Polyurethane Soft Touch Film Selection for Folding Cartons
Polyurethane soft-touch films provide superior scratch resistance and score fold integrity compared to BOPP but require higher temperature control and lower web yields.
Cartonboard Scoring Rule
Creasing Geometry
Metal tooling components define the profile of a fold in packaging materials. Use of a cartonboard scoring rule allows for the controlled displacement of internal fibres within the board structure during the die-cutting process. It consists of a steel strip with a rounded tip that creates a permanent deformation without rupturing the surface liner.
Conversion Tolerance
Width and height specifications determine the success of high-speed folding operations. If the rule height is too low, the crease lacks definition, leading to erratic folding torque. Selecting the correct rule thickness ensures the substrate delaminates internally to form a functional hinge.
Fibre Management
Different board calipers require specific combinations of rule width and channel depth. Solid bleached sulfate requires a different approach than recycled board due to variations in tensile strength and moisture content. Precise alignment with the underlying matrix or counter-crease is required to prevent cracking on the outer bend.
The relationship between the rule width and the channel width determines the strain applied to the surface coating. Using a rule that is too narrow for a thick board leads to a burst crease because the elongation capacity of the top liner is exceeded. This mechanical interface governs the final appearance of the finished box.