Adding value with 3D printing

The Airbus A350 XWB contains a myriad of manufacturing innovations. A streamlined production with its optimised workflow, a highly-integrated component supply chain enabling fully equipped modules to be supplied. But what will have the greatest impact on future aerospace manufacturing is the growth of additive layer manufacturing (ALM), or as it is commonly referred to, 3D printing. Leading that evolution is the A350 XWB.

3D printed parts are already used by Airbus from its widebody A350 XWB to its single-aisle A320neo and the cornerstone A300/A310 family. For example, some 2,700 plastic parts have been produced by ALM for the A350 XWB programme, with Airbus also working with the European Aviation Safety Agency (EASA) to qualify titanium components produced with 3D printing technology.

“3D printing is being progressively integrated into new design and manufacturing in the supply chain, starting small but steadfastly in the fields of prototyping, tooling and on-demand production,” explains Peter Sander, head of emerging technologies at Airbus. “Airbus has teamed up with major 3D printing stakeholders to cover the process end-to-end, ensuring the production of certifiable structural components based on consistent tested material properties and meeting the requirements of a rigorous certification process.

“3D printing makes it simpler to produce very complex shapes, therefore parts designed for and manufactured by ALM can have a natural and topologically optimised shape, which would be impossible if producing them from a solid block of material. Such parts are significantly lighter, faster to produce and ultimately much less expensive than conventional ones.”

From humble beginnings

The journey for Airbus began with a small plastic crew seat panel on an A310 operated by Canada’s Air Transat. The lead-time for such a part can be as little as one day if the component is based on an existing design, while redesigned parts can be produced in less than two weeks. From there the momentum has built.

Two years ago, it qualified Stratasys’ ULTEM 9085 3D printing material to produce flight parts for its A350 XWB aircraft, and late last year Airbus announced it was standardising on this resin using Stratasys’ Fused Deposition Modelling (FDM) based additive manufacturing solutions for its components.

FDM is used to generate plastic parts, 3D objects are built by printing fine layers of liquefied building material filament onto a building platform that fuse with the layer beneath. At the same time, a support material is printed to allow printing of the building material further up the object of features that hang from the main structure. The build platform moves down incrementally to print the following layer. Once finished, the printed support parts are removed.

At that time, Airbus produced more than 1,000 parts that they used for early deliveries of the aircraft as a missed part production approach. At present this technology is used primarily as a supply chain tool but it is in the move to series production parts that Airbus will gain the full advantages that 3D printing offers.

“I would say it is starting to hit that inflection point,” states Scott Sevcik, head of aerospace, automotive and defence at Stratasys. “It’s been inching towards serial production over the past three or four years and we have seen significant uptake in the types of applications and the ways that aerospace customers are using the technology on board aircraft.

“The benefit of moving into serial production parts is that it is your primary part; you can start designing for the technology. When we start moving to serial production, we’re talking about the opportunity to redesign and really take advantage of the technology, start consolidating whole assemblies into a single part, start designing with topology optimisation tools in order to lightweight the part and take as much material out as possible. So, that’s the real significance for us as we’re moving into production with Airbus.”

Challenges to greater use

There are two things slowing down broader adoption – certification and surface finish. “We have a technology that was originated as prototyping technology and that doesn’t really require a high degree of consistency in the mechanical properties of the parts that are being produced,” Sevcik adds. “When we talk about production, that’s our principal concern; we need to understand exactly what the properties of the part are going to be and they need to be very, very repeatable.

“That repeatability then lends itself to certification. If you can show that you have a repeatable process that’s consistently producing the same strong part, then that allows the FAA or EASA or any airworthiness authority to have confidence in the parts that are being produced through the technology.”

When it comes to surface finish, it’s the size of that bead of material that creates the surface of the part. If you put down a lot of material very fast, that will create a very rough, bumpy part. On the flip side if the aim is a fine resolution then it will take a very long time to produce that part. “The trade-off in the workflow between speed and surface finish has been a challenge in the adoption in the industry,” Sevcik continues. “That’s another area that we’ve been working on quite substantially because we see a strong need for parts that are aesthetic, cosmetic parts for cabin interiors to enable customers to offer customised interior experiences. That can all be done very cost effectively with 3D printing, provided there’s a means to provide a cosmetic surface.”

Future prospects

With the Stratasys’ technology, the initial applications that Airbus have adopted have all been non-critical parts for the cabin interior. But Sevcik reports that there is strong interest from several aerospace companies in using the technology for structural applications. “It’s been a continual process of working on the right materials for those customers to ensure that we can meet the needs of the airworthiness authorities as we move into structural applications,” he says.

For its part, Airbus is looking at the entire aircraft: cabin, system and structural components, as well as manufacturing and tooling. It will also play a major role in the production of spare parts. “In the coming years 3D printing could potentially account for thousands of aircraft and ground support equipment components,” Sander says.

3D printed airworthiness certified parts are already common on the A350 programme and the list of parts proposed as candidates for 3D printing is constantly growing. “As technology develops we may one day see the first entire aircraft built using ALM,” Sander concludes.

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