How to Choose the Specification of O-ring Correctly

  Common problem    |      2016.07.04    |     Hit:412    

Correct selection of O-ring specifications is directly related to material, size, tolerance and compression. Here is my experience for you to share:

1. When choosing the specifications of O-rings, we should first determine the material of O-rings. At present, the materials of O-rings in industrial parts and life include NBR nitrile rubber, NR natural rubber, CR chloroprene rubber, EPDM EPDM EPDM, HNBR hydrogenated nitrile rubber, SILICOME silicone rubber, FKM, VITON, fluorine rubber, FLS silicone fluorine rubber, PU, SBR butadiene. Styrene rubber, Buna Buna rubber, acrylate rubber ACM, PTFE, PTFE, etc. The above materials have their own destinations and uses, including oil resistance, chemical resistance, high and low temperature resistance, wear resistance and so on. So when choosing O-ring specifications, we must know where the product is used, what it needs to endure, what role it plays, and its service life. Only in this way can we choose the O-ring materials you need.

2. O-ring specifications are expressed by outer diameter, inner diameter and line diameter. In our engineering drawings, as long as the dimensions of inner diameter and line diameter are indicated, the outer diameter is equal to the inner diameter + 2* line diameter. Or just mark the size of outer diameter and line diameter. Either way.

3. The specifications tolerance of O-ring mainly includes the tolerance of inner diameter and line diameter. O-ring specification tolerance mainly depends on the size of the size, the larger the size, of course, the greater the tolerance. If the inner diameter of O-ring is 0.05 to 1.79mm, the tolerance standard of O-ring is +/-0.10MM, and that of O-ring is +/-0.07MM with the inner diameter of 0.05 to 1.79 MM.

4. When choosing O-ring specifications, the compression is very important, because the selection is incorrect, otherwise the product will not be sealed, or the assembly will be too tight, so it will not play the role required by the product. Then how do we choose the compression of O-ring specifications correctly? Here's a reference for you: The compression of O-ring is generally mainly determined by the hardness and material of O-ring. If the hardness of O-ring is 70 degrees, then the compression of O-ring is equal to 20%. Of course, the lower the hardness of O-rings, the greater the compression of O-rings, mainly for low-pressure places. The higher the hardness of O-ring, the smaller the compression of O-ring. It is mainly used in high pressure, pressure resistance and low resistance environment. By analogy, you can get the compression of any hardness O-ring you need.