Project details

The shrinkage of rubber O-rings usually refers to the size formed in mold design, and the specific calculation method is as follows:

1. Formula for calculating the corresponding dimensions of rubber products and mold cavities: C=(L2 L1)/L1 X 100% C - shrinkage rate of the product rubber material; L1- The size of rubber products measured at room temperature; L2- The size of the mold cavity measured at room temperature.

2. The empirical formula for calculating the shrinkage rate of rubber products based on Shore hardness: C=(2.8-0.02K) X 100% K - Shore hardness of rubber.

3. The general formula for calculating the shrinkage rate of rubber products based on the vulcanization temperature of rubber: C=（ α—β)Δ T · R X 100% α— The linear expansion coefficient of rubber; β— Linear expansion coefficient of mold material, Δ T - difference between vulcanization temperature and measurement temperature, R - volume percentage of raw rubber, sulfur, and organic compound in rubber.

Different rubber materials have different shrinkage rates. Generally speaking, the shrinkage rates of fluororubber, silicone rubber, and EPDM rubber are relatively small, followed by natural rubber and chloroprene rubber, while the shrinkage rates of nitrile rubber are relatively high. In addition, the shrinkage rate of rubber products with different structures may also change. Therefore, when selecting the corresponding rubber material, it is necessary to comprehensively consider its shrinkage rate.

The shrinkage of the rubber O-ring is also related to the design of the mold. When designing the mold, it is necessary to consider the shrinkage rate of the rubber material and determine the size of the mold based on factors such as the structural form of the product. At the same time, when pressing rubber O-rings, it is also necessary to control the process conditions such as temperature and pressure to avoid affecting the quality of the product due to shrinkage.

In summary, in order to achieve the best shrinkage effect of rubber O-rings, it is necessary to comprehensively consider various factors such as materials, mold design, and process conditions.