Electrophotographic multi-material powder deposition for additive manufacturing

Abstract In order to realize multi-material components with Selective Laser Sintering (SLS) Technology new layer coating technologies are needed for the preparation of multi-material powder patterns. A promising technique to achieve such layers is electrophotography which is highly successful in the common printing industry. Due to its ability to handle different powders fast and precisely, the combination of electrophotography and SLS would support the progress in realizing high-quality multi-material parts. In this paper, electrophotographic polymer powder transfer for the preparation of multi-material layers is discussed with respect to the application in SLS. Therefore, a two-chamber design was built which enables the electrophotographic powder transfer under typical process conditions of SLS. Using this setup, the residual powder transfer of polypropylene powder was investigated in order to verify the 3D printing capabilities. Therefore, a scorotron unit was applied for charging the surface of already printed polymer layers, by which an electric field was established which transfers the powder adherent to the electrophotographic printing plate to the surface of the already printed polymer layers. The results show that the scorotron improves the uniformity of the powder deposition in comparison to a simple negative corona wire, and that the deposition quality depends on the scorotron grid voltage.