The stick-slip effect is derived from the terms “stick” (sticking) and “slip” (gliding). The phenomenon describes the jerky sliding of solids, which slide against each other (sticking is significantly greater than sliding friction).
This unwanted effect can also be observed at dynamically stressed sealing. Due to high pressures, higher temperatures and longer standstill times there will be a more aggravated resolution of the armature. The “sticking” mainly leads to
– a higher power input in the starting phase at electro-magnetic valves
– increased pressure at pneumatic and hydraulic valves or even to
– a malfunction and following PTFE slide coating
Therefor appropriate measures are needed to avoid such an effect as use of
– plasma treated elastomer surfaces
– combination of plasma treatment and following carbon treatment
– combination of plasma treatment and following fluor treatment
– combination of plasma treatment and alternative special coatings
– friction modified compounds with a friction-reducing polymer filler
– reduction of tolerances and less pressure of the seal seats
– design optimization of the sealing geometry
Depending on the special case you will have to decide which of the named processes are best to solve your stick-slip-problem.