Machining Cold Spray Additive Manufacture for the UH-60 Main Transmission Sump

A new additive manufacturing (AM) process, high pressure cold spray, has shown to provide structural integrity along with improved machining characteristics compared to existing thermal spray processes. The U.S. Army overhauls the UH-60 Black Hawk helicopter components including the transmission and gearboxes. When performing the overhaul of the transmission assembly, corrosion has been found on the transmission housings. The cold spray AM process was used to repair corrosion to an existing sump housing. Using inspection, stress analysis, and testing, the cold spray AM was qualified from an airworthiness perspective as a replacement to thermal (flame) spray processes. Re-establishing blueprint tolerances on an existing operational sump housing required employing techniques not used at initial manufacture and gave improvements on the setup and final surface finish. The cold spray repair was found to be cost effective. This repair can be employed on other similar magnesium alloy housings and aluminum alloy housings.