Additive manufacturing of multi-material components in high volumes: paving the way for future applications

The GlobalAM project (grant number: 101138289), funded by the EU through Horizon Europe, has set itself a particularly ambitious goal. “With GlobalAM, we want to make laser powder bed fusion of metallic materials (PBF-LB/M) suitable for large-scale production. We want to accelerate a process that is used primarily for prototypes and small series in such a way that cycle times for series production are possible.” explains Dr. Frank Sarfert from Robert Bosch GmbH, who is also the lead partner in the project. In PBF-LB/M, a CAD model of the component to be manufactured is broken down into individual layers (slicing). A recoater is then used to spread the metal powder in thin layers to a building platform. The powder particles are melted by the laser beam corresponding to the contour extracted from the slicing process and join during the subsequent solidification. After a layer has been completed, the build platform is lowered, a new layer of powder is applied, and the process is repeated. As a result, the melted contour in the new layer joins with the contour below it. The component is built up in this way, layer by layer, from bottom to top. Although the process enables the production of complex geometries, it has not yet been introduced to the mass market due to high cycle times and uncompetitive product precision and quality. “We want to develop the PBF-LB/M process to such an extent that we can build defect-free cooling structures on power electronics components without post-processing,” adds the scientist.

After the official kick-off of the project on January 1, 2024, the mid-term meeting is now taking place at Robert Bosch GmbH in Renningen. All eight European project partners from Germany, Italy, Poland, Denmark and the Czech Republic will come together to present the project progress in each of the 10 work packages to the European Commission and to discuss the development work of the first 18 months.

To enable both well-founded research into the physical fundamentals and rapid industrial implementation of the ambitious project goals, partners from industry and science are working hand in hand in GlobalAM. The European project consortium is particularly pleased with the project’s first major milestones in research into the process-related interrelationships:

“We have developed multiple classes of models that allow us to calculate the morphology of the melt pool for different scenarios e.g. with or without powder, over inclined surfaces, keyhole situation, etc. (so-called melt pool models). In parallel, we have developed different process multi-scale approaches such as flash heating or agglomerated heat sources to enable prediction of thermal and mechanical conditions (residual stresses, deformation, etc.) over an entire part within an affordable timeframe needed for industrial partners (so-called part-scale models).” explains Prof. Mahamad Bayat from the Technical University of Denmark, describing the current state of modelling and simulation.

Johanna Zeisberg from the University of Kassel explains the state of the art in residual stress analysis as follows: “We employ various X-ray diffraction techniques and combine them to address the microstructural characteristics of PBF-LB/M components and to enable precise determination of residual stresses. A key objective of the project is also the fabrication of PBF-LB/M components on ceramic substrates. Due to the differing mechanical properties of the PBF-LB/M component and the ceramic, the residual stresses present in the ceramic are of particular interest as well. By utilizing different diffractometers, we are able to accurately determine the stress state within a defined depth in these materials."

“We are pleased that the project is currently on schedule and that initial findings have already been published in scientific journals,” says Dr. Torsten Hermanns of EurA AG, responsible for dissemination and exploitation.

Background:

GlobalAM is an acronym for ‘Enabling laser powder bed fusion for high precision mass production of multi-material components on dissimilar substrate materials’ and connects 8 partners from industry and science along the entire value chain. These include Robert Bosch GmbH (Germany), the University of Kassel (Germany), EurA AG (Germany), the Technical University of Denmark (DTU), Amazemet (Poland), Safina (Czech Republic), Politecnica di Milano (Italy) and Prima Additive (Italy). The project will run for three years, and the EU funding amounts to around 4 million euros. Further information on the project is available under the Grant Agreement number 101138289 or at www.globalam-project.eu.