What are the reasons for difficult exhaust and cracking of silicone products due to shrinkage?

Why is it difficult for silicone products to exhaust and cause edge shrinkage and cracking? The phenomenon of cracking, pulling, and shrinking at the edge (edge skin) of silicone products is referred to as "edge burning" by industry insiders. According to the years of production experience of Dongguan rubber and plastic manufacturers, there are four main reasons for the widespread burning of edges:

1. Excessive content of vulcanizing agent in the rubber material (i.e. excessive amount of vulcanizing agent added);

2. Excessive vulcanization time;

3. The vulcanization temperature is too high;

4. The vulcanization pressure of the vulcanizing machine is too high.

There are four reasons why silicone products have difficulty venting:

1. If the exhaust distance is too large or too short, it should be strictly controlled between 1-5cm;

2. If the first exhaust is not discharged, a second exhaust can be carried out;

3. Not reaching the vulcanization time;

4. Rubber has problems with moisture, uneven dispersion of vulcanizing agents, and uneven mixing of rubber.

In addition, the difficulty of exhaust and edge shrinkage cracking of silicone products usually occur at the parting of the mold. To solve these problems, attention should also be paid to other details:

1. Pay attention to the quantity of materials;

2. At the same time, check whether the clamping edge of the mold is damaged. If necessary, polish with an oilstone;

3. Is there any scratch during demolding, and is the R angle reversed at the scratch location;

4. Whether to use inferior silicone also has a certain relationship.

In short, different silicone products will have different problems. The experiment can be adjusted according to its own requirements, process, temperature, vulcanization time, and pressure.