Experimentally probing the extremes of droplet-on-demand printability via liquid metals

Abstract

The liquid metal jetting droplet-on-demand technology provides many potential benefits to metal additive manufacturing. However, much is left to understand the operational margins to reliably create stable, satellite-free droplets. We elucidate these margins by experimentally probing the unexplored extremities of a recently proposed printability window based on the jet Weber (Wejet) and Ohnesorge (Z = 1/Oh) numbers. We generated stable droplets for 2 ≲ Wejet ≲ 4 for all tested Z = 339 to 2526 - well beyond the bounds of any previously published printability window - suggesting that additional physics may be needed to understand droplet-on-demand in the high Z regime.