Filament Won't Unspool Freely

Bambu Lab P Series Troubleshooting
1

Hi -

I have a P1P, and I am experiencing that the filament won’t “unspool” or won’t easily come off the spool towards the end of the spool. Everything is fine when I open a new spool and start printing. When I get down to about 1/8 of the spool left, somehow the filament gets kind of tangled, and/or trapped and won’t feed. When this happens - it messes up the print. But I know it’s this trapped filament that causes it because I cannot spin or turn the spool.

I mostly use PLA or PLA+ but I haven’t noticed any difference (I have the same issue) with other filament types when I use them.

Anyone else run into this?

Any suggestions?

Thanks

AJ

2
  • What brand are the spools or the filament?
  • Are the spools made of plastic or cardboard?
  • Do you use it with an AMS? If so, which one?
  • Do you get an error message? If so, what is it?
  • …maybe post a few photos to go with it.
3

Thanks for the reply. Here’s some answers to the questions:

  • Mostly Inland brand (from MicroCenter) - sometimes Polymaker
  • Mostly carbodard
  • No AMS, just the original spool holder with my P1P
  • No error message - the filament gets “trapped” and won’t spool out, and the print messes up, or sometimes the print head keeps printing but nothing is coming out

I do have a dryer that I dry out my filament with. But I am not certain why, when it gets down towards the end of the spool it gets

5

The filament sensor on my X1C (no AMS) only detects when filament is present in the tool head— it cannot sense if the filament is moving. So when the extruder cannot pull the filament because of a tangle, the head keeps moving with no extrusion.

I’ve never had a spool that came from the factory with a tangle. In one way or another, I caused all of them.

My number one cause for tangles is letting go of the filament end. It can spring back and slide under another wrap, forming an overhand knot around the spool. If the outer wraps are loose, the filament may unspool properly for a while because the cross-under point will rotate around the spool. However, eventually the knot will tighten and the spool cannot rotate. So, keep the filament end secured at all times. If it’s not in your fingers, it should be in a clip, through a hole, or in the PTFE tube.

I’ve also had problems if the outer wraps are very loose and find their way outside the rim of the spool, wrapping around the external spool mount. Check for excess slack after loading.

Drying filament at too high of a temperature can also cause it to fuse to itself.

6

Yes - I agree.

The sensors know if there’s no filament, but it’s not checking if the filament is feeding or not.

I suspect you’re right, I pulled a spool off, and didn’t keep the end under control or something…

Thanks

AJ