Metal Additive Manufacturing Conference - MAMC 2020

Laser Powder Bed Fusion (L-PBF) is an additive manufacturing process for the production of complex high quality metal parts. The surface roughness has an important impact on the mechanical behavior like crack initiation or fatigue life. Especially for complex geometries with its large amount of internal surfaces it is not possible to improve all surfaces by post-processing or even to determine the surface roughness non-destructively. In this study, a non-destructive testing method is presented to determine the as-built surface roughness independent of size or geometry of the part. A fast-curing thixotropic 2-component-silicone was used to produce replicates of the surfaces of as-built Ti-6Al-4V samples. These replicates represent a negative print of the original surface so that the surface roughness can be measured indirectly with a confocal laser scanning microscope. This method was validated using a set of additive manufactured samples with different surface roughness generated by different angles to the build platform where the original surface was compared to the replica. The results show that differences in surface roughness can be measured and the limits of this method are determined.