Factors Influencing Web Wrinkling in Roll-to-Roll Coating Production Systems

The web-wrinkle phenomenon always occurs in the roll-to-roll coating production process, which leads to the decline of coating quality and an increase in waste. A theoretical analysis of the phenomenon is presented, and a simulation research method is proposed for the study. The method is outlined as follows: Initially, the web’s surface on the guide roll is modeled as a thin shell, with the relationship between web displacement and strain established through the nonlinear large deflection theory. The differential equations of the web are derived based on the internal-force equilibrium relationship. Subsequently, the boundary conditions are established according to the transfer of the web on the guide roller’s surface, and the deflected surface functions satisfying these conditions are obtained. The static method was used to determine the critical load for a web wrinkle, considering the friction between the web and the guide roll. Finally, finite element simulation analysis was conducted to ascertain the factors affecting the critical wrinkling load of the web. Through the analysis, the accuracy of the formulas used to calculate the critical compression load of the web was determined. The critical wrinkling load increases with the web thickness, web tension, and modulus of elasticity. The critical compressive stress of a web wrinkle was found to be proportional to the web thickness, modulus of elasticity, tension, and coefficient of friction. The rational selection of these parameters provides a theoretical foundation for improving the quality of coating production.