O-rings or packing joints are specially designed rubber seals to manage the path of gases or liquids by compressing surfaces. Many machines have these seals because they are reliable and cost-effective. You may use them for both dynamic and static applications. However, it is important to determine the appropriate O-ring dimensions to prevent malfunctioning issues and leaks in your machine. So, find a brief guide to choosing your O-ring sizes for your applications below.
Detecting the perfect O-ring size
The accurate cord thickness and inner diameter vary with the application.
Inner diameter:
- Axial seal – The O-ring is positioned against the groove’s outer or inner diameter.
- Radial seal – You may need to stretch around the O-ring in your piston.
Cord thickness:
There will be around 25% compression in case of static application. If the compression crosses its limit, the O-ring receives an additional stress. It also results in premature damage to the component.
However, the compression will be around 16% for the dynamic application.
There are some internationally acceptable O-ring size standards.
- AS 568 – The most popular size for your O-rings.
- DIN 3771– It has no additional code per size.
- ISO 3601-3 – Deal with surface quality and tolerance.
How to find the best size for your O-rings
The most important factors that you must not overlook are:
Size – With a standard-sized O-ring, you will save money and time on custom tooling. Some applications also need a custom O-ring.
Temperature – As most industries have become highly advanced, professionals have invested in new equipment. So, you will find a variation in the operating temperatures. Today, O-rings are designed to endure wide temperature ranges. Compound elastomers in O-rings are intended to work across various temperature levels. O-ring is essential to operate the machinery and ensure you have chosen the right elastomer.
Application – This is another relevant factor while determining the elastomer type and dimensions. O-rings have potential dynamic and static settings. You have to learn about the accurate groove dimensions and manufacturing tolerances to add O-ring to the design.
Permeability – Gases may permeate through the O-ring, but it depends on the material hardness and type. Lack of lubrication also causes this issue. Higher durometer compounds have comparatively low diffusion rates. Moreover, if the seal squeeze increases, it leads to decreased permeability. Externally lubricated O-rings will affect permeability and lead to contamination.
Load – Many O-ring buyers overlook this factor. It pushes on different sides of the grove like the compressed sides of a spring. It may compress them up to 30%. Use a durometer to measure deformation. Some low-pressure projects need durometer compounds. On the contrary, higher-pressure applications need to depend on more durometer compounds.
You can now start searching for the best O-rings for your project. If you have not found the appropriate O-ring size, customisation is the right solution. A reliable O-ring supplier in Australia will help you find the desired size for your application. O-rings are customisable through moulding, machining, and other methods.
