Analytical study of isothermal blade coating process using Rabinowitsch fluid model

Abstract

Blade coating process is widely applied in the industry for its practical applications in photographic films, paint industries, and magnetic storage devices. Also for manufacturing newspaper, metal coating, electronic circuit boards, and textile fibers. The blade coating process passes a fluid into the gap between the moving substrate and blade. This study uses the Rabinowitsch model which represents the Newtonian, shear thickening, and shear thinning effects by changing a non-linear parameter. Lubrication theory is used to simplify the dimensionless governing expressions. Then perturbation technique is used up to second order to solve the resultant system and validated by the numerical shooting technique. The graphs and tables present how the non-linear parameter affects the dimensionless velocity, pressure profile, coating thickness, and blade load. The non-linear model parameter proves to be the controlling parameter for the coating thickness, blade load, and pressure distribution, helping in determining the coating efficiency and improving the substrate life. This paper provides the theoretical framework for engineers to be applied in many industrial applications. In future, further validation of results can be done through experiments.

Theoretical Analysis of Roll-over-web Coating of a Non-Newtonian Polymer Using Lubrication Approximation Theory

“…Zaheer and Khaliq 31 investigated a water based nanofluid with Cunanoparticles to study non-isothermal calendaring process. The theory of blade coating and forward roll-coating are discussed in detail by several authors [32][33][34] using different non-Newtonian fluids. They successfully applied the lubrication approximation theory in their analysis to simplify the governing differential equations.…”