Mechanical Refining Impact on Multi Ply Boxboard Z Direction Tensile Development
Controlled low energy refining of middle ply mechanical pulp yields superior Z direction tensile development without caliper loss in multi ply boxboard.
Platen Adhesion
Release Force
Substrate retention during flatbed die-cutting depends on platen adhesion, the specific interfacial bond strength established between a paperboard sheet and a carrier blanket under high clamping pressure. Excessive retention tears delicate linerboard during stripping operations, while insufficient holding allows lateral sheet migration and ruins dimensional register on multi-pass embossing runs. Converting plants measure this holding metric in newtons per square meter, evaluating how cleanly a given paper stock releases from the press bed without leaving adhesive residue or suffering fiber pull.
Dynamic Shear
Mechanical stress concentrates along the leading edge of the sheet during the sudden upward stroke of the movable bed. High-speed reciprocating presses demand lower initial tack values to prevent edge delamination, whereas slow-dwell hydraulic units permit heavier coatings that withstand higher peeling loads without premature separation. Laboratory peel testers quantify this behavior by pulling sample coupons at a fixed angle of ninety degrees, recording the peak force required to sever the contact layer at standard room temperature and relative humidity.
Thermal Sensitivity
Ambient shop floor temperatures alter the viscosity of the bonding medium, changing the holding force significantly between morning startups and afternoon production runs. Cooling the chase plate reduces premature tack buildup during long folding carton runs, stabilizing the stripping waste removal process across extended shifts. Presses lacking temperature regulation require frequent adjustments to the blanket formulation to compensate for frictional heat generated during continuous high-tonnage operation.