Safran Power Units Sees 3D Printing as Differentiator

 - September 14, 2017, 12:45 PM

Safran Power Units (SPU), eyeing a larger presence in the business-jet market, plans to capitalize on its growing additive manufacturing capabilities to drive down auxiliary power unit (APU) production costs and develop more advanced, efficient motors.

The company recently revealed the most relevant achievement to date in this strategy, announcing European Aviation Safety Agency (EASA) certification of an additive-manufactured, or 3D-printed, turbine blade nozzle for the eAPU60 on the Leonardo AW189. The certification—EASA's first for a 3D-printed hot-section APU part, according to SPU—is a clear sign that Safran’s multi-year effort to develop less expensive parts is gaining traction in design, industrialization and certification.

The company's complete mastery of the additive manufacturing process" allows it " to offer our customers lighter engine components and reduced manufacturing cycles, whether for new or spare parts," said CEO Fran├žois Tarel.

The next step is mass production of the eAPU60 nozzles. SPU plans to expand the process to other parts. The big-picture goal is to develop the capability to 3D print 30 percent of the parts in a notional clean-sheet APU design within five years. 

"We will do it step by step, going deeper into the core of the engine," Tarel told AIN. "And we can take validated parts and expand them to other programs."

Safran has contracts to supply the APUs for the Bombardier Global 7000 and the Dassault Falcon 5X—SPU's first civil fixed-wing applications. A long-time military supplier and the former Microturbo, SPU teamed with Pratt & Whitney on the business-jet APUs before taking them over in 2014. Both APUs are made in a 22,000-sq-ft facility in San Diego, Calif. opened in September 2015 as part of an effort to expand the company’s civil business. The production area occupies 6,500 sq ft. 

The San Diego location is seen as the driver of winning more civil business in North America, Tarel said. It is the company's second U.S. location, joining Safran Power Units Dallas, which focuses on supplying military power units and will provide APU services. SPU has three dedicated facilities—the Toulouse, France, headquarters, and the two U.S. locations. It also offers product support from Safran facilities in Australia and the UK, which Tarel said is key to expanding into the civil market.

SPU generates 75 percent of its business from APU work, with the rest coming from military missile turbojet engines. The business is also Safran's center for work on fuel cells, which Tarel believes has significant potential.

"We want to provide solutions to the aircraft manufacturer where we can bring power on board with the current type of design, the gas turbine, but also maybe hybrid technology and, in the long term, fuel cells," he said.

A New Approach

For now, the largest opportunity is expanding the additive manufacturing capabilities. The eAPU60 nozzle is manufactured by selective laser melting (SLM) using hastelloy X, a nickel-based material. The 3D-printed nozzle is 35 percent lighter and consists of four parts versus eight using the traditional manufacturing technique.

SPU works closely with two Australian partners, Monash University and its spin-off company, Amaero Engineering, on 3D manufacturing. Amaero provided two SLM machines for SPU's Toulouse facility, while Monash and Amaero teams customized the machines for producing parts to SPU's specifications. SPU handles the post-processing, final machining and assembly.

The process has required a shift in thinking within SPU, Tarel explained. Traditional manufacturing operations don't always locate designers and production in the same place. For additive manufacturing to work well, he said, design engineers must be close to the production process so they can easily test and refine their designs. To support this, SPU has installed small 3D printers in the design center to help engineers with prototyping.

"You need to design [3D-printed] parts differently," Tarel said. "In this kind of process, you can do it all at once. You can do in a single part what you used to do in several parts, and to do that, the design engineers must think differently."

Getting the first part certified showed not only that SPU can make the parts, but also that it understands how to navigate the certification process. The company relied on "intensive" endurance tests and, with help from parent Safran, "extensive" materials testing to gain EASA approval.

"If tomorrow I was to design a turbine nozzle with additive manufacturing, I can take this experience and say I know how to demonstrate it, and I know what fits with EASA rules for approval," Tarel said. "We are getting experience not only in the process itself, but also the ability to industrialize and certify. For us, it’s an important step."