Filament jamming on spool

Bambu Lab A1 Series Troubleshooting
1

A relative newcomer to 3D printing - I bought my A1 Mini in August along with 5 spools of PLA Basic. As it was dipping my toe in the water, I didn’t go for the AMS Lite and kept things simple.

All was well to start with and I was alternating between two spools, black and grey, for various print jobs. The grey was the ‘go to’ as it had a slightly better feel to it than the black but when I reached the last third of the reel I started to get periodic jams on the filament that would stop the print, with the filament line to the printer locking under the next couple of winds on the spool.

I put this down to newbie error the first time and use a bulldog clip to hold the filament in place after unloading the filament and replacing the colour. The second time I happened was during the first longish print I had set up to run overnight. It resumed once I untangled the filament and reloaded, but there was a tell-tale layer line. As it was the Bambu Statue print, that wasn’t great. I played with the settings for layer height and printed another. That was 10 hours and got 23% before another jam. Again, I unloaded, pulled the filament back through the jam and reloaded. High points developed on the support trees, presumably due to the finer layer height, and the print was knocked off the plate at 50%. Refine the layer height for the top of the statue only and start again, and about half way through I could hear the spool stopping moving freely so snipped the filament, unravelled the jam, and was able to re-feed the filament into the tube so that the print was continuous.

OK, so I got a duff reel. It’ll happen at some point, and I pulled the short straw soon in to the experience. I thought I would alert Bambu, so sent them photos, the logs, and the batch number of the filament.

Off I went to Makerworld to grab some STLs for clips etc and finished the gray and opened a new spool of white basic PLA. I noticed the winding was haphazard in the shrink wrap, but that’s just what it is and I had nothing to compare to, so loaded and within 5 minutes of printing the filament jammed. Different batch number, so more photos of the other spools (all haphazard windings) and when a quick order of more filament from Amazon arrived I compared. Nice even windings. I haven’t tried the new stuff yet.

I have searched and read here and on reddit to see if there are answers but haven’t found anything, so…

Has anyone else experienced this problem where the filament appears to be wounded under itself?

Should new spools be prepped in any way? (I’ve read refills should be squashed down, but these are loaded spools, not refills)

How can you plan for it without unwinding and rewinding a spool?

Is is just one of those blips that are part and parcel of 3D Printing?

Bambu seem less bothered and have suggested I send more photos if it jams again.

I’d welcome any advice and thanks in advance

When asking for help, please provide as much information as possible about your inquiry.
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  • Detailed description of the problem
  • Printer model used
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  • Type of filament used
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  • .3mf file (if the file can be shared)
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2

It is very rare that a spool is wound incorrectly, even though it looks as if the filament wind is untidy. Generally it is user error. If the end is not in the printer, then it should be attached to the spool. The time in between, keep a firm hold on it. If you do let go of the end, then unwind maybe a dozen turns, to make sure that the end has not gone under a previous turn.

The other aspects that can make it not unwind properly, is if there has been too much tension when it is made, the upper layers pulling down below the others, in particular at the edges of the spool, and excessive heat. Some consumer grade filament dryers heat unevenly.

3

Glad to hear it is rare. The first time it happened I did clock it up to newbie error, but used bulldog clips straight after. The jam was always on the same side of the spool of grey. If It hadn’t happened to the white within minutes of loading from a freshly opened spool (so no chance to unwind before going into the load tube) I would have still said it was mishandling.

With the grey, because it was in the last third of the spool, I think you’ve hit the nail on the head with there being too much tension when winding originally, pulling filament through earlier winds. I’m monitoring the white. My dehydrator only arrived yesterday, so I haven’t had the chance to add that into the mix, but is certainly something to look out for. Thanks.

4

The A1 mini is fantastic and I also love the simplicity. I also use an X1C with an AMS and have experienced a jam or two due to poorly wound filament. I don’t know of any way to avoid it, but luckily the problem is rare.

5

Another thing to watch out for is if vibration is causing the spool to unwind during printing.
I found one particular spool did this on my A1 and caused a jam. After clearing the jam I wrapped a bit of kitchen towel around the spigot to add some friction and had no further problem with that roll.

6

I was less bothered about vibration and more about how much movement there was of the spool on the holder. The diameter of the spigot is much less than the spools. I was actually printing this: Low friction spool holder by rogerquin - MakerWorld when the white filament first jammed. I’ve also mounted the spool at the top using this: A1 Mini handle with original spool holder by D4V3IG - MakerWorld as I can see the spool movement far easier and access it better if there is a jam.