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Filament always breaking

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As a French user, I've already asked this question on the French page, but I can't find any solutions. Here is a photograph of the problem :


I just can't understand why my filament is always breaking at the same place.

It's the Ultimaker PLA I received with the machine. I let it on the machine all the time, but the room is regularly aired and there isn't any source of humidity.

I have to wring and brutalise it to break it with the bands.

I can print what I want without problems, I sometimes hear some noise comming from the feeder but don't know if it's normal.

Then, once the print is finished, I have to pull the filament out of the feeder and to use another. It's often broken where you can see on the photo and a few centimeters higher.

I hope you understood my English.

Thanks in advance.


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Check that the black plastic bearing of the feeder moves freely. Also if the extruder ambient it's hot the pla might soft on a heavy retraction print but on umo feeder since its apart that hardly happens. I would release a bit the feeder tension, clean the knurled bolt and check the black plastic bearing to see if it's really round, I had one at the beginning that was 'marked' and it was marking and slipping.

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The bearing moves freely.

I must say that the feeder doesn't move really smoothly. I can see little marks on the filament.

My bearing is round.

But I just saw that : image.thumb.jpg.72b4a8f08e3b3e6c4f1f46b3a9b5cfda.jpg

It seems the problem doesn't come from the feeder, because I pushed the filament until the nozzle since it always breaks.


Edited by Guest

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It's the filament. I think it's too dry. Or too old. I have some older filament that does this. I had to throw it away. Take a small piece of filament - say 10cm. Take another piece of brand new filament. Break them both in your hands - the new filament should be much more able to bend without breaking.

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I have air conditioning in the summer so the humidity isn't too extreme. In the winter it gets pretty dry - but never store your filament with for example a bowl of rice. It will get so dry it starts breaking up. I store my filament in large plastic boxes and when I open a new filament package I toss the desiccant packet into the box. I often leave a spool on a printer for a few weeks without changing it or putting the filament away but in general I try to keep filament boxed up.

I really don't understand what makes filament brittle. I have many spools of filament from different manufacturers and it has only happened to me once so far. It might not be related to humidity and instead related to age. All I know is if you take a piece of unused filament and bend it you can feel the difference. Good filament should not break easily.

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