Weak Boundary Layer

Converting Impact

Production equipment forces this substrate through rollers and vacuum transfer points where the tension gradients expose any existing separation between layers. High-speed folding cartons experience this stress during the creasing and scoring operation, as the material must withstand sharp deformation without separating at the internal interfaces. Converters measure this resistance through a z-direction tensile test to verify that the internal bond holds under the mechanical strain of the line.

A failure here forces immediate rejection of the entire batch because the board lacks the necessary stiffness to withstand the torque applied by high-speed packing machinery.

Tolerance Management

Mill technicians regulate this property by monitoring the moisture profile and the concentration of chemical binding agents applied during the formation of each wet web. Controlling the drainage rates across the wire sections allows for better fibre interlocking between the incoming plies, which prevents the development of zones with low cohesive strength. Precise calibration of these variables ensures that the bonding energy remains uniform across the entire width of the web, regardless of the variations in stock density or fibre length distribution.

Testing protocols confirm that the adhesive force within the composite structure exceeds the maximum load applied during standard distribution cycles.