Additive Manufacturing (AM) has many advantages, yet the majority of parts have high surface roughness and porosity. The post processing of these parts is time consuming and often a significant cost factor for manufacturers. Technical coatings therefore open up new possibilities for the AM market, especially in industrial production.

To meet this challenge, two partners have investigated technical coatings for AM in a joint project: Sirris is an organisation focused on finding solutions for technological challenges, usually in projects with universities, research centres, associations and other institutions. Researchers at the Fraunhofer IAP, among other areas of expertise, have many years of experience in technical coatings.

With technical coatings, the Sirris and Fraunhofer researchers were able to significantly improve AM-produced parts regarding surface roughness and porosity. It turned out that the combination of lacquering and polishing is the most efficient technique for surface optimisation in AM. Sirris provided different components made with SLS, SLA, MJ and FDM. All methods pose different challenges to surface treatment.

"We analysed each part in the first step to determine specific properties,” explains Dr Andreas Holländer, expert in surface technology at Fraunhofer IAP. “Afterwards we were able to activate, paint and polish, and, in this case, metallise the respective surface with the appropriate method.

"It is important,” he adds, "that every part of the component’s surface has the required quality. In complex parts, some surfaces are difficult to reach. However, with the appropriate surface treatment technology, which in future will even be integrated into the AM machines, we are able to completely functionalise even complex components."