As i wrote i hope i have a solution for my z-problem. Sintratec told me that i have an old version of coupler. The coupler is flexible. Depending of the position there is sometime more force needed to move. Then the system is swinging. Now i have got an infexible coupler. We will see.... I think in the next day i will see more... I have to recalibrate my laser, because some screws get loosen. (laser holder :-() Losen srews seems to be the biggest problems with the printer. You tighten the scews. You print 2 or 3 times. some screws are not tighten anymore....I have a call with Sintratec about this problem. But i think we have not realy a solution. I is a temperature problem....
@fred_dot_u: my core is fitting very well to the had. The clearancy is very exacly to all parts.