Cause Analysis:

1. Molding temperature is too high or the temperatures of the upper and lower molds are inconsistent.

2. Venting is too open or venting time is too late.

3. Rubber compound cures too quickly.

4. Mold structure is unreasonable and lacks overflow channels.

5. Excessive material weight.

Improvement Measures:

1. Adjust molding and vulcanization temperatures, and synchronize the temperatures of the upper and lower plates.

2. Adjust venting distance and venting time.

3. Strictly follow the mixing process standards or adjust the formulation and mixing process to avoid using rubber that has been stored too long (quick-cure).

4. Add overflow channels at flashing positions.

5. Control the weight of individual rubber portions.