Structural Deformation
Controlled shear deformation creates localized internal delamination along folding lines without rupturing outer linerboard surfaces. Converting technicians evaluate paperboard creasing mechanics to ensure clean ninety-degree folds on folding boxboard and solid bleached board cartons. The physical mechanics govern female groove width and male rule penetration depth parameters during die-cutting.
The analysis boundary excludes uncreased sheet bending and rigid box corner stay tape applications.
Shear Rupture
A steel creasing rule forces the paperboard substrate into a defined female channel matrix under high compressive load. The mechanical displacement creates internal shear stress between individual fiber plies, forcing the middle plies to delaminate locally. Internal delamination creates an internal hinge mechanism that allows the outer liner to stretch smoothly while inner plies compress without surface cracking.
Inadequate crease depth leads to high folding resistance, surface cracking and panel bulging on automatic packing lines. Analyzing paperboard creasing mechanics enables box makers to adjust die-cutter settings for varying board calipers and humidity conditions.
Carton Conversion
Proper crease formation ensures predictable bending resistance and square carton geometry on high-speed filling lines. Defective creases cause panel bulging and packaging machine jams during folding operations. Board ply bond strength determines the shear stress threshold needed for clean crease development.
