Electrophotographic Powder Application for Metal Powder bed based Additive Manufacturing

Abstract

The scope of this paper is the systematic investigation and conceptual design of a process based on the principle of electrophotography for the application of particles on a build plate with the focus on powder bed based fusion of metals by means of a laser beam (PBF-LB/M). The influence parameters for the particle transfer from the photoconductor to the build plate are investigated using a prototype based on the stamp principle. In this setup the process is extended for the first time by the sequence of powder deposition compared to [1, 2]. The investigations of this work concentrate exclusively on a full-area attraction on the photoconductor´s surface and its deposition. The attraction of the powder to be deposited is performed without an exposure sequence. Significant parameters for the system are identified and measures to ensure a reproducible deposition are derived. Within the scope of experimental investigations, the PBF-LB/M typical powder 1.7147 (20MnCr5) with a particle size distribution of 15 to 56 µm is tested with regard to the deposition quality (surface coverage density and layer thickness) in a single- and multi-layer deposition. The stacking of the particle layers not only increases the area coverage density, but also demonstrates the basic transferability for generating a powder bed, which is required for additive manufacturing.