Additively manufactured carbon fibre wing repair kit.
Bionic brackets, LEAP engines, smart parts; you would be hard pressed to find a high-value area in aerospace where additive potential remains untapped. But what about those crucial day-to-day applications that can mean the difference between an aircraft taking off or grounded on the tarmac?
The majority of today’s modern aircraft wings are manufactured with carbon fibre thanks to the composite materials’ strong and lightweight properties. Less weight means bigger fuel savings and reduced costs, but the complex make-up of carbon fibre also poses its own unique challenges for aircraft manufacturers.
For one well-known aircraft OEM, a key pain point was discovered in the repair of carbon fibre wings during build. When a wing became damaged, the repair process would require the manufacturer to take the wing offline and painstakingly sand the carbon fibre back to allow new material to be built up in its place. To do that, heat must be applied to the correct area to speed up the cure timescale, which often means relying on a “hit and miss” approach affecting the quality and lead time projections.
The manufacturer, based in the UK, turned to FDM Digital Solutions, a Burnley-based additive manufacturing engineering company specialising primarily in aerospace and automotive sectors, to come up with a solution that would guarantee cure times for carbon repair.
“Companies tend to have one massive jig, no matter how big or small the repair area is, it’s just not very efficient,” explains Tony Flanagan, Business Development Manager at FDM Digital. “This is a solution that allows people to be much more flexible and just focus on the repair that they actually need to do.”
Quick release clamp attaches to heat blower for repairs.
The solution was a new kit that would allow the manufacturer to direct heat to the appropriate area and improve overall repair quality.
“It ensures that they can carry on working around an area being repaired rather than having to stop the job and there’s no delay to the build schedule,” adds Matt White, AM Solutions Lead Design Engineer at FDM Digital.
Matt led the design of a new set of four applicators and a quick release clamp that could be attached to the heat blower and swapped out easily to enable any area on the wing to be cured within the correct timescale. HP’s Multi Jet Fusion (MJF) 4200 system and PA12 powder were selected for production chiefly due to the material’s high temperature resistance, essential to successfully curing the damaged areas.
Matt notes how MJF’s robust material properties, compared to an alternative like Ultem, and consolidation of manufacturing steps were key enablers in bringing this application to fruition. In fact, FDM says it is now utilising the technology to produce around 90% of its tools.
“We produce a lot of parts that are used in end-use applications such as checking fixtures,” Matt explained. “This is an everyday tool. Additive gives people the freedom to have something that they actually want rather than a machined item that’s not really what they need.”
A total of five toolkits are now out in the field across various sites and in addition to being shortlisted in last year’s TCT Awards, FDM says it has also received interest from a number of additional aerospace companies facing similar challenges in their maintenance, repair and overhaul operations.
Tony added: “We’ve got to the point now where major companies see an issue and even if they can’t think of what the solution might be, they recognise that additive manufacturing could be a solution.”
