Intermittent Coating

摘要

The world has gone patch coating crazy! Batteries, pharmaceuticals, even adhesives. The interest in reducing waste and providing functional coating that can be used right off the coating station is very high. With this increased interest in intermittent coating we also have to consider the technical challenges.Every coating process has a start and stop. In patch coating, this occurs more often than at the beginning and end of a roll. Of course the steady-state continuous flow in between starting and stopping has been discussed at length and has its own issues to deal with. But what special issues are associated with the start and stop of a coating head? For this discussion we will concentrate on slot die patch coating. Any shape can be coated - as long as it is a rectangle!In the start-up and stop flow analysis, the challenge is to reduce waste and defects associated with the transition from fluid flow to not. The considerations of start-up include wetting of the fluid on the substrate, pump control of fluid dynamics, and physical position of the coating equipment to the substrate.