Thermoset elastomer
Nitrile rubber (NBR)
Compression moulded and trimmed by hand or by die. Flash is not recoverable once cured, so every trim is yield lost for good.
Typical scrap rate
3.5%
Yield multiplier
1.0363x
Effect at 1,000 units
At 1,000 units it adds $0.16 to a $14.11 landed unit. The trim loss is permanent: a thermoset cannot be reground and run again.
Notes
A thermoset cannot be reground. Once the rubber has cured it will not flow again, so flash, trim and any part rejected after cure is gone as material and as the press time that made it.
This is why elastomer suppliers push hard on cavity count and on tolerance. Every extra cavity spreads the same press cycle over more good parts, and every tightened tolerance moves parts from the good pile to the 3.5%.