A versatile 3D-printed droplet-on-demand generator

There is a rapid and persistent growth in the study of dynamical behavior of droplets, however, the precise generation of these droplets over a range of sizes can be challenging. A versatile 3D-printed droplet-on-demand generator is presented for laboratory use. The design is modeled off of an existing design [Harris et al., Experiments in Fluids, 56:83 (2015)] but is tested with an extended range of working fluids and the manufacturing process is greatly simplified by 3D-printing the principal components. The present device is tested with deionized water and water-glycerol mixtures, and was reliably able to produce single droplets-on-demand of diameters 0.65-1.32 mm with an overall variability of less than 1%. Tips for fabrication, operation, and maintenance as well as potential applications will be discussed throughout.