As metal additive technology continues to gain momentum in the design and industrial production of new aerospace components, GE Aviation’s Loyang plant is the premier maintenance, repair and overhaul (MRO) facility in the world. world to be approved to use metal additive manufacturing (AM) for commercial jet engine component repairs.
GE Aviation Engine Services Singapore (GE AESS) currently employs more than 1,700 people in the city-state and accounts for more than 60% of GE Aviation’s global repair volume. GE Aviation is constantly innovating in the MRO sector, and GE AESS recently announced that it is the world’s first MRO facility approved to perform metal additive repairs on jet engine components.
3D printed parts are usually printed using STL files generated from CAD drawings. However, this only works for new production where the goal is to produce identical parts according to the drawing. When repairing used parts, however, the repair must be customized for each individual part because each part wears differently during service.
Additive technology in repairs also offers the possibility of embracing complexity, rather than running away from it. Chen Keng Nam, executive director of manufacturing at GE AESS in Singapore, was also involved in the deployment of the metal additives.
“This disruptive technology can be used for many applications, not just in aviation. When I look beyond the realm of repair into new, it’s mind-blowing to see the parts we can design and print using additives. Today, designers are using the ability to produce new designs that could not previously be imagined or made with traditional methods.
Iain Rodger, Managing Director of GE AESS, also sees the potential of metal additive technology in MRO.
“In this part of the supply chain, our customers really appreciate the faster turnaround times, and that’s what we’re realizing. By using our GE Additive Concept Laser M2 machines generally cuts the time it takes us to repair these aircraft parts in half.
Rodger says his teams are already using additive technology to repair GE Aviation parts CF6 engines used on widebody aircraft. The next goal is to include parts on the widely used CFM56 commercial aviation engine.
An example is the repair of high pressure compressor (HPC) blades that operate at high speeds and with tight clearances in aircraft engines. They face regular erosion and wear, which over time requires ongoing repair and replacement. Repairing these blade tips previously required a lengthy process of cutting, welding, and grinding to create the proper shape.
GE Aviation has implemented an automated AM process to repair HPC blade tips, saving time and cost associated with labor and machining. The team created image analysis software that maps the shape of a used blade and creates custom instructions for the Concept Laser M2 machine to build a new tip with precise alignment and profile.
The 3D printed part has an almost clean shape and can be finished with minimal additional processing.
“Productivity has increased with our employees able to repair twice as many parts in one day compared to the conventional repair process. Less equipment is also needed for post-processing, so the floor space required is reduced by a third,” says Rodger.
“We are currently evaluating what we are going to do in turbine parts and other components beyond compressors. On a daily basis, working with customers, they will know there is a difference because they will see their parts come back to them faster.
Beyond the much faster turnaround times possible with metal additive technology in aircraft parts repairs, Rodger sees another significant win for GE Aviation, for customers, and for the aviation industry more broadly.
“For me, one of the significant benefits of the additive is its durability. This is going to allow us to repair more parts and throw fewer parts in the trash, use less energy, generate less waste and to have a smaller footprint.Repairability is an important part of the journey to sustainability.As the industry grows and new technologies are developed, this will only increase.
As part of its national high-tech strategy, the Singaporean company Economic Development Council supported initial development trials and training for the introduction of metal additive technology for aviation maintenance in the country.
Shih Tung Ngiam, senior technical manager at GE AESS, has been involved in the project since its inception. It acts as a bridge between the local team and the wider GE Aviation additive community and GE Additive industrialize the process.
“While teams at the GE Aviation Additive Technology Center in Cincinnati and GE Additive Lichtenfels in Germany worked on developing the print settings for the Concept Laser M2 machine, our team here in Singapore focused on the changes needed to making the process robust and production-friendly a high-volume repair process,” says Ngiam.
The Singapore team designed tools to efficiently prepare and print parts and fine-tuned the repair process, including printing, pre- and post-processing, and inspection. Extensive trials and tests have been carried out to ensure the quality and safety of parts before repair is warranted.
In 2020, Ngiam and the team also designed a pilot production line, including an automated powder recycling system, to streamline the repair operation. The COVID-19 pandemic disrupted the approach for some time; however, in 2021, the Loyang team was ready to commission its full-scale production line.
“The additive gives us speed and productivity with less floor space required. We thought long and hard about how best to integrate the M2s into the rest of the repair line. parts of the repair that we should leave out, parts that could benefit from an additive, and other changes we needed to make to the repair process for it to make sense,” says Ngiam.
The two big advantages that the metal additive offers to the site are speed and near net shape product. This allows the team to increase productivity and reduce required floor space. Traditional HPC blade repair methods involve a lot of effort to weld the blade, then a lot of extra effort to remove the excess material. By using Concept Laser M2 metal 3D printers, the repaired blade is very close to the final shape when it comes out of the machine, so much less labor and equipment is required to achieve the finished profile.
Given the critical nature of aerospace components, extensive analysis and testing is required before a repair can be approved, especially when new technologies such as AM are involved. 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. As the aerospace industry becomes more familiar with additives, the approval process can be streamlined.
Back in the field, as GE AESS begins to scale metal additive technology for aircraft parts repair, a real consideration is the talent that will be required to implement the ambitions.
“Singapore’s universities and polytechnics train a good number of PA students, but the pool of experienced graduates is still quite small. As the industry matures and these graduates gain experience, we expect Singapore’s additive talent pool to grow accordingly,” says Chen Keng Nam.
And that fuels a plan for the future, where AM is a mainstay of the aircraft repair supply chain.
“Additive’s big dream is to print spare parts on demand without even having to have an inventory. It is true that it is in a few years, but it will happen. But we also need to recognize that change can take time, especially in our highly regulated industry, and we need to put effort into proving that our new methods are as good as, if not better than, those that came before,” Ngiam concludes.