Cross Machine Caliper Profile Control on High Speed Coated Packaging Lines
Cross-machine caliper control demands real-time induction calender profiling to maintain stiffness and prevent high-speed converting line jams.
Dry Coat Density
Coating Characteristic
Mass per unit volume of a finished surface layer determines the physical thickness and opacity provided by the applied chemicals after all moisture has evaporated. The dry coat density quantifies how much solid material, such as calcium carbonate or clay, occupies the space on the surface of the paper. This value is distinct from the wet density of the liquid slurry.
Volumetric Calculation
Formulation ratios between pigments and binders dictate the final compactness of the layer. A high dry coat density suggests a tightly packed structure that may offer superior barrier properties or higher ink holdout for printing. Measuring this property involves calculating the difference between the base sheet weight and the finished coated weight relative to the measured thickness of the coating itself.
Testing laboratories use precision balances and micrometers to establish these figures.
Surface Performance
Porosity of the finished sheet changes according to how the solids settle and dry. When the dry coat density is too low, the coating may appear bulky but lack the structural integrity to withstand the picking forces of tacky inks. Optimization of this parameter ensures that the substrate achieves the desired visual properties without using excessive amounts of raw materials.
This measurement remains a standard metric for mill technicians who manage the cost and performance of coated grades.