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I've done a fair bit of looking around for an answer and have yet been unable to find one.

So here is my problem, after about 200-300 mm of extrusion, the PLA stops coming through the nozzle. When I pull the PLA out it looks like this. There are teeth marks going up the PLA and end with a small divot. The head of the PLA is slightly thicker than the rest of the PLA; approximately 1.9 mm.

Filament shape after taken out of hotend

I first noticed this when I thought that only the bottom layer was being printed. I moved to printing a small bullet and I got about halfway through the print before it stopped extruding.

Next I raised the Z position to about 100 mm to give me some room to work and I manually moved the PLA through the extruder with the dial. No problems until I hit the 200 mm mark or so. I've done this test 4 times now and failed at the approximate locations: 208 mm, 280 mm, 250 mm, and 325 mm.

Settings:

  1. Nozzle: 200 °C
  2. Bed: 60 °C
  3. Layer Height: 0.15 mm

Other things I have tried with seemingly no effect:

  • Turning off/on print cooling
  • reducing retraction to 2 mm from 6 mm
  • yelling out in frustration
  • reformatting the SD card (because who knows?)
  • brand new filament, older filament, middle aged filament
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  • $\begingroup$ Welcome to 3dPrinting.SE! Definitely a +1 for yelling at your printer/print :o) $\endgroup$
    – Pᴀᴜʟsᴛᴇʀ2
    Feb 12, 2019 at 18:00
  • $\begingroup$ Good that you have told us how much you managed to extrude each time... When you pushed to these points, what did happen? Can you show us a photo of a print-result where it? $\endgroup$
    – Trish
    Feb 12, 2019 at 18:12
  • $\begingroup$ Does the extruder stepper try to move? Did you try to push the filament by hand? $\endgroup$
    – jkavalik
    Feb 12, 2019 at 18:17

1 Answer 1

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Looking at the tread pattern on the filament, I think it's getting stuck. Note that the teeth marks get closer together as you go up the fillament, and the last one is a big divot, that looks like the gear trying to grab at it, and being unable to move it.

Are you seeing any drops in nozzle temp? I had a cooling fan kick in and drop temps low enough to prevent extrusion before.

Edit

From the discussion in the notes, heat creep was identified as a possible culprit, and seems most likely.

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  • $\begingroup$ good point... clog? $\endgroup$
    – Trish
    Feb 12, 2019 at 20:12
  • $\begingroup$ @Trish clog wouldn't have the consistent behavior of working for some amount, then stopping. It's something about the printer's behavior that kicks in.. there's nothing repetitively cumulative about what it does otherwise. $\endgroup$
    – kolosy
    Feb 12, 2019 at 20:24
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    $\begingroup$ Alternatively - it could be heat creep. If the filament gets too soft by the gear, then it gets harder to push the filament down, and at some temp, impossible. $\endgroup$
    – kolosy
    Feb 12, 2019 at 20:28
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    $\begingroup$ so, i might have just fixed it. Im doing a test print to see. I think the culprit is heat creep. When I put the print head back together I put the heat sync on backwards. (smart, i know). I think because the heat sync was on backwards it wasnt dissipating the heat as well, so i was getting melt higher up the PLA, which made it too fat to be able to continue extruding. This explains the pattern on the PLA as well. $\endgroup$
    – Nate4436271
    Feb 12, 2019 at 20:29
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    $\begingroup$ Did a few test prints and they came out successful! Thank you so much. I guess the heat creep softened the PLA which made it bunch up on one side and made it so that the teeth couldnt push the PLA down. $\endgroup$
    – Nate4436271
    Feb 12, 2019 at 20:56

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