Steel Specification
The dimensional width of a steel blade used to indent paperboard during the die-cutting process dictates the width of the resulting fold line. Selecting the correct creasing rule thickness prevents the outer liner of the board from cracking and ensures a clean, square fold. This parameter is typically chosen in relation to the thickness of the cartonboard being processed.
If the blade is too narrow, the board fibres do not compress properly, whereas an overly thick blade ruptures the surface. Mill operators and converter technicians consult standard selection charts to choose the appropriate point size for the rule based on the caliper of the substrate.
Geometry Ratio
Mechanical clearance in the creasing channel must accommodate both the compressing rule and the displaced board fibres. The relationship between the creasing rule thickness and the groove width of the counter-die determines the quality of the crease. In standard folding carton production, the groove width equals the rule thickness plus twice the board thickness.
This ratio ensures that the board is folded without shearing the cellulose matrix.
Material Tolerance
Structural integrity of the final package depends on this precise alignment. When the creasing rule thickness is matched to the board grade, it minimizes the force required to fold the carton on automated filling lines. Excessive folding resistance can cause the carton to warp or jam the packaging machinery.
Correct creasing dimensions ensure that the cartons remain erect and run efficiently through high-speed gluing and cartoning processes.
