Airplanes are expensive to build, and relatively few are made each month. A Boeing press release from January touts the company has a seven-year order backlog for the Boeing 737, and is increasing production of the model to 52 airplanes each month.
"So that means that all the parts that you need [are] made in not very large numbers," said Tony Rollet, co-director of Carnegie Mellon University's Next Manufacturing Center. "Every now and again some older aircraft have to be repaired, and you need some piece of aluminum or titanium, and maybe it's not sitting there on the shelf."
NASA's aviation arm has commissioned researchers at Carnegie Mellon University, the University of Pittsburgh and other institutions to improve the process of 3-D printing airplane parts. Additive manufacturing, or 3-D printing, is the new big thing for aviation because of its flexibility, according to Rollet.
"It allows you to make things of pretty nearly arbitrary shape in quite a wide range of materials," Rollet said.
Rollet said they won't be printing whole wings, for example, because they're so huge. But they can 3-D print smaller components, like a part of a gas turbine engine. However, one of the challenges is that additive manufacturing for aviation is so new that the process hasn't been standardized.
"We lack really well-established ways to say, we know that this printer is doing its job properly," Rollet said. "And we know that Printer No. 1 is doing the same as Printer No. 11."
Rollet's team will ultimately work with the aviation industry to develop standards for 3-D printing parts.