3D printing could revolutionise aerospace manufacturing as customers demand lower volumes and greater customisation, according to BAE Systems.
The British defence contractor made the news at the start of the year after a 3D-printed metal camera bracket it created was flown on-board an RAF Tornado fighter jet for the first time.
Now the firm is ramping up its 3D printing – otherwise known as additive manufacturing – operations with the goal of a fully developed production system by 2017, as it seeks to cut development costs and respond to demand for bespoke parts from customers.
The firm is currently experimenting with various technologies at its Tornado support and maintenance centre at RAF Marham and has integrated them with both 3D-scanning technology and computer-aided design (CAD) software to create a complete production suite.
“3D printing and additive manufacturing is one of the key technologies that we are starting to use in quite a powerful manner in terms of supporting aircraft,” said John Dunstan, head of agile product development at BAE Military Air and Information (MAI), at an event at Farnborough Airshow today. “We are starting to see real cost savings for both ourselves and our customers.”
The key advantages of the process are its speed and cost-savings at low volumes. Lead times for production using conventional manufacturing methods can run into months and it developing production tools for just a handful of components is highly inefficient.
When it was discovered that ground crews were accidentally damaging new radio antennae’s on the Tornados at RAF Marham the BAE team designed protective plastic covers in a matter of weeks that take a day to build using fuse-deposition modelling and cost less than £100 a unit, saving £1.2m in manufacturing costs over four years.
But the real goal for BAE is to perfect the process of manufacturing large metal structures for aircraft using additive methods. The company is working with Cranfield University on a specific kind of 3D printing known as ‘wire and arc additive manufacture’ and last year they used it to build a 1.2m long structural component known as a spar section from titanium.
The process of designing and manufacturing such a part using traditional forging techniques would have required a lead time of 12 to 18 months, according to Mike Murray, head of airframe integration at BAE MAI, but using additive manufacturing the part was designed in a couple of weeks and printed in 37 hours. “We really want to show engineers the art of the possible,” added Murray.
But while creating small batches of bespoke parts can be more efficient using such process, they still cannot match the volumes of mass production. Altringham-based PI Castings uses 3D printing to create prototype components for its customers, but when it comes to full scale runs they rely on investment casting technology.
“I don’t see it as a threat at all. They’re normally only small batch runs, because the time spent on a couple of parts, you could have had a production tool made,” said sales engineer Andrew Smith.
“I know these machines are getting cleverer and cleverer, but when I talk to people who run them they do say the cost of parts is probably never going to fall in line with what customers want.”
While mass production may be out of reach for current technology, BAE has high hopes for the future of 3D printing. Earlier this month it revealed a collection of ‘drawing board’ technologiesdreamt up by experts at the company’s R&D team that it says could be incorporated in military and civil aircraft by 2040, including 3D printers that could print entire unmanned aerial vehicles.
Futurist and engineering manager Nick Colosimo who lead the work says that as the range of materials available for additive manufacturing grows, as more complex components become feasible and as processes become faster then this kind of fully integrated production system becomes entirely feasible.
“We expect an evolution,” he said. “Eventually you may even see mobile 3D printing systems you could store on the back of trucks and drive to the point of need to get stuff when and where you need it.”
While he concedes the process still cannot match the volumes of mass production, he says heavy plant volume manufacturing is likely to be augmented by additive processes in any future aerospace industry.
“It provides adaptability and, I think, responsiveness. What you’re doing is taking out the whole logistics chain, whether you’re building parts at the home of the customer or out at an operating base.”
One technology that could make mass production with additive manufacturing a possibility is the FACTUM machine created earlier this year by University of Sheffield spin-out FaraPack Polymers and researchers at the University of Loughborough, which uses high speed sintering to build finger-sized parts in roughly 10 seconds.
The machine uses inkjet print heads to lay down a binding agent in a bed of powdered material before infrared heating lamps sinter the material together. Infrared heating can affect a larger area more quickly than traditional lasers, speeding the process up.
“That is a significant change in the way sintered parts are manufactured,” said BAE’s Murray. “That starts to make it competitive with injection moulding as you’re looking at a significantly faster process, anywhere from 50 to 100 times faster.”
The Aerospace Technology Institute (ATI), a £2bn joint venture between the UK Government and major aerospace players that started work earlier this year to promote and develop UK aerospace technology, also has high hopes for additive manufacturing.
But according to Simon Masters, lead technologists for aerospace at the Technology Strategy Board, which is the ATI’s Government delivery partner, the consistency of the process may need to be proven before the technology can have a real impact.
“One of the challenges is repeatability – can you manufacture 100 components at the same standard of quality?” he said. “The powders, or whatever they are using to build up these structures, these materials are new and relatively unproven in aerospace. Some of the requirements for rigorous quality control you need for aircraft are a challenge.”
And according to BAE’s Murray a certain amount of evangelising needs to be done before the engineers warm to the technology.
While it allows engineers to design in a more “organic” way – of particular interest to aerospace engineers is the ability to optimise the geometry of the components they make to save on weight – many CAD packages are not optimised for this kind of approach and it doesn’t always come naturally to engineers.
“Engineers have been brought up in a subtractive environment. All of a sudden you are telling them to grow and it’s a very different way of manufacturing. And if you just grow in exactly the same way you machine then there’s no benefit,” said Murray.
“The costs are the materials and time on the machine. The lighter you make it the cheaper it is. It’s very hard to get engineers to believe it, but it’s a fact.”
Source: Engineering and Technology Magazine