Make it so

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Additive manufacturing and aerospace. It is hard to find more exciting topics for discussion in the plastics processing universe - and just like the rocket ship that soars out of the earth's atmosphere, the fact these two worlds are now colliding is not only broadening horizons, but sailing past them into vastness.

Saudi Arabian chemicals giant SABIC and Israel-headquartered additive manufacturing heavyweight champion Stratasys have been embarking on major 3D printing projects in the aerospace sphere - both together and separately - exploring just how this innovative technology can take aerospace production even further with the help of engineering plastics and some of the most fascinating manufacturing technologies in existence.

SABIC ULTEM 9085, a strong, lightweight, flame-retardant resin, coupled with Stratasys' FDM (fused deposition modelling) technology has addressed one of the biggest challenges facing manufacturing for aerospace - the ability to produce small volume parts quickly and cost effectively. SABIC and Stratasys have been working together on perfecting the combination of ULTEM 9085 and FDM since 2012, when they partnered on a project with Taylor-Deal Aviation in Texas to create specialty fluid and air handling parts - slashing production time down from weeks to hours.

It's not a dream, it's a fact

Additive manufactured ULTEM 9085 affords greater design flexibility, cheaper low production runs and accelerated cycle times in compliance with Federal Aviation Administration (FAA) and OEM flame smoke toxicity regulations. The material provides a high strength-to-weight ratio and high thermal resistance, stiffness and chemical resistance.

"Aerospace parts not only have to ensure standard levels of reliability and accuracy, but we also have to be able to provide aerospace companies with extremely detailed information on every part of the process of manufacturing this particular material," explained John Jones, Stratasys Materials Business Manager EMEA.

"But now, we're not just talking about using ULTEM 9085 for prototypes but real in-flight parts. There are planes out there containing Stratasys FDM parts. It's not a dream, it's a fact - but it's taken a number of years of research approval and Stratasys fulfilling the needs of the aerospace company and them ensuring the materials meet their high criteria."

ULTEM 9085 has been certified to Airbus material specification and the resin has been used to additive manufacture more than 1,000 flight parts in the A350 XWB aircraft fleet, delivered in December 2014. The 3D-printed parts replaced traditionally-manufactured parts to increase supply chain flexibility, allowing Airbus to meet its delivery deadline.

"It's almost custom manufacturing," Jones noted. "We're talking tens of parts in terms of each manufacturing run and you might not see those parts because they’re behind the panels, but one of the benefits of additive manufacturing is recognising the ease of manufacture of any geometry so they no longer have to consider the restraints of designing a part."

Efficiency and intelligence

This in turn aids OEMs in succeeding in producing parts that are more lightweight.

Engineering Resins Communications Leader at SABIC Susan LeBourdais added that ULTEM 9085 combined with additive manufacturing technology is making metal replacement development easier for OEMs than trying to upgrade a metal component to a traditionally-manufactured plastic replacement.

"For very valid safety reasons, any transition from metal to plastics has to go through a very intense certification process to ensure it will perform, and the benchmark for the FAA, for example, is it has to meet the bar set by the incumbent material in the incumbent part," she explained. "So to make those translations from metal to plastic the OEM needs to re-design, re-certify, re-tool ... that's a very labour intensive and time-intensive process. But if you bring additive manufacturing into that equation all of a sudden you see designs in place more rapidly."

Global Marketing Director at SABIC Kim Choate added: "It makes the whole cycle faster and less expensive. But thanks to additive manufacturing, now, instead of having a component made of many different connections, I can make just one product and it's lighter and more efficient. ULTEM 9085 has the right mechanical strength and performance and a lot of the OEMs are actually converting and are running production for those and other parts as well in 3D printing.

"3D printing has allowed us to go from many parts to one part. It’s lighter, so saves the airline fuel, making savings for their customers, and they are able to [produce that part] quickly and cost-effectively, bringing operational costs down as well. There's no other option to make these parts this way. Technology continues to evolve ... You know you're not at the point we're going to print cars every day but we're at least at a point of proving those concepts have the potential."

Live long and … prototype

Despite additive manufacturing's gradual assimilation into the manufacturing supply chain, the technology's roots in prototyping are just as relevant now as they were 20 years ago.

"Rapid prototyping has changed the way we interact with customers," Choate explained. "I work on the high performance side of the business and it’s very expensive to make a conversion. Sometimes it takes one or two years just to go from a design to a prototype. It would take me six months to go from a specialised tool I could produce 10 parts on to see whether it works or not, to now getting a phone call two weeks later to say the part is on that customer's desk. That's changed the way we collaborate together and it speeds up the evolution of technology.

