External printing providers enable aerospace innovation

Recently, Albert Wimmer, the managing director of Isar Gears, was given a challenge.

“Our aviation customer came up with a new, relatively high-speed electric motor,” he recalls. “They appointed us to design the speed-reduction transmission to drive a propeller, but the difficulty was pivoting the entire unit through providing lubrication in every position.”

Using 3D CAD software Creo, the Isar team designed a fine-veined channel system with outlet nozzles for the oil that was pumped around the system. Then they faced the challenge of building a robust prototype. 

Isar looked to partner with an additive manufacturing expert to build the prototype. It’s a step that a number of companies are taking, owing to the high cost and expertise required to set up in-house additive manufacturing.  

Isar worked with Protolabs, which used metal sintering to create the first prototype, but there was a problem. The additive manufacturing process left metal powder residues that could not be removed and that stopped oil from moving through the narrow channels. 

Protolabs worked with Isar to tweak the design and make it more suitable for additive manufacturing, creating wider exits to the channels to enable them to be emptied. “Protolabs also provided first-class advice for production-oriented designs with special support geometries. We now have a functioning unit consisting of a motor, drive, integrated pump and output flange,” says Wimmer.

The companies also worked together on an internal helical ring gear character with a “very sophisticated geometry, meaning extremely long tooling times in standard production processes,” says Wimmer. Instead, Isar uploaded its design to Protolabs where it was checked for feasibility and optimised before production using additive manufacturing.