I currently have a strange issue with my UM2: The nozzle cloggs BETWEEN two prints! I finished a 2.5 hour print successfully and switched of the printer after the cool down completed. An hour later I wanted to start a new print but during the extruder priming phase, no material got extruded. I aborted the print, did a few atomic pulls and then could start the new print job. That one took 4 hours, also without any issues. But when I tried to start another one just an hour after the previous one completed, the priming did again not extrude material. I switched to the maintenance menu and tried to extrude manually but no luck. I then tried to clean the nozzle by sticking a 0.4 needle in while it was heated and after that I could extrude material again. Now the print also runs fine
![Rolling Eyes :roll:](./images/smilies/icon_rolleyes.gif)
What could cause this? What could block the nozzle just by not using it for a few minutes/hours?
The filament I use is a fairly new (<6 months old) roll of black Colorfabb PLA/PHA that was always stored in a sealed plastic back with silica gel when not in use.
BR Reiner