Fraunhofer Institute for Microstructure of Materials and Systems IMWSManufacturing large-format plastic components via 3D printing using granules offers numerous advantages. As part of the “AddiQ” project, the Fraunhofer Institute for Microstructure of Materials and Systems IMWS has developed quality assurance solutions that are implemented during the manufacturing process. Sensors, automated nozzle evaluation, and test specimen concepts link process data with component properties. This lays the foundation for more cost-effective and traceable manufacturing processes, such as for replacement parts in the transportation sector.
Rail vehicles are often in service for several decades. However, individual components such as seat shells, trim panels, or exterior parts wear out sooner. For such components, replacement parts may no longer be available, while conventional remanufacturing in small quantities is often labor-intensive and expensive. Additive manufacturing opens up the possibility of producing replacement parts on demand, thereby supporting availability in the transportation sector.
The Fraunhofer IMWS pursued such approaches in collaboration with SLV Halle GmbH, the IKTR (Institute for Plastics Technology & Recycling e.V.) in Weißandt-Gölzau, and studio.201 software GmbH in Magdeburg. As part of the “Quality Assurance in Additive Manufacturing (AddiQ)” project, the consortium focused on a process known as Fused Granulate Fabrication (FGF). Unlike filament printing, this process uses plastic granules. The method offers potential for higher material throughput and cost-effective manufacturing, particularly for large components. “3D printing with granules is more productive, faster, and therefore more cost-effective,” explains Thomas Wagner, who led the subproject at Fraunhofer IMWS.
To fully realize the technology’s potential, robust methods are needed to ensure the desired component quality. To this end, Fraunhofer IMWS equipped a Yizumi granulate printer with sensors to measure acceleration, ambient temperature, granulate temperature and humidity, melt pressure, and the mass on the build platform. All these parameters influence layer adhesion, geometry, and mechanical properties. The challenge, therefore, was not merely to collect process data. The key was to reliably link measured values to the resulting component quality using appropriate testing concepts.
In addition, the team developed a retrofittable retract system and an automated image analysis system for printer nozzles. These tools enable the detection of wear and allow for better estimation of future maintenance needs. The institute thus combined its expertise in process monitoring, testing methodology, and material characterization. “Based on our results, manufacturers of materials and components – as well as machine manufacturers – can learn about methods for evaluating the quality of 3D-printed components, test their own materials, and produce reference prints,” says Wagner.
The “AddiQ” approach supplements the established testing of finished components with data directly from the printing process. This allows deviations to be detected earlier; at the same time, it lays the groundwork for more targeted process control and predictive maintenance. For companies, this means greater transparency in the development and evaluation of manufacturing processes in granulate 3D printing.
A 500-millimeter-long ICE front apron, scaled down to 38 percent of its original size, served as a demonstrator. The original component measures 1,300 millimeters and exceeds the build volume of the printing system used. The results show how sensor technology and testing methods can be applied to other large-format replacement parts for rail vehicles in the future. The next step is to work with industry partners to apply the developed methods to specific customer components and qualify them for their respective applications.
(October 15, 2026)