One hour

...of searching for the mistake.

I think i found the issue, why the Ali wire wasn't transported anymore.

There was a fine layer of Ali remains in the structured surface gap of the roll. 

And through the higher pressure of the pressure ball bearing on the other side of the transport system, the wire got flat and caused to get stuck in the transport tube.

I cleaned the roll with a metal brush, cut off the wire that was still in the tubing and took it out.

The pressure roll was again adjusted and the wire was normally running now through the tubing.

Let me see how long it will work...