Making future aircraft wings through composites manufacturing
Image credit: Dezzor | Dreamstime
The UK’s National Composites Centre (NCC) in Bristol has opened a new research and development facility that aims to harness the power of new digital technologies – one of which has the potential to build the aircraft wings of the future.
Back in December 2018, the NCC had secured funding for the £36.7m iCAP (Digital Capability Acquisition) programme, under which ten new technologies, tailor-made to the NCC’s specifications, were installed within the facility in order to speed the development of new processes for all forms of composite manufacturing.
Funded, in part, by the Aerospace Technology Institute (ATI), in collaboration with the Local Enterprise Partnership and the High-Value Manufacturing Catapult, the programme has brought composites into the digital age, increased production rates and quality while improving efficiency and reducing cost, its members have said.
Two years on, Peter Giddings, chief engineer of the iCAP programme at the NCC, says the experience has been brilliant. “It’s been really developmental – both as a business where we were a good research centre, but a small one,” he told E&T, “and we’ve had a massive amount of faith from the funding bodies, and support from them, and some really strong relationships with customers.”
The global market for composites is predicted to be worth $105.8bn (£82.8bn) in 2020 and growing at 6.5 per year. In the UK alone, the value of composites is expected to reach £12.5bn by 2030 as manufacturers seek to make products lighter, stronger and more durable. According to the NCC, the Bristol-based centre ensures that Britain is at the forefront of this fast-growing sector.
“With the most advanced manufacturing facility in Europe, we truly have an unrivalled world-class capability,” said Richard Oldfield, chief executive of the NCC when launching this new phase. “The investment in 10 new world-leading composites capabilities will enable us to develop the wings and engines for the aircraft of the future, work on technologies that will define the way we produce and store energy and transform the way we build infrastructure.”
As Oldfield noted, aerospace is a significant driver of demand, with operators looking to replace an ageing global fleet of passenger and freight planes with more fuel-efficient aircraft, compliant with increasingly stringent noise and emissions legislation.
Reducing the weight of aircraft wings is key, so composites will play an essential role in delivering the performance gains required whilst maintaining safety standards, manufacturing experts have said. Meanwhile, with the current use of labour-intensive techniques, many manufacturers can only make around six pairs of wings per month, whereas the market requires 100 pairs per month. The NCC says it has a new machine which meets this demand.
“The next plane that is coming, and the next plane they [Airbus and Boeing] would need are the smaller, regional planes such as the A320. And they need wings for those” Giddings explains. “But they need 60 of those [planes] a month, every month, and some months they need at least 100 of them a month. The composites industry, however, has no process which is fast enough to meet that demand.”
However, the NCC’s partners within the aerospace industry had given them the challenge of creating a method of making this process ten times faster – wanting them to work with dry fabrics to infuse the resin at a later stage.
Within the facility, the NCC has installed two huge industrial robots that automate the wing production process. Weighing 45,000kg and 24,000kg respectively, the robots measure, cut, lift and place pieces of carbon fibre fabric (‘plies’) with millimetric accuracy. They can also lay 5m wide strips of composite material, up to 20m long, in one precise movement.
According to the NCC, this machine, known as the High Rate Deposition Cell, can cut the number of fabric components required from approximately 100,000 to just 150 and reduces wing-build time from one week to one day. In the process, two huge robots, both 7m high, run up and down a 26m track, positioning them to within 0.2mm accuracy. NCC believes this has the potential to revolutionise aircraft production.
A modern wing is made from composite material – carbon fibre fabrics moulded and infused with resin. The ways in which these materials are placed, however, varies depending on the job each part has to do. The NCC describe it like tailoring a suit – only on a vastly bigger scale.
To make the wing, design engineers use digital modelling and simulation, analysing thousands of possible configurations to create a digital pattern book of the layers or ‘plies’. For a single wing skin with 150 plies, there could be up to 14,000 possible combinations of cutting and laying, according to the NCC.
Next, ‘The Sequencer’, unique software developed by NCC engineers, creates the instruction manual. Then the carbon-fibre fabric is laid out on a 20m-long table and cut into shape with an ultrasonic knife.
Once the pieces of fabric have been cut into a shape they can be filed in drawers or directly placed onto a tool in two ways. The FibreFORM tool (see above) has 270 suction cups mounted on flexible ‘spline’, each able to position and provide suction on command. It can pick up a piece of material and carefully manipulate it into a 3D shape and then place it on a specially shaped tool and repeat the process. Its FibreROLL tool (pictured below) then rolls up the ply and lays it across the shaped tool surface.
