Sizing Female Matrix Channels for Uncoated Folding Boxboard Grades
Uncoated folding boxboard requires matrix channel width equal to creasing rule thickness plus 1.8 times caliper to prevent top liner cracking during folding.
DIN 19303
Classification Standard
German industrial protocol establishes a coding system for the identification of paperboard grades based on surface finish and furnish composition. Application of din 19303 allows buyers and mills to communicate specific material requirements using a four-character alphanumeric string. It covers primary categories like virgin fibre and recycled boards along with their coating states.
Code Structure
First letters designate the primary furnish such as G for pigment-coated virgin fibre or U for uncoated recycled material. Secondary characters in din 19303 specify the reverse side color or the specific weight and thickness range. A code like GC1 represents a high-quality virgin fibre board with a white reverse side.
Sourcing Accuracy
Global supply chains rely on these definitions to prevent the accidental substitution of inferior grades during the production of food or pharmaceutical cartons. The standard of din 19303 ensures that the mechanical performance and aesthetic properties of the board remain consistent across different manufacturers. Technical specifications for bending stiffness and brightness are often tethered to these codes.
Compliance provides a clear baseline for quality control audits. Without this shared language, a converter might receive a board that cracks during creasing because the fibre length is insufficient for the intended design. The specification acts as a legal and technical safeguard for the procurement department.