Faster and Cheaper: Replacing Cast Parts of Gas Turbine with 3D Printed Ones
This is a guest contribution by Egor Driagin, CMO at Top3DGroup
General Electric often tries to cut the costs of production. For example, saving 35% during the production of gas turbines by replacing traditional casting with additive technologies.
Such tests will show whether this can help to save money. They are conducted by two divisions of General Electric: GE Additive and GE Aviation. In February 2020, GE Aviation audited and chose 180 types of cast parts that can theoretically be replaced with 3D-printed ones. The program was launched with the idea to find out if it’s cost-effective in practice.
According to Joseph Moore, a project lead from GE Aviation, the majority of aviation companies provide replacement parts for the lifetime of the products. But if there are only a few spare parts left, and there are plans to discontinue the material from which the parts are made, one would wonder what will happen.
“We need to figure out how to come up with replacements before we run out of parts,” Moore said. “We need to move quickly through the development cycle and create a part we can actually ship. To prove we could do it, we were put under a deadline and told to do the part as quickly and cost-efficiently as possible.”
The list of potential experimental parts was slowly cut to just a few ones with certain sizes and material: either titanium or heat-resistant cobalt-chrome alloy. The final list consisted of four parts that were the components of the adapted for air filter system of the gas turbine LM9000
New turbines are made for an oil-gas company Baker Hughes, the company with the majority of shares are owned by GE. The power train in question is GE90 — the most powerful one in the world. It lifts Boeing-777 off the ground. The turbines were designed after a 2018 order of around 20 turbines. It was put by a Russian gas company Novatek that is working on the “Arctic LNG 2” project: producing liquefied natural gas at the Utrenneye field in Yamal-Nenets Autonomous Okrug, Russia.
3D printed cobalt-chromium components (can be seen in the first and the last pictures) with a diameter of 90 mm and height of 150 mm are made on the 5th gen. Concept Laser M2 3D printer using Selective Laser Melting (SLM) technology. These industrial systems with the available volume of 21 l are equipped with 400 or 1000 W laser beams. They can produce the prints using various metal powders, working on the minimum layer thickness of 50 microns.
Concept Laser is also working under GE: American Corporation acquired 75% of Concept Laser in Fall 2016, the deal cost $599 million, while GE also bought an electron beam 3D printer manufacturer Arcam for $700 million. Now the industrial 3D printers under the brand names Concept Laser and Arcam are actively used in additive manufacturing of gas turbines and aircraft engines by GE, including GE9X turbofan engines GE9X that replaced the original GE90 ones on the Boeing 777-8 and Boeing 777-9 aircraft. The list of serially produced 3D printed components of these engines includes thermal sensors, swirlers, heat exchangers, and low-pressure turbine blades made from titanium aluminide.
The main thing about the experiment is that the engineers at GE for the first time ever used 3D technologies to recreate the existing parts instead of designing new ones. The process took 9 months instead of 12-18, with the full production cycle: from choosing the parts to manufacturing. The costs were cut in half.
“This is a game-changer,” GE Aviation Additive Manufacturing Leader Eric Gatlin said. “This is the first time we did a part-for-part replacement, and it was cheaper 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.”
“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.”, says Joseph Moore.