A High-Fidelity Modeling Framework for Near-Field Electrohydrodynamic Jet Printing

Electrohydrodynamic jet (e-jet) printing is a high-resolution, jet-based micro-additive manufacturing process that has gained momentum in many applications such as printed electronics. However, there are limited works in the literature that have modeled the e-jet process due to its multi-physics and multi-phase nature. This work presents a high-fidelity, two-phase framework for the high-resolution e-jet printing process based on the leaky-dielectric model and two-phase flow (liquid-air). The level set method is used to track the ink-air interface, as a suitable choice for high-resolution two-phase processes. We have developed the model in COMSOL Multiphysics, where we relaxed some of the prior art’s assumptions, including that of a constant flow rate to the nozzle inlet, which is typically not accurate for the e-jet process at high-resolution. The simulation is conducted for a conventional near-field e-jet setup and the results successfully demonstrate the critical process steps including equilibrium, Taylor Cone formation, and the creation of a jet. Moreover, to evaluate the model, the effects of different material properties such as surface tension, viscosity, and relative permittivity on the e-jet process are simulated and discussed.