After vulcanization, there are always some bubbles on the surface of the sample, which are of different sizes. After cutting, there are also a few bubbles in the sample.
Cause analysis of air bubbles on rubber surface
1. Rubber mixing is not uniform and operators are not standard.
2. The parking of rubber film is not standard and the environment is unsanitary.
Management is not standard.
3. The material is moist (add some calcium oxide when mixing)
4. Insufficient vulcanization and unripe appearance of bubbles.
5. Insufficient curing pressure.
6. There are many impurities in the vulcanizing agent, and the impurities of small molecules will be decomposed in advance
7. The exhaust design of the mold itself is not reasonable, and the gas cannot be discharged in time when the rubber punch line is drawn!
8. Products are too thick, with too little glue, and slow heat transfer of rubber. After vulcanization, rubber fluidity decreases, resulting in lack of materials, so bubbles may occur.
9. Exhaust is not discharged during vulcanization.
10. Formulation, curing system should be improved.
Solution: improve the curing pressure and time
1. Extend the curing time or increase the curing speed.
2. Thin pass several times before curing.
3. Vent more times during curing