An Analysis of Pinned Edge Layer of Slot-Die Coated Film in Roll-to-Roll Green Manufacturing System

Roll-to-roll slot-die manufacturing of soluble materials with a uniform layer is a critical step in realizing low-cost and eco-friendly printed electronics for solar cells and batteries. This study presents an analysis of the lateral thickness of a coated layer that consists of a fluid with a high viscosity produced by using a slot-die roll-to-roll system with specific attention focused on a pinned edge phenomenon exhibited in the coated layer. A solution viscosity of 832 mPa·s is used and includes relatively high capillary numbers in the experiment in the range of 0.47–3.47. The purpose of the study included analyzing various forces around the coating nozzle and determining the correlation between forces by using dimensionless numbers. Computational fluid dynamics analysis and experiments were performed to obtain various parameters in terms of these dimensionless numbers. The experimental results suggest that the pinned edge should be reduced below 10% by reducing the coating gap parameter that represents the gravity forces.