Die Resistance
Folding carton substrates require an engineered balance of stiffness and residual elongation to form clean ninety degree angles without surface cracking along the hinge line. Creasing performance determines whether paperboard maintains structural integrity during high speed mechanical conversion on rotary press lines. Multi layer boards demand specific depth ratios within the channel matrix to prevent internal delamination during compression.
Press operators adjust counter plate thicknesses when lower density recycled content exhibits variable surface tension under high humidity shop floor conditions.
Surface Stress
Outer liner components experience maximum tensile elongation across the convex radius of a fold while interior plies undergo high compression forces simultaneously. Creasing performance governs how effectively surface coatings distribute these mechanical loads without fracturing the clay layer or exposing raw cellulose beneath the print face. Board mills apply specific starch sizing formulations to enhance internal bond strength and resist shear stress generated during rapid matrix deformation.
Carton converters measure angular springback rates after compression to verify that finished blanks retain dimensional accuracy before adhesive application on high speed folding lines.
Matrix Tolerance
Channel width and depth specifications dictate the operational window for reliable joint formation during automated packaging assembly sequences. Creasing performance establishes the precise limits of tolerance between rule thickness and groove geometry across varying caliper ranges. Excessive clearance leads to rounded hinge formation and structural failure under load, whereas tight tooling configurations cause immediate board rupture and box line stoppages.
Laboratory testing protocols quantify this resistance by measuring the force required to fold a pre scored sample through ninety degrees over a defined dwell time.
