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Top Story: Important Considerations for Selecting Microminiature O-Rings

No matter what type of sealing application you are doing, it is very important to have the right ring for the job.  But there is more to the selection process than you might think.  Correct O-ring selection is the result of a number of design considerations.  These can include:

• Dimensions
• Chemical compatibility
• Ability to resist pressure
• Temperature extremes

The importance of these considerations is larger when the size of the O-ring is smaller. Since Microminiature designs are so small, there is less room for error.  This requires higher precision and tighter tolerances.  To help avoid problems, it’s crucial to pay attention to some of these basic sealing concepts when selecting a microminiature O-ring for your application.

Some things to consider:

Sealing Pressure – Sealing pressure is the force that is applied when there is compression of the seal between the mating surfaces.  This forms a gland itself and external forces are transmitted through the seal.  Physical barriers may form when this force causes the seal to fill all leak paths.

Low Pressure Sealing – In low pressure sealing, system pressure does not cause a noticeable increase in the seal’s sealing force.  Because this happens, all sealing force must come from the ability of the seal to deform and create a barrier by compression of the seal.

High Pressure Sealing – In high pressure sealing, system pressure causes noticeable increases in the sealing force to fill all leak paths.  This pressure activates the seal allowing the compression of the seal and surface roughness to become less important than they are in low pressure sealing.

For more information, download our MicrOrings brochure.