A multi-nozzle molten metal jetting printhead for high-throughput additive manufacturing

Molten metal jetting (MMJ) is an emerging metal additive manufacturing (AM) technology that shows considerable potential to achieve higher material deposition rates than incumbent AM technologies without any compromise in feature resolution. However, only single nozzle MMJ has been considered to date. Here, we introduce a novel multi-nozzle MMJ approach that dramatically increases print speed while preserving the achievable print resolution. We built and tested an 8-nozzle drop-on-demand MMJ printhead using a combined numerical and experimental approach. Our design achieves a 3 mm nozzle pitch by horizontally coupling the actuator to the nozzle through a fluid channel. CFD modeling showed that for every mm of channel length, ejected droplet velocity decreased by 0.036 m/s using a nominal waveform. Experimental testing showed that drop velocity deviation between nozzles could be reduced from 0.074 m/s to 0.0079 m/s by tuning the waveform amplitude for each nozzle. We achieved a peak deposition rate of 194 cm 3 /h. Our models show a 79% reduction in print time compared to single nozzle systems in a realistic part. The design methodology presented here can be scaled to any arbitrary number of nozzles needed to achieve target deposition rates with no loss of print resolution.