TY - JOUR A1 - Stichel, Thomas A1 - Laumer, Tobias A1 - Linnenweber, Tim A1 - Amend, Philipp A1 - Roth, Stephan T1 - Mass Flow Characterization of Selective Deposition of Polymer Powders with Vibrating Nozzles for Laser Beam Melting of Multi-material Components JF - Physics Procedia N2 - The generation of multi-material components by laser beam melting (LBM) is a challenge which requires the invention of new coating devices for preparation of arbitrary powder patterns. One solution is the usage of vibration-controlled nozzles for selective deposition of polymer powders. Powder flow can be initiated by vibration enabling a start-stop function without using any mechanical shutter. In this report, the delivery of polymer powder by vibrating nozzles is investigated with respect to their application in LBM machines. Therefore, a steel nozzle attached to a piezo actor and a weighing cell is used in order to measure the stability and time-dependence of the powder mass flow upon vibration excitation with the usage of different kind of powder formulations. The results show that precompression of the powder inside the nozzle by vibration excitation is essential to realize a reliable start-stop function with reproducible discharge cyles and to prevent a initial flush of powder flow. Moreover, the use of different powder materials showed that mass flow is even possible with powders which are not optimized regarding flowability, but is readily enhanced with a factor of 2 to 3 by admixing AerosilĀ® fumed silica. KW - laser beam melting KW - multi-material deposition KW - polymer powder KW - vibration-controlled powder nozzle Y1 - 2016 U6 - https://doi.org/10.1016/j.phpro.2016.08.099 SN - 1875-3892 SN - 1875-3884 VL - 83 SP - 947 EP - 953 PB - Elsevier CY - Amsterdam [u.a.] ER -