Causes of bubbles:

1, rubber mixing is not uniform, the operator is not standard. In accordance with the reasonable feeding sequence and the number of thin pass as well as the back pressure process after parking and curing.
2, rubber film parking is not standardized, the environment is not sanitary. Management is not standard. A foreign substance.
3, the material is moisture (add calcium oxide when mixing)
4. Insufficient vulcanization and immature looks like bubbles.
5, the vulcanization pressure is insufficient.
6, curing agent more impurities, small molecule impurities into early decomposition, bubble residual products
7. The exhaust design of the mold itself is unreasonable, and the gas can not be discharged in time when the rubber material is punching the line.
8, the product is too thick, glue material is too little, rubber heat transfer is slow, the appearance of vulcanization, rubber liquidity decline, resulting in lack of material, so it may produce bubbles. Adjust the vulcanization rate, not too fast.
9. The exhaust is not arranged well in the vulcanization process. Improve exhaust frequency and exhaust time interval.
10, formula problem, curing system to improve. It is recommended to choose low temperature and slow speed (relative).

Solution: to improve the vulcanization pressure and time

A, prolong the curing time or improve the curing speed. Reasonable range of curing temperature.
B, a few times before vulcanization. Place to mature and then pressure back
C, vulcanization when the number of exhaust a little more. Exhaust time interval reasonable arrangement.
D, reduce the Mooney of the mixed glue, choose the rubber material with small air tightness (raw glue or formula to reduce air tightness).

Poor rubber-metal bonding will cause a large amount of residual gas at the bonding site, which will shrink when pressurized. Once the pressure is removed and the gas diffuses, bubbles will appear between the rubber and the metal where the rubber layer is thinner and the area is larger.