Trajectory analysis of the charged droplet during electrohydrodynamic jet printing

Electrohydrodynamic (EHD) jet printing is a promising direct writing method to produce micro- and nano-scale dots due to its easy manipulation, high resolution, and low cost. The effect of printing conditions on the diameter of printed dots was widely studied by both experiments and simulations. However, positional precision is also important for EHD printing. There is no published work on numerical simulation for the trajectory analysis of the ejected droplet. In the present work, a finite element model was established to investigate the droplet trajectory. The influencing factors, such as nozzle size, nozzle angle, applied voltage, ink density, and charge number in one droplet, were considered during numerical simulation. The influence of influencing factors on the electric intensity, droplet speed, and deposition direction was analyzed. The proposed simulation model provides a useful tool to analyze the droplet formation process and optimize the printing parameters to improve the positional precision of EHD printing.