Dispersion Barrier Coating Mechanics under Crease Stresses in Flexo Converting
Flexographic dispersion barrier coatings retain water and grease resistance under crease stresses only when coating elongation capacity matches board strain.
Score Channel Width
Tooling Parameter
The distance between the shoulders of a creasing matrix determines the shape of the permanent fold line in paperboard. This dimension is called the score channel width and must be calibrated to match both the board thickness and the creasing rule. Incorrect settings lead to either ruptured board fibres or messy, off-center folds during high-speed carton assembly.
Mechanical Calibration
Proper crease formation requires the board to be pressed into the channel to create a clean bulbous hinge. The score channel width must be wider than the creasing rule plus twice the board thickness to allow the material to draw in without tearing. If this clearance is too narrow, the excessive shear stress cuts through the outer liner of the paperboard.
When it is too wide, the crease is weak and the carton corners will not form a neat ninety-degree angle on the filling line.
Production Outcome
Maintaining the correct dimensional ratio prevents the outer surface from cracking when the board is folded through its full range of motion. It also reduces the force needed to fold the carton flaps, which is critical for high-speed automated packaging machinery. Stable creasing prevents jammed feeders and ensures consistent package geometry across the entire run.