Direct-write deposition of fine powders through miniature hopper-nozzles for multi-material solid freeform fabrication

In this paper, we present a concept for multi-material solid freeform fabrication of heterogeneous components. This concept features hopper-nozzles designed for depositing thin layers of multiple patterned materials followed by selective laser sintering for consolidation to desired densities. Although prior work on the design of small-scale nozzles for powder delivery is lacking, our design is guided by background theory for particle flow through industrial hoppers. Experimental guidelines for the delivery of powders in the 10 to 125 mum range from 0.5 to 2 mm hopper-nozzle orifices are presented.