Flexographic Anilox Cell Metering Dynamics under High Shear Rate Regimes
Anilox metering under high shear rate regimes depends on ink rheology and blade deflection balance to prevent hydrodynamic lift and coat weight drift.
Water Based Ink Viscosity
Kinetic Resistance
Resistance of aqueous-based pigments and resins to movement determines the volume and quality of ink applied to the substrate. The water based ink viscosity influences the drying speed, colour strength, ink adhesion and the sharpness of the printed image on paper or board. This property is usually measured by the time it takes for a fixed volume of liquid to flow through a standard cup.
Evaporative Stability
Evaporation of water and amines during the printing process causes the fluid to thicken, which can lead to clogged cells and poor transfer. Operators must regularly add water or specialized stabilizers to keep the flow characteristics within the target range. If the viscosity is too low, the ink may soak into the board, causing washed-out colours and blurred edges.
High viscosity can result in heavy deposits that do not dry properly. The temperature of the press room also affects these flow properties. Maintaining a stable environment helps to reduce the frequency of manual adjustments in the ink fountain.
Colour Management
Maintaining a constant flow rate is necessary for colour consistency over long production runs. Automated systems use sensors to monitor the ink in the tank and trigger the addition of fluids as needed. Proper management of the thickness ensures that the press can run at maximum speed without compromising the quality of the packaging.