Creasing Rule Selection for Coated Folding Boxboard Conversion
Selecting steel creasing rules and matrix channels for coated FBB requires matching board caliper and CTMP core shear limits to prevent surface cracking.
Grammage Basis
Mass Distribution
Fibre density determines the weight of a square metre of substrate within a manufacturing environment. Grammage basis provides the metric for quantifying this distribution across different production runs of paper or board. It serves as the primary gauge for determining how much raw pulp is required for a specific unit area of the finished sheet.
The calculation involves dividing the total mass by the area of the sample while ensuring standard atmospheric conditions apply to the weighing process.
Production Tolerance
Converters adjust the setting of the headbox or the spray of the wire to manage this value during the wet end stage of papermaking. Fine paper grades carry lower tolerances for variation than coarse packaging materials where regional standards dictate the acceptable range of deviation. High grammage basis values indicate a thicker or more compact sheet construction that resists deformation under mechanical pressure.
Variations across the web width affect the physical properties of the final product and dictate how the material behaves on a high speed printing press or a filling line.
Performance Constraint
Operational limits in a converting facility rely on these values to ensure machine compatibility. Printing plates and folding equipment demand consistency because fluctuations in the substrate weight force constant mechanical recalibration to avoid sheet breaks or registration errors. Rigid packaging structures require a specific value to maintain the integrity of a box during compression testing.
Consistent grammage basis values guarantee that each sheet of material carries the exact structural load required by its technical specification.