Groove Geometry
Vertical groove dimensions in creasing matrix channels establish the space available for paperboard displacement during die-cutting scoring operations. The metric matrix depth defines the vertical distance from the top surface of the channel strip down to the backing carrier tape. Correct depth permits full board deformation without bottoming out or crushing the crease bead.
The dimensional standard applies to channel matrix strips and counter plates mounted on cutting platens.
Mechanical Forming
Rule thickness and board caliper determine the appropriate channel depth according to converting selection tables. Insufficient matrix depth restricts board movement, causing creasing rules to shear through the top liner or fracture internal fibers. Excessive depth prevents rules from forcing board plies deep enough into the channel, producing shallow scores with high bending resistance.
Die cutters select matrix depths equal to board caliper for solid bleached boards, or slightly less for compressible recycled grades. Phenolic counter plates milled to exact depths offer superior durability during long production runs compared to pressboard strips. Matrix positioning must remain perfectly centered over creasing rules to prevent asymmetrical score formation.
Score Quality
Worn matrix channels lose depth over extended runs as channel floors compress. Verifying matrix depth maintains uniform crease height across large platen press layouts.
