Counter-Die Recess
The polymer or fiber board strip applied to the cutting plate contains a precisely sized groove that receives the paperboard during the creasing stroke. The width and depth of each matrix channel are matched to the thickness of the board to ensure a uniform fold.
Creasing Profile Formation
Mechanical pressure drives the paperboard into the open groove, causing the fibers to bend and separate along the pre-defined line. A matrix channel must be clean and free of paper dust to maintain the consistency of the folding bead throughout the production run. If the groove is too narrow, the board will be pinched too tightly, which often causes the surface coating to crack.
If the groove is too wide, the bead will be shallow and poorly defined, resulting in a loose fold and crooked boxes.
Material Selection Choice
Converters choose between paper-based and plastic matrices depending on the run length and the required accuracy. Plastic matrices offer higher wear resistance, retaining their groove shape and dimension over hundreds of thousands of impressions. Self-adhesive backing allows for rapid setup and alignment on the steel cutting plate, minimizing downtime during job changes.
Monitoring the depth of the groove ensures that the crease stiffness does not rise, which could cause automated cartooning lines to jam.
