Dynamic Crease Stiffness Reduction Ratios under Ultra High Speed Packaging Line Strain Rates
Dynamic crease stiffness reduction ratios must be evaluated under operational strain rates of 1000°/s to 5000°/s to prevent high-speed cartoning line jams.
Crease Reduction Ratio
Stiffness Evaluation
Measurement of the force required to bend a creased board compared to an uncreased board defines the efficiency of the scoring process. This ratio of forces is the crease reduction ratio, which indicates how easily a carton will fold on high-speed packaging lines. A low ratio indicates that the crease has successfully broken the internal fibre structure to allow effortless bending.
Die Adjustment
The depth of the creasing rule and the width of the matrix groove must be balanced to achieve the target folding performance. If the score is too shallow, the force required to bend the carton remains high, leading to distorted panels or glue-line failures. Adjusting the penetration depth of the rule into the paperboard optimizes the score without tearing the linerboard face, ensuring a clean fold along the intended axis during packaging assembly.
A highly compressed groove decreases the force needed for folding by splitting the internal plies of the board, which protects the outer printed surface from unsightly cracking.
Performance Metric
Accurate measurement of bending resistance is obtained using standardized electronic torque testers. This measurement is critical for carton designs that run on automated filling machines where high resistance can jam the feed mechanism. Proper evaluation ensures that the carton remains structural while folding with minimal resistance.