Paperboard Creasing

Material Resistance

Fiber orientation within the sheet dictates how the substrate reacts to localized pressure. Dense recycled boards often require deeper channels than virgin fiber stocks because the lignin content behaves differently under high impact force. A machine operator selects the channel width based on the caliper of the sheet to ensure the fibers undergo enough stress to yield but not enough to sever.

The geometry of the groove directly impacts the breakout force required for a machine to initiate the fold. Higher moisture content in the paperboard increases the plastic flow of fibers during this operation. Operators monitor the resulting score profile to verify that the bead sits squarely in the channel without tearing the surface liner.

Production Integrity

Automated lines depend on accurate folding to achieve tight clearances at the point of adhesive application. If the crease remains too shallow, the box resists the closing movement and places excess force on the flap geometry during the sealing cycle. Variations in the moisture levels of the environment shift the tolerance windows for consistent folding.

Each batch of packaging requires testing of the fold force against the specified machine settings to avoid line downtime. A consistent score profile guarantees that the final pack maintains its intended shape throughout distribution and logistics.