"In aerospace there's a backlog of everything," he continued, "so anywhere in the value chain you can help speed things up, letting us play with designs and do things in a way that is lighter

while making the cost of a total solution cheaper to the end customers, is a good thing. We can see that 3D printing is helping us to redefine how things look and how we come up with ideas. It's fun. [From the perspective of] an engineer, any time you can completely change the way you do business is always a wonderful experience."

For hidden parts, Choate and LeBourdais explained, additive manufacturing is especially attractive. Fluid handling parts are essential to the running of a plane, but they do not require the secondary processing to make them aesthetically pleasing and for low-volume, end-of-life manufacturing in particular, the cost and materials savings benefits are huge.

"The nice thing about aerospace is that you're helping everyone," Choate smiled. "So the customer gets a cheaper ticket, the OEM gets a lower operating cost, the OEM gets to make things faster with fewer parts and less risk with less wastage."

The customisation game

But it is not only the hidden components where Stratasys and SABIC see potential for 3D printing in aerospace, both have visions for additive manufacturing spreading the trend for customisation into aircraft in the years to come.

"Airlines are on a major trend to make the interior of the plane match their brands, so they want everything to be customised," Choate stated. "They've made planes one way for 40 years but now we can go from designer's sketch to making that concept a reality and make what we can imagine real. Now we have transparent materials and other materials beyond 3D printing like composites technology and all of a sudden we can have OEMs produce a truly customised environment for an airline - so when you get on a plane, it doesn't look the same as the last plane you boarded. It will start in business class and work its way through the cabin - and that's fun because we'll have more designers coming into work smiling."

"There's definitely a private industry where the [customisation trend] will see personal jets given very personal features," Jones said. "These Airbus-approved materials would also be suitable for non-critical parts on private jets and there is a real market for this with huge potential for additive manufacturing."

Aerospace has found the benefits of using additive manufacturing not only with FDM but also PolyJet technology for prototypes and non-in-flight parts, which Stratasys showcased at its vast stand at Euromold 2014. A cross section of an aircraft cabin was used as a demonstration model of how far you can take 3D printing when producing the interior of an aeroplane - and not just air ducts.

The cabin interior employed a combination of FDM and PolyJet 3D printing techniques for prototypes of various seat parts, manufacturing tools for sand casting patterns for seat bases, and end use parts such as the sidewall upper skin, electrical clips and air ducts. The armrests were additive manufactured using digital ABS to demonstrate how 3D printing can minimise the amount of material needed to produce a component that is both sturdy and lightweight.

"You can take that one step further," Jones said, "using the unique ability of the PolyJet to print a rigid part and simultaneously print a rubberlike material onto that part, so you could have an arm rest with soft-touch features that is also very, very light."

3D printing has lift-off

Now ULTEM 9085 3D-printed parts are airborne on Airbus planes, they are one step closer to making it into other aeroplanes, Boeing aircraft for example, and Stratasys has even watched 3D printed parts fly into space.

Rocket manufacturer United Launch Alliance (ULA) has progressed from using additive manufacturing in prototyping, to producing flight hardware on two Fortus 900mc 3D Production Systems from Stratasys, namely the Environmental Control System (ECS) duct on its Atlas C. The ECS duct - which is also made of ULTEM 9085 - is critical to the launch countdown sequence and delivering nitrogen to sensitive electronic components within the rocket booster. The 3D-printed design has cut the ECS duct down from an assembly of 140 parts to just 16, resulting in an installation time that cost 57 per cent less per part.

This breakthrough for ULTEM 9085 and for 3D printing brings the concept of 3D printing parts in space to replace broken components or to create tools the crew do not already have closer to reality.

"I'm sure there's a lot of work going on in the background with these things," Jones mused. "Gravity I'm sure has its challenges with 3D printing but there are problems that could be overcome with having a 3D printer on a space station, or at a military base or desert for that matter. I don't think it's achievable yet, but the idea of taking raw materials and a printer for spare parts is interesting and we'll see it in the not so distant future."

Choate added that the possibility for thermoset materials that can be recycled - perhaps on-site on a space station or at a remote site - means the materials could be ground down and re-printed, resulting in a continuing supply of material.

Where no man has gone before

Whether looking at the amazing things ULTEM 9085 is achieving in aerospace now, or meditating over how it could be used in the future, there is no doubt that additive manufacturing for aerospace presents a brave new world.

Jones said the excitement of what is now possible is thrilling.

"The breadth of industries we work with is phenomenal but the thrilling aspect on a commercial sense is there's a huge potential for it out there and we're only scratching the surface. The faster the machines get, the materials that are already available like ULTEM 9085 will work for even more applications. That's what gets me excited. Opportunities around every corner," he mused.

"We predicted solar panels 30 years before we started making them. 3D is the same as solar, you can imagine how it will look in the future," said Choate.

"But ultimately helping customers win is the funnest part of the job," LeBourdais added.

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