Research on the printing mechanism of electrohydrodynamic satellite-free droplets in pulsed voltage

Abstract

Electrohydrodynamic (EHD) drop-on-demand (DOD) printing in pulsed voltage is a very promising technology for additive manufacturing at the micro- and nanoscale. However, jet/meniscus retraction during DOD printing creates additional satellite droplets, which can lead to blurred print patterns and thus reduced print resolution. In this paper, the mechanism of satellite droplet formation in EHD DOD printing in pulsed voltage is investigated in detail for the first time. At first, the numerical model for EHD printing is established and the correctness and credibility of the numerical results are verified experimentally. After that, the three key operating parameters peak voltage, voltage duration, and bias voltage are analyzed in detail on the formation mechanism of satellite droplets. The operating phase diagram without satellite droplets is proposed. Finally, the electric Bond number BoE and Ohnesorge number Oh are proposed for the detailed analysis of the physical parameters of the liquid on the generation of satellite droplets, and the prediction model of satellite droplet size is presented. The mechanism of satellite droplet formation in EHD printing is revealed, which provides a theoretical basis for the stable printing of satellite-free droplets and advances its application in high-resolution additive manufacturing.