Abstract
Stripe coating of narrow width was investigated experimentally. Dilute Newtonian solutions were used on test fluids. The coating width varied between 10mm to 1mm. A flow visualization technique was applied to observe the onset of flow instability. If the coating width is above 10mm, ribbing would appear as the coating defect at high speed for low-viscosity solutions. However, if the coating width is between 2~5mm, the uniform coated surface will break into a few rivulets and then break into short line periodically at even higher speed. The maximum stable coating speed was also examined. It was found that several parameters, such as fluids viscosity、coating gap and surface tension, will influence the maximum coating speed.