Solutions for Failure without Visible Evidence on Seal

Failure Pattern
Of the various types of seal failure, failure without visible evidence on the seal is among the hardest to diagnose because the result of the problem is not visible on the O-ring.

Problem Sources

• Lack of compression
• Tolerance stack-up
• Eccentric components
• Parting lines/flash
• Improper seal/gland volume relationship

Suggested Solutions

• Maintain recommended compression range for the application
• Identify the amount of stretch as it reduces the O-ring cross section with increased stretch
• Determine the component tolerance stack-up as it directly affects the seal cross section
• Consider maximum component shift in design to ensure that compression is still contained within recommended compression range
• Avoid parting lines in O-ring grooves as they tend to be areas of flash and mismatch
• Ensure that the O-ring gland volume surpasses the O-ring volume to allow for seal expansion without seal detriment

O-RING RULE OF THUMB #3

To create seal compression, the groove depth must be less than the seal cross section. To compensate for this compression, the groove width must be greater than the seal cross section. » Learn More