An Empirical Study of Jetting Dynamic in Electrohydrodynamic Jet Printing

Electrohydrodynamic jet (e-jet) printing has emerged as a promising technique for precise and high-resolution additive manufacturing. However, the dynamic behavior of the jet during printing, particularly the occurrence of transitional behaviors between Continuous Jet and Pulsating Jet modes, known as Natural Pulsation Initiation (NPI), poses challenges in controlling printing speed and quality. In this study, we investigate the NPI behavior of the cone-jet mode in e-jet printing, focusing on its modeling and characterization. Through experimental investigation involving 15 different liquids with varying material properties and applied potentials, we capture high-speed recorded videos to analyze the jetting dynamics. Our methodology involves calculating and modeling the flow rate of each experiment as an exponentially decaying function, enabling the extraction of time constants for these decaying functions. We develop two fitted models for the time constants of NPI and Continuous Jet (CJ) modes as a function of dimensionless voltage. Notably, our findings reveal an approximate boundary limit between NPI and CJ modes, offering valuable insights for predesign considerations of e-jet printing processes. Copyright (c) 2024 The Authors.