More than one-third of the advanced turboprop engine under development by GE Aviation will be manufactured using 3D printers, the company says.
GE started using additive manufacturing techniques to build engine parts in 2010, beginning with the cobalt chromium fuel nozzles inside the CFM Leap-1 engine, which GE produces with joint venture partner Safran.
But the company decided to double down on additive manufacturing for the ATP that is selected to power the Cessna Denali single-engined turboprop.
As the ATP entered the design phase, GE engineers were testing an “additive demonstrator” of the CT7, the turboshaft engine from which the ATP is derived. The results achieved by the small team of eight engineers stunned chief engineer Mohammed Ehteshami. More than 900 non-rotating engine parts were reduced to just 16, resulting in a 35% weight reduction for the overall engine.
The results were so impressive that GE decided to halt the six-month-old design process, allowing engineers to insert a variety of 3D printed metallic parts.
When the ATP design re-appeared, 35% of the metal parts were intended to be 3D printed. Ehteshami says 855 parts were replaced with 12 made additively, including frames, combustor liners, sumps, exhaust case, bearing housings, stationary components in the flowpath, and heat exchangers.
The changes reduced the overall weight by 5% and improved specific fuel consumption by 1% compared with the original design, he adds.
Designers stopped short of using 3D printers for rotating components such as blades, discs and rotors.
GE has decided to assemble and test the ATP in Prague, Czech Republic, the site of a new centre of excellence for turboprop engines established by the company a year ago. It is still reviewing locations for building the 3D parts used in the ATP.