Calculating Female Cavity Depth and Counter Clearance from Measured Paperboard Bulk
Female cavity depth equal to compressed bulk caliper and counter clearance matching substrate compressed thickness prevent fiber shear during embossing.
Bevel Angle Clearance
Angular Margin
Rotary cutting dies employ a specific relief angle behind the primary cutting edge to prevent the heel of the blade from rubbing against the board during rotation. This angular offset, known as bevel angle clearance, ensures that only the sharp tip of the knife makes contact with the paperboard substrate as the cylinder rotates. Without this void behind the tip, friction increases rapidly.
Wear Response
Repeated contact with abrasive recycled fibers reduces the sharpness of the steel edge over time. As the tip flattens, bevel angle clearance diminishes and the land area of the blade widens, causing the tool to push the material rather than slicing it. This deterioration increases the pressure required to complete the cut, leading to dust generation and rough carton edges.
Board Deflection
Symmetrical blades require higher penetration forces than asymmetrical counterparts because they must displace equal amounts of material on both sides of the cut. Proper bevel angle clearance allows the displaced board fibers to compress and slide past the knife during the penetration phase of the die cutting cycle. This displacement behavior determines the cleanliness of the finished carton blank, since insufficient relief causes the board to compress rather than shear.
The resulting compression fractures the clay coating along the score lines and ruins the print finish.