Andreas Holländer

Additive manufacturing (AM) technologies are recognized as promising new approaches for the production of industrial goods. One of the major drawbacks, however, is the surface quality of parts prepared by AM. In the present paper, the potential of applying classical surface technology to efficiently improve the surface properties of AM products is explored. The surface properties of parts produced by different AM technologies were investigated and showed rather large variations between various spots at the surface. Low‐pressure plasma, as well as flame treatment, were found to provide a good activation also of the porous surfaces of parts prepared by selective laser sintering of PA12 (polyamide). Lacquering was found to tremendously reduce the roughness of AM products. The best results were obtained by the combination of lacquering and polishing of lacquers, which are optimized for polishing.

Polyethylene (PE) films were treated with flame pulses for a confined activation of the surface. Acetylene, ethene, and butane were used in various mixing ratios with oxygen. The gas mixture was fed through a 0.5 mm stainless steel capillary, which was placed close to the surface of the film. An electrical spark was used to ignite the gas. A single flame pulse suffices to oxidize the polymer surface to an oxygen concentration of 26 at% (XPS). The profile of the oxygen concentration was analyzed by XPS and revealed full width at half maximum values down to 2.8 mm. The treatment of pieces of sintered PE powder (nominal pore size, 80 µm) showed that the surface oxidation penetrates several millimeters into the pore system.