Nextruder twists the filament as it feeds?  

RE: Nextruder twists the filament as it feeds?

Interestingly, I thought I had this problem, as I saw a loop of filament after a print.  So i carefully unloaded the filament from the extruder and held it to my nose as the directions above say to do so i could watch the twist relax.  And to my surprise, there was no twist!  In my case, its just that as the filament unwinds from the reel, it naturally forms loops.  The stiffer the material (ie PETG), the more likely it is to do it.

I could recreate the exact loop by just pulling a length of filament from the reel, and letting it do what it naturally wants to do.  I also get the loop when the Z axis rises up after printing, as the filament doesnt roll back on the reel.

I dont know what to do about it, if anything.

RE: Nextruder twists the filament as it feeds?

That is quite different from what I had. Mine was clearly twisting up, even with short 45 minute prints.  After re-printing and replacing the parts listed above, I finally had the chance yesterday to run a longer ~7 hr. print with the same PETG that was giving me trouble and this time there was absolutely no twist.  The new parts solved the problem entirely. 

-J

RE:

I also have this problem and until now, I never was able to fix it. Also printed the parts mentioned above, didn't help. Will try to tinker with the screws a bit further. But in my opinion it can't be the case that you have to adjust the tensioning screws that precisely. Also my OCD will kick in when the screws aren't screwed in the same way.

It also seems that the nextruder parts are designed badly from scratch, since the MMU3 needs to have PCCF and MJF printed parts:

https://blog.prusa3d.com/mmu3-2024-update-and-dev-diary_96103/

https://help.prusa3d.com/guide/9a-mk4-nextruder-mod_683106

Maybe MK4S will fix that?

RE: Nextruder twists the filament as it feeds?

I tinkered with screws, re-printed parts etc - after which I thought it was resolved, but then noticed that it happened more with some filaments and less with others. I also noticed it happened a lot more when I loaded a spool on the right side of the holder then on the left.

All this when using ONLY PLA Prusament then entire time. 

RE:

Posted by: @jvasileff

To understand steps 4/5, imagine placing the end of the filament back in the extruder, and consider which screw must be tightened to impart the same clockwise or counter-clockwise twist you identified in step 3. The filament will twist in the direction of the tighter screw.

Just to make sure if I'm doing this right as I'm not directly using your method. 

I can see the filament twisting counter-clockwise while printing. So I am looking at the extruder with loaded filament and the filament twists counter-clockwise. Then I'll have to tighten the screw which is farer away from me?

The thing is: No matter if the screws are even or the screw at the back is more tighened, the filament always twists counter-clockwise while printing.