Uitvallende staaf bij aanvang printen

uitvallende staaf bij aanvang printen

That’s a bit vague …
I think you mean that one of the pushrods is falling of when he goes to the prime position (just before printing?)
There is a lot on the forum about that, but start checking that you build the Delta correct. (there is a solution guide here somewhere on the forum. Check that one, if everything is in spec.
Put some (1 or 2 drops/ bushing) machine oil on the copper bushings and ptfe oil on the magnetic balls (and cups). That should do the trick.