How to choose the correct o-ring size?

The correct selection of o-ring specifications is mainly related to material, size, tolerance, and compression. The following is the experience of ZHEJIANG JIACHENG NEW MATERIAL CO., LTD. for you to share:

 
1. When choosing the specifications of the o-ring, the material of the o-ring must be determined first. At present, the materials of the o-ring in industrial parts and life include NBR nitrile rubber, NR natural rubber, CR neoprene rubber, EPDM EPDM Rubber, HNBR hydrogenated nitrile rubber, SILICOME silicone, FKM, VITON, fluorine rubber, FLS silicone fluorine rubber, PU polyurethane, SBR styrene butadiene rubber, Buna rubber, acrylic rubber ACM, PTFE, PTFE and so on. Each of the above materials has its own destination and purpose, such as oil resistance, chemical resistance, high and low temperature resistance, wear resistance and so on. Therefore, when choosing the o-ring specification, you must know where the product is used, what it needs to withstand, what it does, and its service life, so that you can choose the o-ring material you need.
 
2. The size of the o-ring is expressed in terms of outer diameter, inner diameter and wire diameter. As long as the dimensions of the inner diameter and the wire diameter are indicated on our engineering drawings, the outer diameter is equal to the inner diameter+2*wire diameter. Or just mark the dimensions of the outer diameter and the wire diameter. You can choose one of the two.
 
3. O-ring specification tolerance mainly includes inner diameter tolerance and wire diameter tolerance. The o-ring specification tolerance mainly depends on the size of the size, the larger the size, the larger the tolerance of course. For example, the tolerance standard of O-ring with inner diameter of 0.05 to 1.79mm is +/-0.10MM, and the tolerance of O-ring with wire diameter of 0.05 to 1.79MM is +/-0.07MM.
 
4. The amount of compression is very important when choosing the specification of the o-ring. Because the selection is incorrect, it will not be sealed when the product is assembled, or it will be too tight when assembling, which will not play the required role of the product. Then how do we correctly choose the compression amount of the o-ring specification, the following is a reference for you: the compression amount of the o-ring is generally mainly determined by the hardness and material of the o-ring, if the hardness of the o-ring is 70 degrees, Then the compression of the o-ring is equal to 20%. Of course, the lower the hardness of the o-ring, the greater the compression of the o-ring, which is mainly used in places with low pressure. Then the higher the hardness of the o-ring, the smaller the compression of the o-ring, which is mainly used in environments with high pressure, pressure resistance and low resistance. And so on to get the compression of any durometer o-ring you need.