A computational model for doctoring fluid films in gravure printing

Abstract

The wiping, or doctoring, process in gravure printing presents a fundamental barrier to resolving the micron-sized features desired in printed electronics applications. This barrier starts with the residual fluid film left behind after wiping, and its importance grows as feature sizes are reduced, especially as the feature size approaches the thickness of the residual fluid film. In this work, various mechanical complexities are considered in a computational model developed to predict the residual fluid film thickness. Lubrication models alone are inadequate, and deformation of the doctor blade body together with elastohydrodynamic lubrication must be considered to make the model predictive of experimental trends. Moreover, model results demonstrate that the particular form of the wetted region of the blade has a significant impact on the model's ability to reproduce experimental measurements.

Gravure-printed electronics: recent progress in tooling development, understanding of printing physics, and realization of printed devices

“…This discussion assumes a constant viscosity which is not necessarily the case due to the high pressures underneath the doctor blade. In the elastohydrodynamic regime both the viscosity of the fluid increases as well as the blade tip deforms under the load [32,33]. Thus, more careful tuning of the ink rheology and its behavior at high pressures by using different ink types such as nanoparticles or different polymer chain lengths can potentially lead to further improvements in wiping.…”

A review on in‐mold electronics technology

“…Inkjet printing : Inkjet printing is a digital printing process, heavily used for prototyping and large‐volume manufacturing of electronics. [ 78 ] Typically, the ink reservoirs of inkjet printers are coupled with piezo constrictors that load and expel ink. In this process, each droplet can be controlled, so the ink consumption is very low.…”

“…Then, the cylinder rolls over the substrate and the ink are transferred onto it (Transfer), creating the final pattern (Figure 11). [ 78 ] Once the substrate is wetted, ink spreads over it forming the final printed pattern (Spreading). For large‐area and high‐volume manufacturing, gravure printing is the great choice.…”

Investigating Porous Media for Relief Printing Using Micro‐Architected Materials

“…[ 7–10 ] This and other contact printing methods rely on intricate and dynamic fluid–solid interactions, demanding a more thorough understanding of precision application required for functional electronics, such as uniform thin films in organic photovoltaics and thin‐film transistors, along with well‐defined patterns for circuit metallization and micro‐electromechanical systems. [ 11–13 ] While traditional flexography plates are based on solid elastomers, recent work has revealed promise for advancing relief printing with more sophisticated material design. For example, capillary‐based contact stamps have been fabricated using mesoporous silica to achieve submicron patterning of fullerenes and polymers, [ 14 ] and further refined with porous polymers to achieve compatibility with the automated polymer pen lithography approach.…”