Another rather common type of O-ring failure is Abrasion. This usually is found only in dynamic seals subject either to reciprocating,
oscillating or rotary motion. Possible causes of O-ring abrasion are listed below.
In general, Abrasion of O-ring seals is caused by one or more of the following:
- Improper finish of the surface in dynamic contact with the O-ring. This surface finish may be too rough, acting as an abrasive,
or too smooth, causing inadequate lubrication due to inability of surface to hold lubricant.
- Improper lubrication provided by system fluid.
- Excessive temperatures.
- Contamination of system fluid by abrasive particles.
Suggested solutions to problems caused by Abrasion are as follows:
IDENTIFICATION OF FAILURE
- Use proper surface finish.
- Provide adequate lubrication by use of proper system fluid.
- Consider use of internally lubricated O-rings to reduce friction and wear.
- Check for contamination of fluid and eliminate source. Install filters if necessary.
- Consider change to O-ring material with improved abrasion resistance.
The O-ring which has failed due to wear thru abrasion usually exhibits a FLAT area on the side of the seal which was in contact with the dynamic surface.
Frequently there will be wear lines on this flat surface parallel to the direction of motion. Abrasion failure may be differentiated from compression set
failure in that with abrasion, only one side of the O-ring will be flat or worn while with compression set failure, both sides of the O-ring are equally deformed.