Failure Pattern
Of the various types of seal failure, this 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 the 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