Filament broke?

I was 4 hours into a print and I noticed my printer was moving but not printing. The filament must have broke off at the extruder just past the gear. It was spiraling around outside the extruder. I stopped the print and tried to feed it back in but it wouldn’t go. I printed a bit of something else to try to clear the tube and then was able to feed the filament in. It seems like its working now.
I don’t know what would have caused this to break off. Everything was printing fine.


PLA will get very brittle when it’s wet. is that what you are printing? I have a sample piece here that’s not flexible at all. it’s been out of the package for months and breaks like it was made of compressed flour.

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I keep the filament in freezer bags with a desiccant pouch.

I can only tell you my experience. Also, I think people underestimate how much desiccant it takes to get the moisture out of the air and also draw it from the plastic.

I do as well, however it on occasion comes wet. The freezer bag might be ok at holding the humidity but not so good at reducing it. You also need to stay on top of swiping old for fresh. I use indicator gel, it is far more toxic but I understand the risk and accept that for the ease of use.

I wonder sometimes if in shipping it doesn’t get screaming hot and start to crystallize. I have had some rolls no matter how long in the dryer it was it was very brittle and prone to breaking.

I just tried the same print with the same filament and it did the same thing a little earlier. I’m going to try the same print using a different filament and see what happens. Will update tomorrow.

Tried different filament and it messed up about the same place. I think the file I’m printing is too detailed and the extractor is getting a great workout. The file is intended for an HO model and I’m reducing it by 54% so the shingles on the roof are too small and detailed. The gentleman that made the file sent me a new ‘roof’ model but with less detail. I will update when I print it.

My experience is different but…

I found every large or long print the filament would fail to extrude part way through. It would just stop extruding and sometimes would start again sometimes would not.

What I found was the extruder was overheating and stopping completely, sometimes it would cool down enough and start again, sometimes not.

This has nothing to do with broken filament but your last post doesn’t sound like the issue is broken filament.

OR could it be reaching a given height and be stressing the filament and breaking it because the filament path is poor?

Are you using retraction?
If the filament that breaks shows grinding marks, you may be doing too many retraction operations in the same spot and grinding the filament to a point where it is too thin to take one more retraction.
If that is the case you may need to change the retraction settings to reduce the number of retraction done within a short segment of filament.

An HO scale model with lots of details sounds like the kind of print where a lot of retractions could be done without extruding very much filament so that the extruder would be working very hard while repeatably grabbing the same bit of filament to retract and then push it tiny distances. Each retraction/extrusion cycle grinds off a bit of filament.

Out of curiosity, do you have a link to the model?

I can’t copy and paste the file. I don’t know how to send it to you any other way.

Thanks for trying. I take it then, that it’s not something you downloaded off Thingiverse, Cults3D or any of the other publicly accessible web sites?

By the way, if it’s not publicly available (ie. if you have to pay for it to access it) then it’s not something you should be sharing anyway.

I asked about it because the only HO model I ever had that would consistently break filament was a parametric tree off of Thingiverse. It made some nice trees until you noticed they all had remarkably flat tops (where the filament broke) and I could probably have fiddled with the retraction settings to get it to work, but I wasn’t that interested at the time.

Actually it is on Thingiverse. search karumble. It’s a church and then just the roof. It’s HO scale but I reduce it in Cura to 54%. It is free for anyone to use. He has some amazing buildings on there including most of a town.
It you print it, let me know.

HOLD IT, KARUMBLE doesn’t work.


Did you ever find that ‘church’ file on thingiverse?

Actually, my town already has a church so I didn’t need to print it. In fact I couldn’t find it, but I see now that you’ve edited the post with a corrected name.

I would suggest printing it vertically, as you would with a lithopane. That would eliminate the retractions.

Kabrumble sent me a new roof file that was basically plain and it printed great. He has some amazing building files.