Drop-on-demand generation of aluminum alloy microdroplets at 950 °C using the StarJet technology

We present the drop-on-demand generation of liquid microdroplets from aluminum alloy melts with minimum diameters of 235 μm. The so-called StarJet technology, used to generate the droplets features a pneumatically actuated printhead that has been used to print microdroplets from solder (T
_melt
≈ 220 °C) before. In this work a novel StarJet printhead is presented that can be operated at up to 950 °C and thus allows for printing of aluminum alloys. The printhead is compatible with chemically aggressive metal melts and can be operated in a standard laboratory environment. Experimental results regarding the generation of droplets and a printed aluminum structure are presented. To the knowledge of the authors this is the first time that aluminum alloy microdroplets of such small size (d = 235 μm) have been produced by drop-on-demand.