Frankfurt / November 16, 2021 - November 19, 2021
Fraunhofer Joint Booth
Fraunhofer Joint Booth
Conventional systems for Laser Powder Bed Fusion (LPBF) are limited in their size. When increasing the usable build-volume, the challenge is to realize a homogeneous shielding gas flow over the entire powder bed. In addition, an increase in productivity is necessary in order to be able to use such systems economically.
To meet these challenges, the Fraunhofer Institute for Laser Technology ILT has developed a novel LPBF machine concept (size: 1000x800x350mm³) for the production of large components as part of the lead project futureAM. This concept includes a processing head which is movable via linear axes. The processing head features a local inert gas system, thus creating process conditions which are easy to control. The latest development stage includes a processing head with a five-scanner system to ensure sufficient productivity of the process.
For the proof of concept, Rolls Royce Ltd. provided an oil transfer coupling of an aircraft engine as a demonstrator and redesigned it for additive manufacturing. With the help of the new machine concept, it was possible to manufacture the demonstrator with a bounding box of Ø620 x H280 mm³. The monolithically manufactured component thus replaces an assembly of originally 44 individual parts.
The collection of component condition data such as thermal and mechanical stress forms the basis for predictive maintenance, Big Data and AI approaches. For this purpose, components must be equipped with suitable sensors. Additive manufacturing methods such as laser powder bed fusion (LPBF) offer a wide range of possibilities for producing application-adapted components. Laser-based coating approaches, on the other hand, can be used to additively manufacture sensors directly on component surfaces, e.g. through the wet-chemical deposition of electrically insulating and conductive materials; subsequently laser radiation is used for thermal post-treatment of the printed layers.
Fraunhofer ILT combines these additive manufacturing methods to equip printed lightweight components with printed sensors. To additively attach the sensors, the researchers at Fraunhofer ILT print the necessary layers and structures made of different materials directly onto the component layer by layer and then functionalize them using laser radiation. In the case of strain gauges, the insulation layer, the measuring grid and the encapsulation are applied one after the other. For sensor integration into the interior of the component, the LPBF process is stopped, the sensor is applied layer by layer and the LPBF process is then continued. The wireless telemetry system on a compact circuit board is finally attached to the component and connected to the electrical contact pads.