Nowadays, a wide range of industrial manufacturing processes require high precision micro dispensing to print materials on a variety of substrates. Micro dispensing is concerned with jetting of liquids through nozzles with a typical diameter on the order of magnitude of 100 microns. In this work, we study various aspects of micro dispensing of a Newtonian liquid ranging from jet break-up to the (equilibrium) profile of a printed line on a substrate. Contrary to the investigations of others, our work is concerned with jets that have very high Froude (Weber) numbers. We use dimensional reasoning, along with experiments, to infer phenomenological correlations between the liquid properties, dispensing conditions and the jet break-up ratio. These correlations are used to create maps for stable dispensing regimes. Furthermore, when the liquid is dispensed from the micro nozzle, the jet diameter usually contracts over the jet length. We modify an analytical solution of the Navier-Stokes equation, valid to describe the shape of gravity-driven jets, to obtain a correlation for inertia-driven jets. Finally, we extend a correlation that describes a cylindrical cap to obtain the three-dimensional profile of a liquid that is printed on a flat substrate and compare it with experiments. Comparison of experiments and theoretical prediction shows a very god agreement.


Micro Dispensing of Liquids for Material Printing: Stability and Shape of Laminar Jets With High Froude Numbers

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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