Boeing 3D Printed Titanium Structure Elements
A Breakthrough in Aerospace Design & Production
The title is a slight variation on a famous line from Book of Numbers and more relevantly the Morse Code transmission in 1844 sent by Samuel FB Morse to open a telegraph line. Applied today, it heralds a significant advance in aerospace engineering, aircraft manufacturing and Part 25 certification.
The Boeing Company has incorporated 3-D-printed titanium parts as a structural element of the 787 Dreamliner. To produce these parts through innovative 3-D printing, Boeing selected Norsk Titanium AS, which will use its Rapid Plasma Deposition (RPD) process at a 67,000-square-foot factory with nine printers in Plattsburgh, New York.
The Norsk machine turns the raw titanium into pure wire. Then the RPD uses a robot to build layer on layer. The wire melding is performed in an inert argon gas environment and monitored 2,000 times per second for quality. Machine centers finish the parts and each can produce 22 metric tons of aerospace-grade components. Norsk claims RPD manufactures parts 75 percent less time and cost of forging and expects that the process will be expanded to other aerospace applications.
According to one source, Boeing and Norsk have been working on RPD since 2016 to meet the Federal Aviation Administration’s rigorous certification standard for the components both from a type and production standpoint. A search did not find any published special conditions, but there are several ASTM standards and material specifications for use of titanium in aerospace applications; so, perhaps those references were used.
Norsk and Boeing hope that the Aircraft Certification Office will approve the material properties and the RPD so that other Dreamliner parts may be manufactured this way. With such a range of 3-D printed parts qualifying, in essence for TCs and PCs, the economies of scale will reach good economic returns as well as safety benefits. According to a technical journal, titanium might be used on these components:
Table 1 Examples of application of titanium alloys for airframe
|Material||Example of Application|
|Ti-6AI-4V||Cockpit window frame, Wing box, Fastener|
|Ti-10V-2Fe-3AI||Landing gear, Track beam|
|Ti-6AI-2Sn-4Zr-2Mo||Exhuast, Tail cone|
It appears that these two companies have indeed wrought a significant breakthrough in aerospace design/production. It is also important to acknowledge that the FAA’s certification team and their new performance certification approach, helped capture this innovation.