The Stripe Issue Caused by Tension Fluctuations in Roll-to-Roll Laboratory Coaters and Its Solutions

This article analyzes the causes of coating stripes caused by tension fluctuations in roll-to-roll laboratory coaters and proposes corresponding countermeasures. Tension variations cause substrate expansion and contraction, resulting in bright and dark stripes, with their spacing correlated to the fluctuation cycle of mechanical components. Key parameters include coating speed, liquid viscosity, and oven temperature. Solutions involve optimizing the mechanical system, such as adding inertia compensation rollers and using dual closed-loop control, and adjusting the process, such as improving liquid leveling properties and oven temperature. Detection methods include online thickness measurement and spectrum analysis. Actual cases show that replacing encoders or using fresh liquid can effectively reduce stripes.