#1 How does abrasion occur with O-rings?
Particularly in dynamic applications, abrasion occurs due to contact between the O-ring and a harder mating surface. This continuous friction causes the O-ring to gradually lose mass.
In the long term, this causes the O-ring to lose so much mass that the O-ring becomes leaky and has to be replaced. As a basic rule, dynamically loaded O-rings should be replaced much more frequently than statically loaded O-rings.
It should also be noted that the abrasion of the O-ring can contaminate the medium. This is particularly important if the medium is a food product (e.g. milk).
#2 What can I do to avoid abrasion?
1. When designing a dynamic application, the compression should always be calculated as low as possible.
2. Reduce the friction by grinding or polishing the mating surfaces (the surface against which the O-ring seals).
3. Use O-rings with a PTFE anti-friction coating. These have an excellent coefficient of friction.