The long lead time of turbine blades and vanes presents a big challenge to the validation of new part designs in engine tests. Conventional vane production through casting is unsuited for the fast iteration cycles required today in the development of hot path components. In a joint project, Siemens and the Fraunhofer Institute for Laser Technology ILT have now developed a faster production process based on selective laser melting (SLM). Components are manufactured in a modular way in the new process chain, resulting in additional benefits.
Last year, Siemens commissioned its Clean Energy Center, a new combustion test center in Ludwigsfelde near Berlin. The center plays a major role in developing and refining gas turbines as a facility for conducting realistic tests on various turbine components with liquid or gaseous fuels. Rigorously optimizing the combustion processes involved is the key to achieving greater energy efficiency in the turbines.
Guide vanes made using the new modular process chain (material: Inconel® 718).
Fraunhofer ILT, Aachen, Germany.
During the tests, individual turbine parts are exposed to temperatures of 1500 degrees Celsius or more. Such components are usually manufactured from superalloys in a precision casting process, in which each iterative loop may last several months and incur significant costs. Thus far, this has severely curtailed the number of tests possible.
Fast prototype production with additive laser techniques
Experts from the Siemens gas turbine manufacturing plant in Berlin and the Fraunhofer Institute for Laser Technology ILT in Aachen, Germany, have now developed a laser-based technology that considerably speeds up the manufacturing process for turbine vanes slated for the hot gas area of the engine.
To withstand the high temperatures over long periods of time, the turbine vanes require complex internal cooling structures. Selective laser melting (SLM) has proven itself to be up to the challenge, especially for prototypes or small batches featuring complex geometries. Similar to using a 3D printer, special alloys are melted by laser on a powder bed. The components are then built up layer by layer.
Over the past several years, Fraunhofer ILT has built up considerable expertise in the use of additive laser techniques and alloys for components exposed to high temperatures. With this wealth of experience, the scientists were able to develop special processes that made it possible to produce the relatively large parts (up to 250 mm) at Siemens with a high degree of dimensional accuracy and superior surface quality.
New production chain uses modular design for turbine vanes
Securely mounted on the turbine housing, guide vanes channel the hot gas to the movable rotor blades. The guide vanes consist of two massive platforms plus an airfoil with a delicate cooling structure. The latter presents a major manufacturing challenge; even production using SLM required additional internal supports.
A modified process chain has solved the problem: the platforms and the airfoil are manufactured separately and then subsequently brazed together. This makes it possible to not only eliminate the supports in the blade, but also to improve the surface quality. The result is a fully functional component that can be used in hot path rig testing in order to deliver quick feedback to the design engineers.
Siemens optimized various production steps in preparation for this idea. After manufacturing via laser, the parts are precisely measured, subjected to finishing, and then joined using high temperature brazing.
This modular production of turbine blades offers significant potential for other components as well. It would make it possible to connect cast and SLM-made parts, leaving just the complex or variable parts to be produced using SLM. At the same time, it would also facilitate the production of parts with difficult geometries that are currently too large for the SLM process.
Dipl.-Ing. Jeroen Risse
Group Rapid Manufacturing
Telephone +49 241 8906-135
Dr.-Ing. Wilhelm Meiners
Group Manager Rapid Manufacturing
Telephone +49 241 8906-301
Fraunhofer Institute for Laser Technology ILT
52074 Aachen, Germany
Petra Nolis | Fraunhofer-Institut für Lasertechnik ILT
It Takes Two: Structuring Metal Surfaces Efficiently with Lasers
15.03.2017 | Fraunhofer-Institut für Lasertechnik ILT
FOSA LabX 330 Glass – Coating Flexible Glass in a Roll-to-Roll Process
07.03.2017 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
22.03.2017 | Materials Sciences
22.03.2017 | Physics and Astronomy
22.03.2017 | Materials Sciences