Tooling Geometry
Steel profile strips embedded within die-cutting platens press rounded impression ridges into paperboard sheets to facilitate precise folding. A scoring rule features a rounded working edge designed to deform paper fibers locally without fracturing board surfaces. Rule heights are calibrated relative to adjacent cutting rules, with standard thicknesses measured in point sizes such as two-point or three-point rule.
Correct rule geometry forms an accurate hinge line that guides folding carton converting operations.
Deform Mechanics
Press force drives the rounded edge into paperboard, pushing board layers down into an underlying counter-matrix channel. This mechanical impression ruptures internal interply bonds while leaving outer linerboards intact. Controlled internal delamination allows the board to fold cleanly along the score line with minimal bending resistance.
Board Tolerance
Incorrect rule height selection leads to liner cracking or shallow creases that resist automated folder-gluer operations. Excess rule height pierces the top liner during impact, reducing box edge strength and causing ink flaking along creases. Insufficient rule height produces incomplete delamination within core plies, resulting in crooked score lines and poor carton squareness.
Variations in paperboard caliper require precise adjustments to matrix channel width and rule thickness across production lots. Machine speed variations alter impact force, necessitating mechanical compensation on flatbed and rotary die-cutting systems. Wear on scoring rule edges gradually changes crease profile, requiring scheduled re-tooling to maintain consistent folding performance.