“What we’ve done – working with our suppliers over quite a few years – is that we’ve developed a system which will take a wide roll of the fabric of carbon fibre, cut it into the right shape [which can be anything between up to 2.5m wide and 20m long],” Giddings summarises. However, he added that this system has the capability to do 5m wide and 20m long, but stressed that no one in the world makes fabric that big yet. “If this [system] works, they will,” he said, therefore meaning the NCC could make A320 wings with a single piece of fabric.
Giddings said this process may look simple, but to execute it remains a challenge. “These fabrics are so delicate that if you gently place your hand on them, you leave a handprint on them,” he explains. “People aren’t really able to lift them, as they deform and sag as they are incredibly flexible.”
He also told E&T that, currently, these high deposition cell robots have a human operator always on standby as the team at NCC are trying to look into how they can fully automate these processes. “The deal with automation is that you can’t automate what you don’t fully understand,” he explains. “What you can do alternatively is automate the stages of the process you do understand robustly, for example, the ply cutting.”
He added that some of the elements around inspection, however, remain a challenge in fully automating the process. But the NCC has a couple of other projects that are developing techniques around this – training their engineers in analysing that data to try to create those rules, for example.
The NCC has also rethought how manufacturers test completed composite parts for quality control. This is currently a slow and expensive process, which typically involves the destruction of the part being examined.
In response to this issue, NCC engineers have commissioned two 3m-high robots that work in unison, on either side of the component, to beam ultrasound down high-pressure water jets. The system then measures the time taken for sound to travel through the part, alerting operators to any anomalies. This, therefore, ensures the components meet safety regulations.
Other technologies within the facility include a giant circular Braider (see below), the largest of its kind in Europe, which automatically weaves up to 288 individual strands of high-strength carbon fibre to create hollow 3D shapes (or geometries), for products such as pipes or aircraft propellers.
The only two-ring braider in the UK, the NCC braider (pictured above) comprises 288 and 192 spools and is more than twice as flexible as a single-ring braider. The two rings and a 10m long gantry enable its operators to braid complex circular, rectangular and convex sections, in the widest possible range from 50mm to 800mm equivalent diameter. The braider is also capable of a very high deposition rate: up to 50kg/h.
The braider can create hollow straight parts such as tubes and tanks or complex cross-sections with curved profiles such as ducts, cones and horns. Also according to the NCC, its braider has a high rate production, high quality and repeatability, produces low material waste and has near-net-shape preforming among other benefits.
Meanwhile, the facility’s Overmoulder (see video below) shows how composite components can be mass-produced at rate. This would enable carmakers, for example, to use more of the technology in mainstream vehicles, making them lighter and more durable. These are key considerations given the long-term shift towards electrification and, beyond that, new models of shared ownership where cars will be expected to do ample mileages.
Regarding the process of the Overmoulder, a composite sheet is melted and formed, and then the thermoplastic polymer is injected over the surface in this highly automated process, that can achieve rapid cycle production of less than 5 minutes with potential for under 60-second cycle times for some parts. According to the NCC, this process combines the structural benefit of a long-fibre reinforced composite sheet with the speed and geometric complexity of injection moulding.
“We can learn lessons here [from the technologies] and transfer them directly out in industry, but we will do it on a machine that is way more flexible,” Giddings explains. “Our flexibility means that our machines look quite different from industrial machines. We’ve developed all that knowledge to be able to say that we’ve learnt a lesson, this week, and with these parameters, we can tether to your [other industry] machine and help you deploy it.”
The NCC aspires to become more sustainable in its manufacturing process, and Giddings believes that making such processes automated will help limit a manufacturer's climate impact. “The best way to mitigate the impact from climate is to make fewer mistakes [in the process],” he explains. “Ultimately for many manufacturing processes, you have to create a lot of force, making things quite hot; both of those require a lot of energy – and you don’t want to be doing that again.”
In an automated process, however, Giddings thinks that manufacturers have a better chance of getting the process right the first time around, which therefore means they won’t scrap components. “There’s nothing less efficient than deciding to put something in the bin,” he adds. “That’s a big drive for us.”
