This technical decision belongs to cutting die repair and refurbishment service scope. Ejection rubber does more than push a cut part out of the die. It controls how the material approaches the rule and how it releases after the cut. When rubber tires, the symptom is often mistaken for blunt cutting rule.
Permanent compression and hardening
If rubber does not return to its original height after pressure is removed, ejection force has fallen. A hardened surface can mark board, while a soft or missing zone allows the part to stay on the rule. Comparing zones on the same die makes imbalance visible.
Parts remaining in the die
Check rubbering when parts stick at certain corners, operators must pull them free or waste collects between rules. Simply adding harder rubber is not a complete fix; placement and clearance around the cutting rule matter.
Marks and waviness around the cut
Rubber that is too high or too close to the rule can mark thin board. Uneven rubber can produce waviness over broad panels or unwanted pressure near a crease. Replacement should account for the current material and press condition.
Localized replacement or a complete reset?
One torn corner may justify a localized replacement. If most rubber has aged, hardness varies or previous patches are inconsistent, rebuilding the full rubber pattern provides a more predictable result.
Application note
Photograph the rubber surface and the retained cut part so rule wear can be separated from a rubbering problem.
- Use the current material and dimensions.
- Compare a clean sample with the defective sample.
- Record the decision with photographs and drawings.
