printing what comes out of the other side isn’t a perfect model dimensionally. As you print these parts, there are slight movements that occur that can cause issues with the dimensions,” Larsen said. “We do a lot of modeling and testing of prototype parts before we go into production and we understand how to manipulate the CAD file so that we can actually print a part that  when fully processed  meets our customer’s specifications.”

3D Printing at Arconic

In 2016, Arconic was formed as the result of a split, which saw the Alcoa Inc. parent company change its name to Arconic and take over the company’s Engineered Products and Solutions, Global Rolled Products, and Transportation and Construction Solutions businesses. Its bauxite, alumina and aluminum operations are now housed under a new company called Alcoa Corp.

Arconic has been involved with 3D printing nearly 20 years. Larsen recounted the experience when the first resin systems were installed at his site in Michigan. “It’s funny, I remember when the first 3D printing machine arrived during my first position in R&D at the research center in Whitehall,Mich. It was amazing to watch this laser scan the polymer and see this part rise out of the liquid. And, then, after all of that, to have this 3D-printed part.Previously to prototype   investment casting patterns, people had to lay up sheets of wax by hand and they took forever to make.”

The company began using the technology to make patterns for investment casting. Since then, Arconic has added AM capabilities in metal and plastic at sites in Texas, California, Georgia, Michigan and Pennsylvania, for 3D printing patterns, tools, molds, prototype and production hardware. In 2015, the company boosted its AM capabilities with the acquisition of RTI International Metals.

“With the acquisition of RTI in 2015 we gained significant additive manufacturing expertise,” Larsen said. “RTI had extensive experience in plastic production parts, as well as  experience on the metal AM side. So, it was a great segue for us to move from what we would call indirect AM into direct AM, directly making a part.”

With the RTI acquisition, Arconic added titanium 3D printing to its capabilities. Then, in 2016, the company opened a 3D printing metal powder production facility within the Arconic Technology Center. There, Arconic is producing proprietary titanium, nickel and aluminum powders optimized for aerospace 3D printing.

It’s also worth noting that Arconic owns one of the world’s largest hot isostatic pressing(HIP) complexes in aerospace. HIP is often necessary for strengthening 3D-printed metal parts during the post-production process.

While Arconic has a 100-year history in producing aluminum powders, it now has about 20 years of history in 3D printing. Combined, according to Larsen, this gives the company the expertise required for 3D printing quality and repeatable parts for aerospace.

The Future of Metal 3D Printing at Arconic

Through partners like Arconic, Airbus is laying the groundwork for a future in which 3D printing is a regular part of manufacturing end components for aircraft. However, there is still a lot of work to be done.

Larsen believes that some of the improvements made to metal AM will come from new technologies. “The machine technology will change such that we can probably print more parts per machine and do it faster. We might be able to eliminate putting supports on the parts as we print them,” he said.

The elimination of supports could be achieved from five-axis deposition technologies or the ability to produce removable supports, which has been demonstrated by XJet and Desktop Metal.

It’s also possible, according to Larsen, that machine manufacturers will become better about supplying the necessary parameters for ensuring quality and repeatability.

“I suppose that eventually the machine builders will get better at giving stock parameters out; however, you really need to have  deep metallurgical expertise and background to be able to get it right,” Larsen said.“If you look at Arconic, we’re experts in aluminum, titanium and nickel. There are subtleties in all of this that we address every day in production.There is an expertise we have that machine builders may never have—and that  allows us to develop parameters that are most likely superior to anybody else.”

Arconic will also be contributing to the future of metal 3D printing through its own AM technology. Arconic’s Ampliforge™, for instance, is a process that combines Sciaky’s large scale electron beam AM (EBAM) with forging. The process uses EBAM to quickly produce a near-net-shape before forging is applied to obtain the proper strength.

The Ampliforge process from Arconic. (Image courtesy of Arconic.)

“With the typical forging process, you might take six to eight steps to go from a billet to an actual part,” Larsen said. “With the Ampliforge process, we 3D print a preform and then forge it just once to achieve the same microstructure as a traditionally forged part. You’re going to save a lot of material and time. This will obviously allow much more efficient and less expensive production of parts.”

You can learn more about Arconic’s 3D printing capabilities at the company website.