GE Aviation Singapore is First MRO Facility to Repair Jet Engines with Metal 3D Printing

GE Aviation’s Engine Services Singapore (GE AESS) is the first maintenance, repair, and overhaul (MRO) facility approved to use metal additive manufacturing for commercial jet engine component repairs. The site is already using GE Additive’s Concept Laser M2 3D printers to repair parts in CF6 turbofan engines produced by GE Aviation.

With over 1,700 employees, GE AESS accounts for more than 60% of GE Aviation’s global repair volume. Moreover, as the subsidiary starts to scale metal additive technology for aircraft part repairs, it will need more talent to execute its ambitious plan. Significantly since its expanding the use of the technology to repair parts on the CFM56, one of the world’s best-selling aircraft engines produced through a 50/50 Joint Venture between GE and Safran Aircraft Engines.

“In this part of the supply chain our customers truly value faster turn-around time, and that’s what we are achieving. Using our GE Additive Concept Laser M2 machines typically halves the amount of time it takes us to repair these aircraft parts,” pointed out Iain Rodger, GE AESS’ Managing Director.

As one of the key hubs for GE in the Asia-Pacific region, GE AESS provides aircraft engine component manufacturing and repair services for more than 100 customers, including BoC Aviation, the SIA group of companies, and ST Aerospace. Additive manufacturing is taking force at two of GE AESS’ Engine Component Repair facilities in Loyang, where it leverages global know-how and shared expertise with the supply chain network.

But repairing used parts means the teams have to customize individual components because they wear different during service. Moreover, given the critical nature of aerospace parts, extensive analysis and testing are required before any repair can be approved, even more so when new technologies such as 3D printing are involved.

From Left to Right; Lisa Tan, lead scientist at GE Aviation Engine Services Singapore, Singapore Minister for Trade and Industry, Gan Kim Yong and Singapore Economic Development Board (EDB), Executive Vice President, Tan Kong Hwee. Image courtesy of GE Aviation.

GE AESS worked closely with GE Aviation Engineering to produce parts for testing and to establish a robust quality-assurance process before the process could be approved. The initial development trials and training for introducing metal additive technology for aviation maintenance in the country were supported by Singapore’s Economic Development Board as part of its national high-tech strategy.

While teams at the GE Aviation Additive Technology Center in Cincinnati and GE Additive Lichtenfels in Germany worked on developing printing parameters for the Concept Laser M2 machine, the Singapore group focused on the modifications needed to make the process robust and production-friendly in a high-volume repair process.

Then, Senior Engineering Manager at GE Aviation, Engine Services in Singapore, Shih Tung Ngiam, and his team designed the tooling to prepare and print parts efficiently and fine-tuned the repair process, including printing, pre- and post-processing, and inspection. Later, extensive trials and tests were conducted to ensure the quality and safety of the parts before the repair was substantiated.

Finally, in 2020 they also designed a pilot production line to streamline the repair operation, including an automated powder recycling system. But with Covid-19 lurking in the background, plans were halted until 2021, when the team in Loyang was ready to go live on its full-scale production line.

“Additive gives us speed and productivity with less floor space required. We gave a lot of careful consideration to how best to integrate the M2s into the rest of the repair line. We completed an assessment of which parts of the repair we should leave alone, which ones could benefit from additive and what other changes we needed to make to the repair process for it to make sense,” revealed Ngiam.

One of the earliest examples is the repair of high-pressure compressor (HPC) blades, which run at high speeds and tight clearances within aircraft engines. As a result, they face steady erosion and wear and tear that, over time, demand continuous repair and replacement. However, repairing these blade tips required a long process of cutting, welding, and grinding to create the proper shape.

To tackle this problem, GE Aviation has established an automated additive manufacturing process to repair the HPC  blade tips, saving time and costs associated with labor and machining. The team created image analysis software that maps the shape of a used blade and creates customized instructions for the Concept Laser M2 machine to build a new tip with precise alignment and profile. The 3D printed part is the near net shape and can be finished with minimal additional processing.

While traditional methods for repairing HPC blades involve a lot of effort to weld the blade and then additional steps to remove the excess material, the Concept Laser M2 metal 3D  printers come very close to the final shape of the repaired blade once it is out of the machine, resulting in much less labor and equipment to achieve a finished profile.

GE Additive’s Concept Laser M2 Series 5, perfectly suited highly-regulated demands of aerospace industry. Image courtesy of GE Additive.

“Productivity has increased with our employees able to repair twice as many parts in a day  compared to the conventional repair process,” highlighted Rodger. “Less equipment is also needed for post-processing so the floor space required is reduced by one-third. Further to that we are currently assessing what we are going to do in turbine parts and other components beyond compressors. Day-to-day, working with customers, they will know that  there’s a difference as they will be seeing their parts return to them more quickly.”

According to the multinational firm, the three big advantages of metal additive are speed, a near-net-shape product, and sustainability. Not only can teams increase productivity and reduce floor space required, but it will reduce waste, use less energy and produce a smaller footprint.

Additive technology in repairs also allows embracing complexity rather than shying away from it. GE AESS Executive Manufacturing Leader Chen Keng Nam has been involved in the metal additive roll-out and said that the technology’s characteristic disruptivity could work with many applications, not just aviation.

“When I see beyond the realm of repair into new-make, it’s mind-blowing to see the parts we can design and print using additive. Now designers are using the ability to produce new designs that couldn’t be imagined or manufactured before with traditional methods,” suggests Keng Nam.

Hoping additive manufacturing will remain part of the aircraft repair supply chain in Singapore and expand to other brand facilities globally, GE AESS wants to prove that the new methods are suitable, if not better than what has already been explored. But even though the company dreams of printing spare parts on-demand without even needing to have an inventory, “change can take time,” it acknowledges, and in the highly regulated aviation industry, they must “make efforts to prove their new manufacturing possibilities.

Feature image courtesy of GE.