Bending Force
Resistance to folding indicates the force required to bend a pre-creased paperboard sample by a specified angle. The crease resistance of a board affects how carton blanks behave when they are pushed through high-speed packaging lines. Proper creasing reduces the bending force, ensuring that the carton folds easily along the intended lines rather than bulging or cracking on the face of the board.
Carton Erection
Automated packaging machines rely on consistent resistance values to square up carton blanks efficiently. If the crease resistance is too high, the carton will not open fully or the glued joints might pop open after sealing. When the value is too low, the cartons lack structural integrity and might collapse under the weight of the filled product during shipping and pallet stacking.
Board Thickness
Multi-ply boards require carefully adjusted creasing tools to achieve the right compromise between foldability and stiffness. Thick boards formed of mechanical pulp layers have a high natural stiffness, which demands a deeper creasing groove to disrupt the internal fiber bonds. This localized disruption lowers the torque needed for folding, allowing the carton to maintain its rectangular shape and sit perfectly flat on the retail shelf.
Regular testing using a standard pneumatic bender helps converting plants verify that their creasing dies remain within the specified tolerances throughout a production run.
