Rubber grommets vulcanization common quality problems

The quality of Rubber grommets is related to the nature of the compound itself, the composition of the formulation, the manufacturing process, the structure and operation of the molding die, and the state of the vulcanization equipment.

Product quality problems, causes and countermeasures are listed in the table below. These quality problems are also the cause of non-conforming products.

Quality issues Cause Countermeasures
Rubber Grrommets are oversized (expressed in Grrommets thickness unevenness, poor shape, and dimensional requirements)1. Poor parallelism of equipment and mold

2. Rubber shrinkage calculation is not allowed

3. The mold is not processed properly, and the research is not suitable.
1. When the mold is required to be processed, it is necessary to ensure the degree of parallelism.

2. When designing, be sure to broadcast the shrinkage rate of the rubber compound.

3. Improve mold processing accuracy
Product surface is notched1. Insufficient amount of glue

2. Pre-formed semi-finished products are small in size or less in glue

3. The fluidity of the rubber is too bad

4. Under pressure

5. The device has a pressure drop phenomenon

6. The filling method is incorrect.

7. The mold temperature is too high

8. The mold feed port is too small

9. Skeleton shape large wall thickness

10. The gap between the skeleton and the cavity is too small, and the rubber flow path is not smooth.

11. Clamping rate is too fast

12. Improper mold design, excessive amount of lost glue or mold can not seal the glue, the rubber material runs from one side, and the other side lacks glue

13. The mold is not well vented and the gas occupies the glue level.
1. Ensure that the molding compound is accurate

2. The size and weight of the semi-finished products should be adjusted accurately.

3. Adjust the formula or process (such as rubber preheating) to improve liquidity

4. Improve equipment pressure

5. Repair equipment to achieve pressure holding performance •

6. Change the operation process

7. Adjust the mold temperature, ie the hot plate temperature of the vulcanizer

& increase the mold feed port

9. Preheat the large-walled skeleton before entering the mold.

10. Improve the product design structure, the rubber layer should not be too thin, or punch, drill or slot the skeleton to ensure the rubber flow channel

11. Slow down the mold clamping rate, loosen several times

12. Modify the mold again; there must be a vent hole and a glue tank when designing the mold
Cavity misalignment
1. Mold manufacturing accuracy is not high

2·Mold positioning system failure

3. Mold misalignment

4. 45° type apron flash thickening
1. Improve mold processing accuracy and assembly technology level

2. Repair positioning system

3. Accurate positioning

4. Design the glue tank to avoid thickening of the flash