Giddings also said the NCC is looking at ways to be less energy-intensive in its manufacturing process, for example, in its industrial oven. “We’re trying to tune where we put heat into different parts of a structure,” he explains. “So if something has a hotter material, and it’s going to be quite slow to heat up, we can concentrate the energy in that area, whereas for other parts of the component where it doesn’t need that much heat to make it the same temperature, we don’t put that much heat into it.” Therefore, they are balancing off the energy they use to achieve the result and end product they need – not overheating or underheating certain parts.
Furthermore, Giddings said some of the processes the NCC use are suitable for the reuse of recycled products. “The equipment is enabled to take recycled materials wherever possible,” he says. “We’ve got some other big programmes in the business looking at how we recycle materials.”
He also elaborated on how much impact the manufacturing process of planes has on the climate. “The energy we use in making an aeroplane is a couple of per cent of the energy that the plane uses through its life,” he explains. “So even if we halved our energy input, and halved our carbon intensity in the manufacturing process, we would make a tiny difference to the overall carbon impact of having the aircraft in service.” So what the NCC is focusing on, Giddings says, is making sure plane-makers don’t increase their carbon intensity in manufacturing but are currently doing things that will reduce their carbon intensity.
Having already partnered with world-class innovators such as Airbus, Rolls-Royce, GKN and Williams Advanced Engineering, the centre is now establishing more partnerships across the world, securing major new projects from IHI of Japan and Vestas from Denmark. Furthermore, the team at NCC believe that the centre’s new digital capabilities will further enhance its international position as the global reference for composites manufacturing.
At an event at the NCC on 28 February, it was announced that the NCC and other businesses in the region around Bristol are now embarking on another programme, which aims to put the West of England on the map for manufacturing and aspires to revolutionise the region’s advanced digital engineering sector.
At the end of January, the West of England Combined Authority (WECA) awarded £5m to the new Centre for Digital Engineering Technology & Innovation (DETI) – to match-fund £5m from West of England businesses who are at the forefront of the manufacturing industry. It is a flagship investment which supports the region’s Local Industrial Strategy and is one of the building blocks in creating a Global Centre of Innovation Excellence – bringing together innovative expertise to solve future challenges.
DETI is a research, innovation and skills initiative – a collaboration of industry and academic partners led by the NCC – which sets out to develop and accelerate digital engineering across multiple industry sectors to benefit future generations of engineers and engineering products, and to help tackle global challenges.
West of England Mayor, Tim Bowles said: “Our region is a global leader in high-value design and innovation, and we want to make sure we retain that position in the face of global competition. DETI will help us do that by putting the West of England at the forefront of the fourth industrial revolution and bring together the worlds of digital technology and advanced engineering.”
“DETI will be a nationally important centre, based in the West of England,” he added. “It will help secure the future of the aerospace and advanced manufacturing industries and is a key part of our Local Industrial Strategy ambition to strengthen cross-sectoral innovation and support our region’s ambition for clean and inclusive growth.”
The project will develop training courses related to advanced digital engineering, with the aim of increasing the skills and retraining those in the current workforce. It will also engage with schools, particularly in less affluent parts of the West of England, with the aim to reach 1,000 children and inspire them to pursue a career in digital engineering.
DETI is not a new building but will use existing facilities and assets at the NCC and another crucial partner in the collaboration, the Centre for Modelling and Simulation (CFMS) at the Bristol and Bath Science Park, to undertake its research, innovation and skills initiatives. It also aims to bring together the wealth of specialist expertise from around the region and harnesses it to maximise opportunities for a better future.
In a similar way to the iCAP programme, the project members will work with leading companies and support industry to reduce carbon emissions by producing better products – products that are lighter, more fuel-efficient and have less waste – through undertaking research and innovation in the virtual world.
“The world faces unprecedented challenges which will require step changes in how society uses resources. DETI will bring together leading companies and tech disruptors to create the design and digital engineering of the future. It will help cement the UK’s world-leading position as an engineering nation, helping to overcome the world’s most complex challenges,” said Oldfield.
“We have already engaged with a really diverse range of companies across the tech, design, creative and engineering sectors to create an exciting collaboration where skills collide.
“With this investment from WECA, matched by industry, we will spend the next two years building skills, creating jobs and making the West of England the go-to place for UK high value design and engineering – putting the region on the world stage as a globally significant engineering and tech area.”
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