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.
Solvent Ink Metering
Fluid Measurement
Precise measurement of ink containing volatile organic compounds ensures consistent colour delivery on non-porous substrates like plastic films or foil-lined board. The solvent ink metering relies on a doctor blade to remove excess fluid from the surface of an engraved roll. This action leaves a known volume in the cells to be transferred to the printing plate.
Viscosity Management
Fast-drying solvents change the viscosity of the ink as they evaporate during the run. To keep the metering consistent, the system must constantly add fresh solvent to maintain the target flow properties. If the ink becomes too thick, the blade will not wipe the roll cleanly, leading to streaks or heavy edges.
Enclosed doctor blade chambers help to contain the vapours and slow down the drying process on the roll. This containment also reduces the amount of solvent lost to the atmosphere. Precise control of the blade angle and pressure ensures that the cell volume remains the only variable in the transfer.
Coating Precision
Uniform distribution of the ink film is necessary for high-speed flexible packaging production. Variations in blade pressure or roll condition can alter the amount of ink delivered, causing colour shifts. Regular maintenance of the wiping edge ensures that the metering remains accurate over long shifts.