Travis Air Force Base, Calif. -- The 60th Maintenance Squadron successfully created a C-5 mixing chamber repair from a component manufactured on the Stratasys Fortus F900 3D printer, a first for Travis AFB.
Around 4 a.m. on Oct. 12, the Metals Technology shop received a C-5 fuel mixing chamber that sustained damage to the flange at the alternate air valve. The damage exceeded the traditional local repair capabilities and no replacement part was immediately available.
“Our departments worked together, Metals Tech came up with the great idea in the first place,” said Jeffrey Bruns, 60th MXS aircraft metals technology section chief, as he explained further the ingenuity behind the repair.
Kyle Parr, 60th Maintenance Squadron aircraft structural maintenance supervisor, introduced the idea that a bond form could be manufactured on the industrial strength polymer 3D printer. He proposed the unique polymer material has the airworthiness characteristics necessary to be used on aircraft.
After collaboration with Aircraft Metals Technology, Aircraft Structural Maintenance and the on-site C-5 liaison engineer, the decision was made to leave the hat sleeve in place, using it not only as a bond form for new fiberglass material, but as stiffening support for increased part longevity.
By 9 a.m., the engineering repair request was submitted locally and approved later that same day by the oversight C-5 engineering team at Robins AFB, Georgia.
The Metals Tech team manufactured the 3D printed hat sleeve and Sheet Metal team worked to attach it to the mixing chamber and bonded new fiberglass around the polymer flange. The repair was accomplished quickly and cost approximately $245, which is roughly the same cost for comparable aluminum material of that size.
“Not many, if any, 3D printed repairs exist, so we constantly work to integrate our 3D printer as a tool to help repair our aircraft,” said Tech. Sgt March Tighe, 60th Maintenance Squadron aircraft metals technology noncommissioned officer in charge. “This is a part of a larger Advanced Manufacturing Technology push, not only across our career field but our nation, so proving its viability makes us all proud.”
A metal sleeve would have taken significantly more time. With the advanced capabilities of 3D printing, the part was restored exactly to its original specifications, without adding a large amount of significant additional weight to the component.
Metals Tech also supplied a 3D test piece of the same material to assess whether or not the product would adhere to the surface of the 3D material.
“We were surprised at how well it did adhere to the material. In my opinion, the repair would be much stronger, stiffer, and more perfectly round than the original flange. It created a better, longer lasting seal, that will hopefully extend the life of the flange and system,” said Bruns.
Tighe noted it was impressive to see a new technology be integrated seamlessly by many different agencies to accomplish a repair that has never been completed in less than 39 hours.
“The cool thing about this repair is that it is the first time we were able to get our C-5 engineers to sign off on us utilizing 3D printing as part of a larger repair; typically, we only manufacture interior trim panels,” said Tighe. This repair is crucial for these mixing chambers because they're a vital aircraft component that you can't buy or make anymore…to be able to come up with an interim repair is a big win for the C-5 and us locally.”
At 7 p.m. on Oct. 13 the new part was completed and released for installation back on the aircraft