Igus bushings are usually oversized and if not correctly constrained (aluminum housing or well printed housing) will vibrate or bind to the rod as it moves.
Even if they are self lubricated, you should try to lubricate the rods (use dry lubricants) to see if it helps a little.
Edited 1 time(s). Last edit at 08/05/2016 09:21PM by ggherbaz.