Calculating Female Cavity Depth and Counter Clearance from Measured Paperboard Bulk
Female cavity depth equal to compressed bulk caliper and counter clearance matching substrate compressed thickness prevent fiber shear during embossing.
Compression Ratio
Volume Reduction
Measurement of thickness change in a fibrous sheet under a defined compressive load provides the basis for characterizing material density variations during manufacture. The compression ratio represents this proportional reduction in caliper as the sheet passes between pressurized rolls or creasing dies. It determines how much the porous network of the board consolidates during converting.
A high ratio yields a smoother surface finish but can reduce the bending stiffness of the material.
Fibre Consolidation
Fibre behavior under pressure is dictated by the moisture content and the refinement level of the pulp. In calender runs, a targeted compression ratio is maintained to optimize printability while preserving the internal bond strength of the board. If the pressure exceeds the structural resistance of the fibres, permanent cell wall damage occurs, which degrades the mechanical performance of the finished carton.
Operating within correct parameters prevents the sheet from becoming brittle. Too much force collapses the void space inside the sheet, which permanently reduces the cushioning capacity of protective corrugated packaging.
Crease Tolerance
Die clearances in creasing operations must accommodate the natural volume reduction of the board without inducing structural fractures. Inadequate compression fails to form a well-defined crease, leading to irregular folds on filling lines.