Technical Coatings for Additive Manufacturing Show Promising Results

Researchers from the Belgian NPO Sirris and the Fraunhofer Institute for Applied Polymer Research (IAP) partnered to investigate technical coatings for additive manufacturing (TCAM) to rectify the surface roughness and porosity often found in fabricated components.

“Today, with the transition from rapid prototyping to industrial production, the demands on AM-manufactured components are growing. Being able to warrant consistent material quality is essential for industry producers. In addition, demands on the surface quality are growing,” says Dr. Andreas Holländer, expert in surface technology and leader of the research group at the Fraunhofer IAP.

Sirris provided different components made with selective laser sintering (SLS), stereolithography (SLA), material jetting (MJ) and fused deposition modeling (FDM), and then metallized the smoothed components. All methods pose different challenges to surface treatment, according to the researchers.

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 optimization in additive manufacturing (AM). In addition, using special lacquers or surface treatments can add more functionality to the components. Improved scratch resistance, antimicrobial properties and many more features are applicable.

“With years of expertise in surface treatment, we are able to meet a wide range of requirements. We analyzed each part in the first step to determine the specific properties. Afterwards we were able to activate, paint, and polish and, in this case, metallize the respective surface with the appropriate method,” says Holländer.

Patrick Cosemans, team leader of the Smart Coating Application Lab at Sirris Flanders says: “If we only polish our finished components, it takes a long time, and especially with fine, detailed features, we change their shape. It comes to abrasion, which we want to avoid. With the Fraunhofer IAP we have developed possibilities to overcome the current problems, especially the porous and rough surface, in additive manufacturing.”

“It is important,” says Holländer, “that every part of the component’s surface has the required quality. In complicated parts, some surfaces are difficult to reach. With the appropriate surface treatment technology, which in future will even be integrated into the AM machines, we are able to functionalize even complex components completely.”