Back in 2017, GE engineers surprised the world when they took what was then the world’s most powerful jet engine and used its technology to turn it into a power plant that could be capable of generating enough electricity for thousands of households. This feat got plenty of attention, but the team was not finished. A new GE team has now turned the machine into yet another example of the power of innovation. By 3D-printing four key metal components, this GE team proved that the technology could compete with conventional manufacturing methods on cost alone.
“This is a game-changer,” says Eric Gatlin, additive manufacturing leader at GE Aviation. “This is the first time we've done a part-for-part replacement, and it was less expensive doing it with additive than casting. To make sure we demonstrated cost competitiveness, we had four outside vendors quote the parts, and we still came in lower with additive manufacturing.”
This project is also an example of the versatility of lean management, the engine driving GE’s transformation. Adapted from Japan in the 20th century, the lean business philosophy revolves around the idea of continuous improvement. Over the last half-century, it has produced remarkable results in American corporations. GE has used it to improve manufacturing and services, reduce inventory, simplify its office operations and now, speed up innovation.
In brief, additive manufacturing can print metal components from computer files, one layer at a time, allowing engineers to dream up designs that were previously too expensive or otherwise impossible to make. This manufacturing technique can also deliver parts that are lighter or, in this case, less costly to produce. The GE9X, the world’s most powerful jet engine GE developed for Boeing’s new 777X jet, has 3D-printed parts that help improve its fuel efficiency. The team working on Catalyst, GE’s new turboprop engine, took the technology to another level by using it to combine an astonishing 855 parts into just 10 or so.
GE Aviation has been spearheading the push for manufacturing additively. The aviation business division of GE opened its Advanced Technology Center near GE Aviation’s headquarters in Cincinnati, Ohio, and also constructed a commercial 3D-printing plant in Auburn, Alabama.
It was at the Alabama facility where the latest breakthrough took place. As the COVID-19 pandemic scrambled production schedules, the Auburn team found itself with an unexpected capacity to pick up new projects. This all happened just as Gatlin and his team finished their annual review of components that could be 3D-printed. “We are always looking to pull costs out of existing products, so, we cast a wide net that includes hundreds of castings we buy,” he says. “Then we ask, ‘Are we getting more competitive?’ ‘Are there things we couldn’t do a year ago that are now technically feasible?’”
A series of lean workouts, known as kaizens, led the team to four parts in the LM9000 gas turbine engine, a power generator derivative of the GE90, one of the most powerful jet engines in the world.
The GE team considered many different aspects in its workouts: the parts themselves — both new and older — their size, shape, features and materials, as well the capabilities of GE Aviation’s 3D printers. “Our goal was always to look at ways to disrupt production,” says Joseph Moore, a senior project manager and project lead from GE Aviation. “There are only a few suppliers that make investment castings for the aviation industry, so we need to have options to ensure we’re not impacted by obsolescence and reliant on the cost models of specific suppliers. If we can make an additive part for less, we can save money now and avoid any increase in the future.”
By February 2020, the team, which included engineers from GE Aviation and GE Additive identified 180 cast parts for which it thought 3D printing could potentially save money. It split these parts into small groups to calculate the cost of printing each part in comparison to the cost of conventional production.
Just a month later, the team had identified four parts that met all requirements and reached out to colleagues in Auburn to see if the math checked out. “We’re a production shop and would not see a project like this until after GE Aviation’s Additive Technology Center had developed the process for low-rate production,” said Jeff Eschenbach, a senior project manager and project lead at the Auburn facility. “What was different about this project is that we took this on from the very beginning. It created an opportunity for the engineers here on-site to get involved.”
Eschenbach and his group lined up GE Additive Concept Laser M2 Series 5 printers and started making the parts. The M2 is one of GE’s advanced 3D printers with a pair of lasers that melt and fuse metal layers faster than a single laser and can handle complex builds. At either 400 watts or 1 kilowatt, the M2’s lasers are just as powerful as they are fast. The M2’s lasers can produce 50-micron-thick layers at a single pass from a chrome and cobalt superalloy powder. Last but not least, the machine also features a large, 21,000-cubic-centimeter build chamber, which is key for making parts measuring 3.5 inches in diameter and 6 inches tall.
Taking full advantage of the M2’s features, the team realized it could print four parts at once, boost productivity and lower cost — the perfect trifecta in manufacturing. “We said right upfront we were going to pick a material we had already qualified,” Gatlin says. “In production, we opted for the M2 because we know it well. And we were not going to do any wholesale design changes, just some tweaks so we could print the parts successfully. We simplified as many steps as we could so the team could run fast.”
The approach worked. These four 3D-printed parts will reduce costs by as much as 35% compared to traditional castings. Even more impressive is that this process from start to finish took only 10 months. Ordinarily, producing gas turbine parts using a casting process takes 12 to 18 months or more. “The parts were one-to-one replacements, without any redesign or parts consolidation to improve their economics," Gatlin says. "And it was done fast.”
Finally, the project opened new horizons. Says Kelly Brown, senior technical leader at GE Additive: “From a business perspective, Auburn showed muscle we didn’t have in the past, and now we have a bank of parts that we can go after next.”