Ultrasonic Wave Attenuation Basics for Paperboard Creasing Quality
Non-destructive ultrasonic wave attenuation evaluates paperboard crease quality by measuring acoustic energy loss caused by internal shear delamination.
Score Bend Resistance
Mechanical Property
Packaging blank runnability on automated carton erecting and packing machinery depends on the controlled mechanical force required to fold a pre-creased paperboard hinge through a specified angle. In converted packaging evaluation, score bend resistance measures the peak force or bending moment necessary to fold a scored carton panel across a ninety-degree angle compared to the force required to bend an uncreased board sample. The metric determines how cleanly carton blanks open and fold on high-speed filling lines without skewing, panel bowing, or mechanical jamming.
Crease Evaluation
Laboratory testing utilizes specialized score bend testers where a pneumatic clamp anchors the carton body while a motorized push rod deflects the pre-scored flap through a precise ninety-degree arc over a standard cycle time. Maintaining an optimal score bend resistance requires achieving a score ratio, calculated by dividing the scored bending force by the unscored board stiffness, typically between thirty and fifty percent. Ratios exceeding this threshold indicate insufficient creasing, leading to carton spring-back and opening failures on packaging machines.
Ratios falling below thirty percent signal excessive internal fibre rupture, resulting in floppy panels, crooked folds, and loss of structural box compression strength.
Line Performance
Packaging lines operating at speeds exceeding four hundred cartons per minute require tightly controlled bending resistance across all score lines. Symmetrical creasing ensures square carton erection, reliable adhesive tab bonding, and seamless insertion of inner contents, preventing costly line stoppages during commercial packaging runs.