Protective Sleeve
Polyurethane rotary die cutting blankets act as the striking surface for rotary steel rules during high speed corrugated board converting. A replaceable anvil band sits on the cylinder to absorb the impact of the cutting rule and protect the underlying steel drum. These sleeves allow clean penetration of the blades without dulling the steel.
Wear Mechanism
Fibre shearing and creasing require consistent backing resistance to prevent ragged board edges and unseparated waste. As the anvil band experiences repetitive strikes, the polyurethane suffers micro-cuts that gradually self-heal under temperature and pressure. Rotation and lateral shifting of the cylinder disperse the wear patterns.
Uneven wear degrades the cutting pressure, which leads to incomplete cuts.
Operational Lifetime
Downtime and material waste increase when the thickness of the backing becomes irregular. This wear is managed through regular surface grinding of the anvil band to restore a perfectly cylindrical profile. Grinding reduces the outer diameter, which requires a compensatory adjustment of the cylinder drive speed to maintain surface speed synchronisation with the rule cylinder.
Incorrect speed matching causes scuffing, which accelerates blade wear and tears the top liner of the paperboard. When the band thickness falls below the minimum limit specified by the converter, the entire sleeve must be replaced to prevent blade damage.
