Together with the H+E-Produktentwicklung GmbH in Moritzburg, Saxony, Germany, the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) in Dresden, Germany, has developed a fully-functional, true-to-scale gas turbine which demonstrates the current potentials and limitations of powder bed-based Additive Manufacturing technologies.
The demonstrator ‘Siemens SGT6-8000 H’, a 1:25 scale model of a gas turbine for power generation, was completely manufactured with additive processes in all areas except for the shaft. The component assembly consists of sixty-eight parts made of aluminium, steel and titanium, which through component optimisation and the possibilities of Electron Beam and Laser Powder Bed Fusion (EB-PBF and L-PBF) technologies replace the almost 3000 individual parts that make up the original component.
Fraunhofer IFAM was involved in the manufacturing of the component as well as the data modification for the technology-adapted production. The housing components, with stator stages, were manufactured directly on site at the Innovation Center Additive Manufacturing ICAM® in Dresden using EB-PBF of Ti-6Al-4V in a GE Additive Arcam EBM Q20+ machine. The turbine stages and the other housing components were manufactured at H+E using L-PBF.
According to Fraunhofer IFAM, the production planning stage was particularly important and accordingly complex to determine the right technology for each component. The accuracy and roughness of the surfaces, for example, had to be taken into account, as well as the necessity and number of support structures and the component size had to be considered.
The functionality of the demonstrator was a prerequisite for all considerations. For example, the shaft and turbine stages had to be able to rotate freely between the stator stages and the individual components of the demonstrator had to be connected to each other with minimum effort – by screwing and plugging on.
The components were modified constructively in order to be able to manufacture the turbine ‘first time right’. For example, it was made possible to manufacture the 316L housing segment by L-PBF without support structure.
The combination of different materials commercially available from the respective plant manufacturers is also demonstrated in the component. Not all processed materials correspond to the target materials for turbines; this is due to the fact that these materials cannot yet be processed in such a way as to be offered commercially.