GE Casts Welding Aside for Jet Engines
Historically, the manufacture of jet engines has revolved around the centuries-old processes of casting and welding. But GE may trigger a change in the industry by departing from this process and opting instead to use lasers and metal allow powder to create these ultra-precise components.
The process, called selective laser sintering (SLS) could soon become a part GE's production process for everything from gas turbines ultrasound machines. Currently it is used for specialty products, like customized medical implants and plastic prototypes. But the decision to implement SLS for high-stress environments like the inside of a jet engine is an entirely different matter.
What's unique about a jet engine is that despite the extreme operating conditions, we count on it for our lives. While additive manufacturing can yield incredibly precise yield, the fact is that sintered metal is not guaranteed to have the same physical properties as cast metal.
This is because the process uses a pinpoint-accurate laser that selectively shoots and melts cobalt-chromium powder in layers. After each 20-micrometer-thick layer has been melted on top of the one below, resulting in the exact item you want with no scrap materials left over.
What this brings to the table are lightweight components and significant materials cost savings, with minimal operator oversight. And with lighter components come lighter, more fuel-efficient aircraft. Not only that, but if engineers want to tweak the part's design, it doesn't come with the added cost of reconfiguring an entire assembly line.
To take advantage of additive manufacturing's perks without risking critical part failure, GE purchased two companies last fall that specialize in automated precision manufacturing and integrated them into GE Aviation.
The technology will be used for a fuel nozzle for CFM International's LEAP jet engine, and is slated for integration into planes in late 2015 or early 2016. Each engine will use between 10 and 20 nozzles, putting GE's three-year quota at 25,000 SLS-made parts.
Perhaps these nozzles don't seem as critical as turbine blades, but this will nonetheless be the first major test as to whether additive manufacturing will find a home in aerospace.
Full story at MIT Technology Review