Numerical simulation to predict printed width in EHD inkjet 3D printing process

Electrohydrodynamic (EHD) inkjet printing is defined as a micro-scale, economical, direct-write, and an effortlessly manipulative technique for the manufacturing of high-accuracy three-dimensional (3D) patterns without an affinity for molds or photomasks. EHD printing is characterized by the creation of the stable Taylor cone. At some point in time the cone releases inkjet for the printing to commence. Printed width (which is proportional to the jet thickness) in 3D printing can straightforwardly influence the accuracy and precision of the printed structure when EHD inkjet printing is used for planning and fabrication of small size utilitarian designs. In any case, printed width cannot be adjusted straightforwardly like the operating parameters involved in the phenomenon. Therefore it is important to examine what these operating parameters mean for jet thickness for scrutinizing high-resolution patterns. In this paper, a numerical model has been proposed to determine the influence of applied voltage, nozzle-inlet velocity, and standoff height (distance from nozzle to ground electrode) on the diameter of the printed lines. Simulation results are analyzed to determine the most desirable value of the operating parameters. The most desirable value refers to the parameter magnitude at which the thinnest printed width is obtained. The model illustrates the continuous jetting mode of EHD printing. The simulation was completed using the COMSOL Multiphysics 5.6 simulation package in which the Laminar and Electrostatics modules are used to effectively couple the electric and hydrodynamic fields followed by the usage of the level set approach to track the air-liquid phase boundary. A proper stable Taylor cone was generated using proper boundary conditions and suitable parameter magnitudes followed by the continuous jetting phenomenon. Once the theory of the Taylor cone is established, simulations are performed by modulating the parameters one by one, during which the other parameters are kept fixed. Ramifications reflect that the thickness of the imprinted lines improves along the increase in nozzle-inlet velocity while it decreases with standoff height. Jet thickness shows increment with sufficiently large applied voltages. In addition, the optimal value of the parameters are highlighted. The best printing results are obtained at those values. The simulation repercussions are in unison with the theories of EHD. The created numerical model has permitted us to assess the impact of these intervening parameters and would be boosting condition improvement for executing sturdy electrohydrodynamic inkjet micro-level 3D printing in cone jet modes. Copyright (C) 2022 Elsevier Ltd. All rights reserved.