The 76th Commodity Maintenance Group and Reverse Engineering and Critical Tools (REACT) Laboratory at the U.S. Air Force Base in Tinker, Oklahoma, has announced the ability to cast aluminum parts. The military base is using ExOneS-Print equipment to 3D print sand-casting molds to cast aluminum parts weighing up to 120 pounds in its new foundry. The 76th CMXG can produce products up to Class B standards, and researchers are perfecting its process to soon be able to produce Class A castings, meaning nearly perfect castings.
A sandcastle model sits on a table in front of the ExOne S-Print sand 3D printer at Tinker Air Force Base in Oklahoma.
Examples of sand molds and raw sand in a 3D sand printer
The military base has introduced a new tool to address the difficulty of procuring parts for traditional aircraft. Components that may not have needed to be replaced earlier in the aircraft’s life are now nearing the end of their useful life, and fewer suppliers are bidding on contract requests.
In the new foundry, parts are made by first 3D printing molds using sand mixed with a binder. The mold is similar to the foam florists use, but denser. Aluminum ingots are melted at the foundry, poured into molds, and allowed to cool. The casting can then be milled to form the finished product.
553rd Commodity Maintenance Squadron welder Ted Fetchik pours molten aluminum into a mold.
As part of the foundry’s expansion plans, the capabilities of the 76th Generation CMXG will continue to grow over the next three years as new technology and equipment are added. Some of the parts currently being produced include bearing housings, fuel fittings, and other parts for propulsion, avionics, and control systems.
Future investments include the purchase of a new furnace to preheat the sand molds before pouring, improving process control, and achieving Class A quality castings. The new investment casting cell will automate shell casting, using robotics to create wax patterns to produce ceramic casting molds. The process enables more complex geometries, near-net shape (ie parts that are very close to the finished product), and extremely smooth castings.
The finished bearing seat for the B-1BLancer aircraft’s avionics cooling system, in front of the rough aluminum casting and the mold used to create the casting.
The 76th CMXG’s mission is to be the premier aerospace maintenance organization in the U.S. Air Force. It provides flexible, responsive aerospace component manufacturing and repair services to the warfighter.
