Filament is breaking off in my extruder every print
As the title reads. I, seemingly all of the sudden, cannot get through a print without the filament either slipping or breaking off entirely in the extruder. My current set up is as follows:
Prusa XL 2 Tool Head with XL Enclosure
Creality Dual Spool Filament Dryer
This issue is occurring primarily in tool 1 but has happened in tool 2 as well. It is worse with pla but also has occurred with petg. I have done some research and lots of people in the community are saying that the issue is high friction in the ptfe tube caused by heat from being in the enclosure. This is made worse by extending the ptfe tube for the creality filament dryer. What I am wondering is, is this common here and are there any work arounds. I suppose I should go down the path of upgrading the ptfe tube to something that works in the enclosure but I am especially wondering if Prusa is aware of this and what someone at Prusa thinks should be done. Just last night, 4.5 hours into a print, the filament broke off and the machine even failed to get through the filament change procedure. The printer "froze" after the filament was pushed through the filament sensor and I was unable to resume the print. I can provide .3mf files but I am merely trying to print in pla on standard settings. Nothing too fancy. Most complicated prints I do utilize pteg supports. I feel like this is a serious issue that may merit some attention from the Prusa team. Especially if the root cause is the ptfe tube not being able to withstand the temps in the enclosure. Any help would be appreciated. Thanks!
RE:
I had issues with 2mm id ptfe on mmu2 and changed to 3mm id ptfe, my mmu3 is now inside an enclosure, and the 3mm id ptfe is still working fine, if you are using 2mm id ptfe you could try 3mm id...
joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
Breaking PLA is almost always due to wet filament, check that your dryer is working correctly.
If you are printing abrasive filaments they will wear the inside of the PTFE tubes and eventually roughen them enough to cause extruder problems, (normal heat has little to do with the initial cause but slightly softens the tube and may speed the degradation) - if possible bypass the tube and feed abrasives from an overhead spool. If using it to connect an external drybox make the path as straight as possible. PTFE tubes are cheap and easy to replace.
Abrasive is a relative term, Carbon fibre, glass fibre, and metals are obvious but glow-in-the-dark is less so and filaments containing titanium white - white and some pastels - are also slightly abrasive.
Cheerio,
RE: Filament is breaking off in my extruder every print
Thanks. Yeah that's what I initially thought. The dryer is reporting 15% humidity at 50c during prints and the enclosure is reading <30% humidity. Unfortunately, it think @JoanTabb is correct and the ptfe tubes are the culprit. Will be swapping to larger diameter tubes soon and will report back. I am a little bummed that I have to do this as it will be quite a project to upgrade all the parts involved. Especially considering that I can't consistently get through a print without this issue occurring lol. I may have to use my work printer to print all the parts.
RE: Filament is breaking off in my extruder every print
I think you are right.
The dryer is reporting 15% humidity
You should really be aiming for 10% in the dryer, try drying for a little longer - you may not quite get there.
I doubt the diameter is fundamental to your issue unless you are working/experimenting at very high temperatures as so many others are working well.
Feed some filament to the printhead but don't load, disconnect the tube at the printhead and, without changing the bend, pull some filament through manually - is the resistance excessive? Does it differ between heads?
Cheerio,