Theoretical modeling of key parameters of wet film in roll coating process of coating panel

The purpose of this dissertation is to quantitatively regulate the wet film thickness of coating panels in metal packaging during roll coating, which has not been accomplished in previous studies. The aim of the research is to derive a formula model for the roll coating machine, which is a general-purpose equipment, to provide theoretical support for quantitatively regulating wet film thickness and calculating leveling time. Based on the coating leveling formula studied by Orchard [Appl. Sci. Res. 11, 451 (1963)], combined with the working conditions of the roll coating process, an innovative application of boundary slip theory and Hertzian theory is used to analyze the functional relationship of each parameter in the roll coating process, and to construct a model of wet film leveling time. The process data were obtained from factory equipment. The validation of the formula model refers to the method adopted by Wang and others, who processed experimental fixtures with different wavelengths and crest heights to experimentally validate the model. The average thickness of the wet film and the leveling time are the key to the roller coating process. The average wet film thickness is the key parameter affecting the quality of the product, and the leveling time determines when the wet film enters the dry film process. The wet film thickness mainly depends on the pressure of each roll in the roll coating process. The wet film leveling time model accurately constructs the functional relationship between process parameters, leveling time, and wet film thickness, which can be quantitatively calculated. The leveling time model is experimentally verified to be correct.