Additive manufacturing allows design of environment-friendly aircraft engines
The Fraunhofer Institute for Production Technology IPT and the Chair for Digital Additive Production DAP at the RWTH Aachen are currently developing a process chain for the production of Blade Integrated Discs (BLISK) in which the additive manufacturing process “Laser Powder Bed Fusion” (LPBF) is integrated. The turbomachinery experts at the Fraunhofer IPT have been working for years on sustainable concepts, methods and tools for aviation. Together with the Chair of Digital Additive Production DAP at RWTH Aachen University, they have now taken a closer look at the process chain for manufacturing engine components, in particular Blade Integrated Discs (BLISK). State-of-the-art BLISKs are manufactured from nickel-based superalloys, among other materials. This material is difficult to machine, so that the production of the blade profile by established milling is very time-consuming and cost-intensive. For this reason, the researchers questioned the conventional manufacturing processes and instead tested the additive technology “Laser Powder Bed Fusion” (LPBF). Metal powder is melted layer by layer by a laser beam according to the geometric information.
Using a BLISK as an example, the researchers are demonstrating a holistic process chain for the manufacture of engine components – from design and layout to additive manufacturing, heat treatment, subtractive finishing and quality assurance. The aim is to produce the BLISKs, especially the blade profiles, close to their final contours so that only a small amount of excess material has to be removed. For this reason, the researchers first had to develop a suitable LPBF production process for BLISKs. Grid structures support the thin-walled component during assembly and minimize vibrations during post-processing.
The use of additive technologies has many advantages: In concrete terms, the design freedom of the complex geometries used in aviation is increased. At the same time, less material is consumed, which protects the environment and reduces costs. In addition, the use of additive processes makes it possible to economically develop and manufacture even smaller, more complex core engines with reduced pollutant and noise emissions.