The use of three-dimensional (3-D) printing is not new to the U.S. Air Force (Washington, DC, USA), which has routinely used the process for legacy aircraft requiring parts that may be out of production due to manufacturing obsolescence.
However, 3-D printing is now becoming more commonplace in the Air Force’s supply chain for its fifth-generation aircraft. In December 2018, a metallic 3-D printed part was installed by the 574th Aircraft Maintenance Squadron (AMXS) maintainers for the first time on an operational F-22 Raptor during depot maintenance at Hill Air Force Base in Utah.
“One of the most difficult things to overcome in the F-22 community, because of the small fleet size, is the availability of additional parts to support the aircraft,” says Robert Lewin, 574th AMXS director.
The use of 3-D printing gives maintainers the ability to acquire replacement parts on short notice without minimum order quantities. This not only saves money, but also maintenance time.
The printed bracket will not corrode and is made using a powder-bed fusion process that utilizes a laser to build the part layer by layer from a titanium powder, the Air Force explains. A new bracket can be ordered and delivered to the depot for installation as quickly as three days. The printed part replaces a corrosion-prone aluminum component in the kick-panel assembly of the cockpit that is replaced 80% of the time during maintenance.
“We had to go to engineering, get the prints modified, we had to go through stress testing to make sure the part could withstand the loads it would be experiencing—which isn’t that much, that is why we chose a secondary part,” says Robert Blind, modifications manager at Lockheed Martin (Bethesda, Maryland, USA).
The part will be monitored while in service and inspected when the aircraft returns to Hill AFB for maintenance. If validated, the part will be installed on all F-22 aircraft during maintenance.
The printed titanium bracket is only the first of many metallic additive manufactured parts planned through public-private partnerships, according to the Air Force, which adds that there are at least five more metallic 3-D printed parts planned for validation on the F-22.
“Once we get to the more complicated parts, the result could be a 60-70 day reduction in flow time for aircraft to be here for maintenance,” Lewin says.
Source: Defense Visual Information Distribution Service, www.dvidshub.net.