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ptfe jam  

Active Member
ptfe jam

being printing with pla (stock temps settings) a voronoi model print inherit with many retractions and I had ptfe tube clogged mid print

after  replacing  ptfe found the clog right where ptfe meets nozzle. it had also slightly deformed ptfe tube by enlarging it’s diameter by aprox half mm

any ideas on what might have caused it?


This topic was modified 1 year ago by haris
Posted : 28/01/2021 10:19 am
Eminent Member
RE: ptfe jam

Seems this is coming from too many and too long retractions.

If you have many retractions the filament is always moved back and forth transporting heat back into the hotend feeder. Especially if retraction length is very high, melted filament is pulled into the upper tube part. It can happen, that due to the lower temperature the filament gets stiff again and can block. If the extruder then is pushing in new filament, it can be deformed at the clog even more as it is still quite weak there.

I am surprise that you have this issue with PLA. It is more common with PTFE due to the higher temperatures and less stiffness of filament.

To avoid clogging needs a good temperature management throughout your whole hot-end. So, it depends on your hardware. 🙂
What you can do for your prints is to:

  • generally avoid excessive retraction
  • decrease the retraction length
  • think of reducing the temperature which could decrease oozing and the need of much retraction.

What is your retraction length?


Posted : 30/01/2021 7:52 pm