Folding Boxboard Internal Ply Shear Stiffness Standards during Die Cutting
Core shear stiffness governs folding boxboard creasing performance; correct values enable middle ply delamination while preventing outer coated liner failure.
Die Cutting Mechanics
Force Application
Pneumatic and hydraulic actuators govern die cutting mechanics by translating rotary motor output into linear downforce across steel rule platens. Press loads reach two hundred tons on heavy cartonboard grades while maintaining parallelism within five microns across the bed. Rotary cylinders require precise face contact to prevent plate deflection during high speed folding carton production.
Toggle linkages multiply torque at bottom dead centre to shear through dense laminated substrates without crushing internal flutes.
Edge Deformation
Shear angle geometry dictates how die cutting mechanics fractures fibre networks during board separation. Beveled steel rules exert lateral compression alongside vertical penetration, which induces internal delamination if clearance tolerances drift outside standard limits. Proper counterplate hardness prevents premature burr formation on coated folding boxboard liners.
Thermal expansion alters tool dimensions during long press runs, changing fracture propagation angles and creating rough edges on corrugated outer facings.
Waste Stripping
Pin and air blast arrays remove internal cutouts through synchronized timing built into die cutting mechanics. Vacuum manifold pressure draws scrap matrices away from finished blanks before delivery stacking occurs. Stripping boards rely on ejected urethane rubber pads to force complex window cutouts clear of the moving web.
Sheet tension must remain constant throughout matrix separation to avoid misregistration on high register print work.