Waterborne Barrier Dispersion Application Parameters on Folding Boxboard
Waterborne dispersion application on folding boxboard requires precise coat weight control, shear-matched viscosity, and staged drying to prevent pinholing.
Scoring Rule Width
Tooling Dimension
A tooling dimension for the thickness of the steel blade used in die-cutting determines the geometry of the resulting fold line. Scoring rule width must be precisely matched to the thickness of the substrate and the width of the female die channel to prevent cracking. This measurement is typically expressed in points, where one point equals approximately zero point three five millimeters.
Mechanical Interaction
The rule pushes the board into the groove, stretching the outer fibres and compressing the inner ones to create a permanent hinge. Selecting the correct scoring rule width ensures that the displacement of the material is sufficient to allow for a clean fold without causing a total rupture. If the rule is too thin, the score will be weak and the board will not fold accurately on the automated packing line.
A rule that is too thick will exert excessive pressure and likely damage the top liner.
Converting Tolerance
Precision in the die-making process is required to maintain the relationship between the rule and the crease channel. This scoring rule width is a fixed value for a specific job, but it may be adjusted when switching between different board grades or densities. Variations in the moisture of the board can change how it reacts to the rule, sometimes requiring a change in the tooling setup.