We've only just begun to see the huge impact 3D-printing technology will have on manufacturing, and the aerospace industry is a prime example. Earlier this year we saw the first example of a 3D-printed jet engine, now GE has announced the first 3D-printed part certified by the US Federal Aviation Administration (FAA) for a commercial jet engine. The fist-sized T25 housing for a compressor inlet temperature sensor was fabricated by GE Aviation and will be retrofitted to over 400 GE90-94B jet engines on Boeing 777 aircraft.

The T25 housing is located inlet to the high-pressure compressor and protects the sensor electronics from cold and being buffeted by airflow, and is the product of a decade's experimentation in additive manufacturing. In this, the usual fabrication methods of casting or milling metal are replaced by building up a part layer by layer guided directly from a CAD file like a hobbyist's 3D printer.

The difference is that instead of making an item by adding layers of molten plastic, the T25 housing is made of a fine powder of cobalt-chrome alloy. This is spread out in a flat layer and a laser or electron beam fuses a section of the CAD plan in it. Another layer of dust is laid down and the process is repeated. When the printing is completed, the excess powder is blown and brushed away, and the part is given a finish.

This method has a number of advantages. The part can be made lighter and extremely complex shapes can be made in a single piece, instead of several fitted together. This allows for designs that were previously impossible, much faster turnaround times from design to finished product, and much lower manufacturing costs with very little waste.

According to GE, making a prototype of the T25 would have taken a year longer using conventional methods.

Though the T25 is the first 3D-printed part to go into service, it won't be the last. GE says that the next-generation LEAP jet engine currently being flight tested will include 19 3D-printed fuel nozzles. In addition, 3D-printed fuel nozzles and other parts are also under development for the GE9X engine for Boeing’s new 777X aircraft; the largest jet engine ever built. The new engines' development also includes ceramic matrix composites (CMCs) and carbon-fiber fan blades.

"The 3D printer allowed us to rapidly prototype the part, find the best design and move it quickly to production," says Bill Millhaem, general manager for the GE90 and GE9X engine programs at GE Aviation. "We got the final design last October, started production, got it FAA certified in February, and will enter service next week. We could never do this using the traditional casting process, which is how the housing is typically made."

Source: GE

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