Installation Damage

Many O-ring failures can be directly attributed to Improper installation during assembly. In spite of its simple appearance, the O-ring is a precision device requiring care during installation. Some of the more frequent causes of O-ring failure due to careless handling are listed below

 

FAILURE ANALYSIS
Damage to an O-ring during installation can occur when:
  1. There are sharp corners on mating metal components such as the O-ring gland or threads over which the O-ring must pass during assembly.
  2. Insufficient lead-in chamfer.
  3. Blind grooves in multi-port valves.
  4. Oversize O-ring on piston seal application.
  5. Undersize O-ring on rod application.
  6. O-ring twisted/pinched during installation.
  7. O-ring not properly lubricated before installation.
  8. O-ring dirty upon installation.
  9. O-ring gland and/or other surfaces over which O-ring must pass during assembly contaminated with metal particles.
  10. General carelessness.
PREVENTION/CORRECTION
Probably the best way to prevent damage to O-rings during installation is the use of good old fashioned "COMMON SENSE". There are however, some specific solutions which are listed below:
  1. Break all sharp edges on metal components.
  2. Allow a 20° lead-in chamfer.
  3. Check all components for cleanliness before Installation.
  4. Tape all threads over which the O-ring will pass.
  5. Use an O-ring lubricant such as Parker 0-Lube or Parker Super 0-Lube if its use will not contaminate system.
  6. Double check O-ring to insure correct size and material.
  7. Be CAREFUL.
IDENTIFICATION OF INSTALLATION FAILURE
It is difficult to properly illustrate the many possible results of Installation Failure. However, below is an example of a common failure mode, the "Skiving" of the O-ring surface due to cutting by metal components. These cuts are usually very clean as if made with a very sharp knife. Another indication of bad installation will be small cuts or notches on the O-ring. In almost all cases, the damage will appear on the surface of the O-ring AWAY from the bottom of the O-ring groove.

 

Installation Damage
Installation DamageExample
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