SKZ, Fraunhofer IAP Develop New Types of Powder for 3D Printing

The SKZ Plastics Center and the Fraunhofer Institute for Applied Polymer Research IAP have launched the “capSLS” research project. The aim is to significantly expand the range of powder materials for 3D printing by adding encapsulated additives. The selection of suitable materials in this area is still very limited.

Additive manufacturing has become standard in industrial product development. In addition to the right manufacturing and production method, tailor-made materials are a decisive factor for successful products.

However, the choice of materials for powder-based 3D printing is still limited. The Fraunhofer IAP and the SKZ Plastics Center have set themselves the goal of significantly expanding the range of powder materials by adding additives in order to further exploit the technological and economic potential of this technology.

Powder-based 3D printing – known as powder bed fusion laser-based (PBF-LB) or more commonly as selective laser sintering (SLS) – uses a laser to melt a plastic powder locally and build the part in thin layers in a build space. The powder must have a variety of properties.

“This is where the challenge lies, because when additives are incorporated into the powder (grain), they change the bulk properties and the overall property profile, often making processing impossible. Our extensive research will determine which additives can be incorporated and how. Two innovative powder production processes are also being developed in this context,” said Patrick Limbach, materials developer at SKZ.

As a first step, the research team is systematically testing which commercial and self-developed polymer additives are fundamentally suitable for powder preparation and the printing process. Fraunhofer IAP is contributing its extensive expertise in microencapsulation.

“We examine properties such as particle size, surface properties, thermal stability and filling level and test the limits of what is possible. In the second step, we use our specially developed microcapsules,” noted Dr. Alexandra Latnikova, a specialist in microencapsulation at the Fraunhofer IAP.

“We give the materials many intelligent functions,” said Limbach. “For example, microencapsulated dyes can indicate defects in printed components because the color is released when the capsules in the material are damaged. Encapsulating flame retardants would also open up a wide range of applications. In a previous project, we successfully demonstrated that microencapsulated lubricants can impart self-lubricating properties to injection molded and FLM-printed components. This can reduce the material wear normally caused by friction on components by up to 85 percent. We are now transferring these results to powder 3D printing.”