Flow Visualization of Film Coating Process

Abstract

Film Coating is one of the most widely used techniques for producing photo-sensitive materials, magnetic tapes, etc. The curtain coating process is one of those techniques utilizing a free falling liquid curtain between a pair of guide plates. This method has several merits such as less consumption of coating liquid, post measuring and non-smell process, etc. It is most important to analyze precisely the velocity field of the curtain in order to keep the whole process stable.
In this study, curtain coating is analyzed using hydrogen bubble method. From the timeline of bubbles, the velocity field and acceleration together with the boundary layer along the guide plate are measured. The influence of liquid viscosity on these parameters are mainly considered.