15 % less fuel consumption – this is the primary benefit that the manufacturer Airbus wants to give customers with its A320neo, a new short- and medium-haul aircraft. Achieving the goal requires, above all, more efficient engines. MTU Aero Engines is a primary supplier to the US engine manufacturer Pratt & Whitney and plays a key role in Airbus reaching its objectives. In order to remain at the forefront of technology, the Munich-based experts in aircraft engines actively supports the use of innovative production processes. Additive Manufacturing plays an important role here, as shown in the manufacture of borescope bosses - access points for inspecting turbines - a product for which MTU relies on EOS technology.
The Additive Manufacturing of borescope bosses for series production has been a great success. Once again this proves MTU‘s commitment to innovation leadership. We produce one of the world‘s most advanced engines – the Geared Turbo Fan – with some of the world‘s most advanced processes.
Borescope bosses will be used on the latest generation of engines – the Geared Turbo Fan (GTF) – and they will be manufactured using EOS machines. “At the beginning of the second phase we started to produce raw components, which replaced existing parts. The bore-scope bosses for the low-pressure turbines of the A320neo-GTFs fell into this category,“ explains Karl-Heinz Dusel. These small add-on components allow technicians to check the condition of turbine blades inside the engine using endoscopes. The parts are riveted to the turbine housing to create an opening for the endoscope, which in the aerospace sector is termed a borescope. Heat resistance and durability are the key characteristics of the nickelbased alloy that was used. This highquality material achieves the best results demanded by the component, but it is difficult to machine. Fortunately, a problem like this is easily overcome with Additive Manufacturing. As MTU is also a producer of raw materials, the company was able to develop a new process chain, which has been approved and integrated into the manufacturing system. The entire manufacturing process 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 even certified the EOS machines. In the past, the borescope bosses were cast, or milled from a solid, but the low-pressure turbines for the A320neo’s Geared Turbo Fan are the first turbines to be serially equipped with borescope bosses produced using Additive Manufacturing. Above all, it was the cost advantages of the EOS technology that were the decisive factor, both in the production itself and in the development stages.