Effect of slot-die configurations on coating gap dependence of maximum and minimum wet thicknesses

The dependence of the maximum and minimum wet thicknesses on the coating gap is derived for the slot-die coating process, under different slot-die configurations. Analytical expressions for the wet thickness and its derivative with respect to the coating gap are obtained using a simple flow model. The results indicate that, as expected, the minimum wet thickness increases linearly with the coating gap; however, the maximum wet thickness demonstrates a counterintuitive trend of decreasing as the coating gap increases, when a specific slot-die configuration is assumed. Moreover, the results are also validated by numerically solving the complete two-dimensional (2D) Navier-Stokes equation.

Automated summary

This study investigates the influence of the coating gap on the maximum and minimum wet thicknesses in slot-die coating process, and establishes a simple flow model with analytical expressions. The results show that the minimum wet thickness increases linearly with the coating gap, while the maximum wet thickness exhibits a counterintuitive trend of decreasing with the increasing coating gap under a specific slot-die configuration.