The Berlin Mitte plant, operated by the power company Vattenfall, is using 3D-printed first-stage heat shields and first-stage vanes inside a single GE natural gas turbine. Each part weighs about 4.5 kilograms (9 pounds) and is the size of a laptop. Muller says they help the turbine run more efficiently and burn less gas. “These are the largest 3D-printed components globally in any commercially operated gas turbine,” says Muller. “3D printing is often thought of in terms of very small, complex components. We’re proving now that actually, you can commercially manufacture large pieces for turbines.”
When operators fire up the machine, these components, which are typically made by casting, glow red-hot at 1,000 degrees Celsius (1,800 Fahrenheit) and must be cooled off by air. The parts can handle the heat since the machine blows a relatively cooler air — about 400 to 500 degrees Celsius — through channels cut into the components to lower their temperature. But this cooling also reduces the turbine’s efficiency.
Enter 3D printing, which involves building a solid object from a digital model by laying down thousands of layers of material one on top of another. This method allows GE engineers to create much more complex pathways than traditional metal casting. The structures include intricate air passages that cool the components more efficiently.
Muller says that when all 50 or so heat shields on the turbine are 3D-printed instead of cast, they reduce cooling flow by more than 40 percent. “That’s millions of dollars in fuel-cost savings per year,” he says. One turbine typically consumes 10 kilograms of fuel every second. After 100 seconds you’ve gone through a ton of fuel, Muller says.
But the real cooling-air guzzler isn’t even the heat shield. That distinction goes to the turbine’s first-stage vane, which is one of the hottest components in an operating turbine. 3D-printed portions of the vane have led to a 15 percent reduction in the need for cooling air. That’s equivalent to approximately $3 million in fuel savings per year.
Muller says that 3D printing has created a “new tribe” of industrial designers who use open-source programs and algorithms. The difference between them and their colleagues who use traditional casting methods is vast, says Muller. “We need to merge the two worlds.”
Gradually, 3D printing is becoming a bigger part of industrial manufacturing, having started in aviation, where there was a great need for complicated, lighter components. Earlier this year GE also opened the $40 million, 125,000-square-foot Center for Additive Technology Advancement near Pittsburgh, where engineers experiment with new ways to print industrial components using high-powered lasers. In late summer the Advanced Manufacturing Works, located in Birr, Switzerland, commissioned the first commercially available 3D printer to operate with four lasers.
In September the company announced it was buying 3D-printer company Arcam AB of Sweden to help it build a $1 billion 3D-printing business by 2020.