Optimizing Creasing Rule Geometry for Coated Paperboard Packaging
Optimizing creasing rule tip radius and channel geometry enables controlled internal board delamination, eliminating coating cracking and springback jams.
Rule Height Clearance
Tooling Geometry
Die-cutting and creasing of folding cartons require precise mechanical adjustments to the heights of the steel rules relative to the plate. This spacing, known as rule height clearance, represents the difference in height between the cutting rules and the shorter creasing rules. This clearance is necessary to ensure that the board is cut through while the crease is only compressed and not ruptured.
Adjustment Process
In a typical die-cutting tool, the cutting rule is higher than the creasing rule by an amount that corresponds to the thickness of the board and the counterplate. If the rule height clearance is too small, the creasing rule will press too hard, causing the surface of the board to crack. If the clearance is too large, the crease will be too shallow, resulting in high folding resistance and misaligned panels.
Operators adjust this clearance using thin shims or by selecting different height rules in the laser-cut wooden die board.
Production Influence
Consistent clearance across the entire sheet prevents local failures where some cartons are hard to fold. This adjustment is critical when switching from thin paperboard to thick corrugated grades. Correct clearance reduces wear on both the rules and the counterplate.