https://doi.org/10.1140/epjs/s11734-024-01397-8
Regular Article
Characterizing start and end edges in intermittent slot coating processes via coating bead flow dynamics
Department of Chemical and Biological Engineering, Korea University, 02841, Seoul, Republic of Korea
Received:
28
July
2024
Accepted:
5
November
2024
Published online:
26
November
2024
The relationship between the coating bead flow dynamics and the profiles of patch coating films in intermittent slot coating processes was investigated using two-dimensional numerical simulations. In the continuous production of discrete coating patches, the start (rising) and end (falling) edges in the flow direction must be precisely analyzed, considering the liquid’s rheological properties and the residual liquid remaining in the coating bead region between on–off flow control stages. The residual volume, which significantly affects both the start and end edges for Newtonian and non-Newtonian liquids, was found to remain in the coating bead region only above a certain capillary number (Ca) of 0.1, with an increasing trend as Ca increases. The growth of the start edge height of coating patches was greatly influenced by the residual volume. In contrast, the end edge length was inversely proportional to the residual volume concerning Ca. Furthermore, for shear-thinning liquids with various power-law indices (n), a certain Ca value, similar to that for the Newtonian case, was confirmed to induce the occurrence of residual volume.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
