Maintenance and interiors aircraft giant Lufthansa Technik is exploring 3D printing at greater depths, hoping to take its customers to the heights they’re accustomed to. A team at Lufthansa Technik made a titanium LPBF latch to replace a damaged polymer one. Usually, in 3D printed MRO, we try to go the other way, implementing lighter-weight, cheaper polymer parts in place of metal ones. In this case, a specific latch kept breaking.
Any time parts break on aircraft, the resulting repair can be costly. It could delay a flight, or a plane may actually have to be unused for a while for repairs. Meanwhile, not doing this may expose safety issues or make a classy airliner look dingy. Even if a metal 3D printed component is much more expensive than a polymer alternative, making it more durable may solve a lot of downtime and repairs, saving a lot of money in the end. And customer experience-wise, for the airline, interruptions and a reduction in the customer experience will bring further advantages. In this case, the part was not available for purchase, expediting the need for a solution.
The new part was made in Ti6Al4V in an EN 9100 process using Technik’s EASA Part 21. G and 21. J certification, while the part was a latch for a roller shutter. The part in question is in use on the A330, A340, and A380. The latch inside the roller would wear out and malfunction, requiring the entire roller shutter to be replaced. The supplier also wouldn’t allow Lufthansa Technik to buy the replacement component on its own. By making a replacement part, the entire shutter would last longer, while if it did break in the future, the company could just use a new printed part rather than buy a shutter. Lufthansa can do this because of the company’s ability to self-certify.
Project Engineer at Lufthansa Technik David Rudolz stated,
“The original part was an injection-molded polymer component with a complex geometry. It was immediately identified as an ideal candidate for metal additive manufacturing.”
“There’s been a strong partnership between Materialise and Lufthansa Technik for many years. Materialise is one of our preferred partners and was our first choice for this project.”
3D printed titanium latch developed for Lufthansa Technik. Image courtesy of Materialise.
Aviation MRO has significant potential. Because repairs are expensive, the cost of quality is very high, buy-to-fly is good, and the ancillary cost of aircraft not moving is so high that the business case for these parts is very high. I like the fact that Lufthansa is using its deep design and certification expertise while relying on a service to print its parts. This would reduce their need to have all kinds of printers for all kinds of parts that they could need. Lufthansa could outsource all the production and keep its operation relatively lean. Over time, they could decide to produce Ultem for aircraft interiors in-house, for example, without having to invest in metals. Many large firms buy their own machines too early on. It’s better to find out whether this makes sense to print in-house at all, and, if it does, which materials make sense. Then you could decide to buy a printer and buy the right one too.
As we’ve seen through our articles, aircraft MRO is advancing. Companies such as Air New Zealand make metal components with partners; Lufthansa uses FDM; GE is, of course, doing engine MRO with additive; AM Craft is offering this as a service to the likes of Finnair and has picked up investment from Stratasys. The path to making certified aircraft parts is a torturous one, and with good reason. We need the quality standards to be excessively good in this area. But for firms that have successfully made it work, aviation MRO may be a solid long-term business with a great business case.