Numerical Analysis of Multilayer Forward Roll Coating

Abstract

Roll coating is at the heart of production of films which can be com posed of many layers To achieve a desirable coating thickness the operating parame ters, such as roll speeds, size and minumum gap width, have to be specified Due to the intractability of the problem by analytical methods, numerical techniques have to be used In the present work the Lubrication Approximation Theory (LAT) is employed and the solution is achieved by using a Newton-Raphson iterative scheme which determines both the unknown a priori flow domain and the interface locations for a combination of layers The analysis also provides the layer thicknesses after split ting, pressure distribution, separating force, torque, power consumption and temper ature rise. A parametric study based on the viscosity ratio for a double-layer sheet is presented.