courtesy of MTU Aero Engines
One of seven EOS AM systems in use at MTU’s Munich facility
In the aerospace game fuel consumption (or a lack of) is king. As the availability of fossil fuels dwindles fuel prices rise, this, in turn, hits the pockets of passengers and freight companies thus making air travel less appealing. As a technology that offers free complexity and allows for topological weight saving solutions it is easy to see why the aerospace industry is turning to 3D printing in its quest to burn less fuel.
The latest development comes out of Munich, Germany as MTU Aero Engines announces that it is using EOS technology for series production of components in order to help Airbus achieve its 15 per cent reduction in fuel consumption for the A320neo.
MTU Aero Engines, Munich, which develops, produces and supplies components for civil and military aircraft engines (as well as for power generation gas turbines), is a primary supplier to US manufacturer, Pratt & Whitney, whose PW1100G-JM geared turbofan (GTF) engine is one option for powering the new Airbus A320neo jetliner.
The Munich company, which currently operates seven additive manufacturing (AM) machines from EOS, has started using them for series production of nickel alloy borescope bosses. They form part of the turbine housing for the A320neo’s GTF engine and allow the blading to be inspected at intervals for wear and damage using an endoscope, which in the aerospace sector is termed a borescope.
courtesy of MTU Aero Engines
Nickel alloy borescope
An additively manufactured nickel alloy borescope boss from MTU Aero Engines for the high-speed, low-pressure turbine of the Pratt & Whitney PW1100G-JM geared turbofan engine, which will power the A320neo
Previously, the bosses were cast, or milled from solid. It was the cost advantages of using EOS technology that was the decisive factor in adopting AM for this application, both in the development stages and in production. The Pratt & Whitney PW1100G-JM is the first aero engine to be equipped with borescope bosses produced by additive manufacturing.
The components are built layer by layer from nickel alloy powder that is melted by laser and allowed to harden so that each layer fuses to the one below. The method was originally used for rapid manufacturing of prototypes but is increasingly used for manufacturing components in significant quantities.
Advantages of the process include more design freedom as well as the possibility of using a wide range of raw materials, from light, flame retardant plastics to a variety of metals. Production requires less material and the tool-free manufacturing process considerably reduces lead-times.
Preparations for series production of the borescope bosses at MTU have now begun. Sixteen parts per build are envisaged, totalling up to 2,000 parts per year. The percentage cost saving compared to previously established manufacturing processes is expected to be in double figures and the quality level is already high. MTU and EOS are working together to optimise the finish of the component surface.
As MTU is a producer of raw materials, the company was able to develop a new process chain, which has been integrated into the manufacturing system. It is underpinned by a control system specifically developed by MTU. Online monitoring captures each individual production step and layer. In addition, new quality assurance procedures were introduced, such as optical tomography. The German Federal Aviation Authority has certified the EOS manufacturing platform.
Dr Karl-Heinz Dusel, Director of Rapid Technologies at MTU said, “About ten years ago, we began using AM to produce tools and development components. To optimise utilisation of the capacity, we went in search of further areas where we could apply the technology.
"The borescope bosses for the low-pressure turbines of the A320neo’s GTF engine were ideal for AM. They are small components riveted to the turbine housing that create openings to allow technicians to check the condition of turbine blades inside the engine.
“We see a lot of potential for the manufacture of further series components for aero engine construction, such as bearing housings and turbine airfoils, both of which need to meet the highest demands in terms of safety and reliability.”