Airbus is targeting sometime beyond 2020 to be able to fabricate an airplane wing using additive manufacturing.
EADS (Airbus) has large-scale structures grown from ALM-enabled (additive layer manufacturing) manufacturing systems on our technology road maps. The prospect is growing a full-sized airliner wing, which we have earmarked for some time beyond 2020. This is not a far-fetched notion. Go to [Airbus wing-making facility] Broughton in North Wales and you’ll see 35 meter-long gantry machining center with CNC (computer numerical controlled machine tools) heads for bespoke machining of whole wing skins. Change the machining head to a laser-deposition head and you can start to see the possibilities straight away.
The turboprop was produced by RedEye on both Fortus 3D Production Systems and Dimension 3D Printers.
97% Cost Reduction; 83% Time Reduction
All 188 components were produced in 4 weeks and assembled in 2.5 weeks for a total production time of 6.5 weeks. Using conventional fabrication processes, such as machining and casting (with in-house and outside resources) a manufacturer would expect to spend 9 months or more producing a model like this. Using the FDM process in-house, a manufacturer could expect costs of roughly $25,000, versus an estimated $800,000 to $1 million for conventional processes. These numbers represent about a 97% reduction in production costs and 83% reduction in production time.
With conventional fabrication processes, the full gearbox assembly would be composed of metal. For this turbo-prop model, the components were produced from ABS plastic, which provided the strength to support the large, heavy gear assembly
Direct Metal Laser Sintering and Powder Melting for Making Metal Aircraft parts
While traditional ’subtractive’ manufacturing processes often remove up to 95 per cent of the raw material to arrive at a finished component, additive machines only use the material they need to make the part.
Additive manufacturing is often referred to as 3D printing, as it works in a similar way to a laser printer. The technique builds a solid object from a series of layers – each one printed directly on top of the previous one.
The raw material for ALM is a powder, which can be a thermopolymer or a metal; aluminium, stainless steel and titanium 6,4 are common. The printing chamber is generally heated to 10ºC below the melting point of the material – this ensures that the laser used to heat the powder can melt it quickly. For metals, this preheating eliminates residual stress from their processing, which can make them warp when welded.
The machines’ operating software cuts the CAD model of the workpiece into slices, whose thickness depends on the type of material used; CALM uses 0.1mm for polymers and 30 microns for metals. A blade mounted on a moving arm sweeps an even layer of the powder on top of the work surface inside the chamber, then a laser – generally around 200W – scans back and forth over the surface, melting the powder in the shape of the first layer. The work surface then drops by the thickness of the layer and another layer of powder is distributed over the surface.
Other ALM machines use electron beams rather than lasers, as they are capable of transmitting more energy and therefore melt the powder faster. These machines work at room temperature, again speeding up the process. However, they produce pieces with a rougher surface finish that requires further machining and residual stress isn’t eliminated.
Utopium – additive manufacturing with carbon nanotubes
Reeves envisages some even more fundamental advances over the next decade. ’At the moment we tend to manufacture parts in a single material,’ he said. ’But we’ll start to see functionality embedded into parts: electric tracks, optical tracks, different materials with different strain characteristics and maybe even sensors printed into parts as they are built.’ Displacing multiple manufacturing operations in this way will, he believes, make additive processes even more cost-effective.
Research around this is currently focused on polymer components, Johns explained. ’Today’s polymers used in ALM are low modulus; you wouldn’t want to put them on an aircraft,’ he said. ’A lot of our research development is into high-performing polymers such as PEEK and that gives us the opportunity to introduce things such as carbon-nanotube technology.’
The EADS team has already succeeded in growing aligned nanotubes within ALM structures, Johns said. ’We have a lot of IP developing around a material we’ve called Utopium,’ he said. ’This is future-fantastical stuff, but we could bring the values of carbon nanotubes into a material system, controlling the material structure and functionality. That would allow us to think about embedded sensor technologies. You could even use them for wing morphing.’
Redeye on demand case studies of large format prototyping
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