I tried printing with PETG yesterday, and I noticed that it intermittently stops moving during the print for a few seconds. It doesn’t throw an error or anything, just stops and then after a few seconds resumes as if nothing happened. But this creates huge blobs where it stops. It only happens when printing PETG, not PLA. Could this be caused by a filament setting in my slicer? I’m using prusa slicer. I inspected the gcode and there are no stops, pauses or color changes etc. in it. The behaviour happens both when printing from octoprint and directly from SD card.

Edit: these random intermittent stops are 10-20 seconds long, causing massive blobs from oozing filament.

Edit 2: so it seems to not actually be a PETG specific issue, but rather a model size/speed issue. I can get it running without stops if I just reduce print speed. When I crank speed to 100% I start getting these weird 10-20 second long stops.

So I’m overloading the controller with a lot of gcode commands in rapid succession? I’m running at slightly lower than manufacturer default Max.

SOLVED: the gcode resolution was set too fine, I increased it from 0.0125mm to 0.5mm as described here and the stuttering disappeared.

  • seasick@lemmy.worldEnglish
    3·
    11 months ago

    I got a farfetched theory … Maybe your printer is underpowered. Printing PETG requieres a higher temperature and thus more power. This is absolute guesswork, but you could try to disconnect your printer from the power outlet and tighten the screws for the power connections going from the power supply unit and going into your printers main board

    • DreadPotato@sopuli.xyzOPEnglish
      1·
      11 months ago

      It still happens with low temps that are in PLA range. I tried a temp tower starting from 220°C, so the upper end of PLA temps, and it still happens. I can print PLA with 220°C without stuttering, so I don’t think it’s a power issue. But I’ll check nonetheless.

      It happens randomly, it may do several layers without stopping at all, but then it suddenly stops. It happens often, but not at the same spot, and not with fixed layer offsets.

      • seasick@lemmy.worldEnglish
        1·
        11 months ago

        Did printing with PETG ever work with your printer?

        You could create two gcode files for the same model, one for PLA and one for PETG and see if something stands out in their difference.

        • DreadPotato@sopuli.xyzOPEnglish
          1·
          11 months ago

          Did printing with PETG ever work with your printer?

          I have done a few prints in PETG before, only 2 or 3, but they didn’t have the issue.

          You could create two gcode files for the same model, one for PLA and one for PETG and see if something stands out in their difference.

          Yeah I was planning on trying this when I get home.

      • rambos@lemm.eeEnglish
        1·
        11 months ago

        I dont use pruca slicer, but had simmilar issues with ArcWelder plugin in Cura. Disable plugins if you use any and maybe try another slicer for testing

  • jagoan@lemmy.worldEnglish
    1·
    11 months ago

    If it’s fine with PLA then my money is on profile issue. Use your PLA profile, and just change the temperature. If that works okay, start tuning for PETG from that point. And delete the old PETG settings.

    • DreadPotato@sopuli.xyzOPEnglish
      2·
      11 months ago

      I did some more testing, also with different slicers, and it seems to not actually be a PETG specific issue, but rather a model/speed issue. I can get it running without stops if I just reduce print speed. When I set speed to 100% I start getting these weird 10-20 second long stops.

      So now in thinking it’s the controller locking up because it’s overloaded by too many small movmeent gcode commands in rapid succession?

      • thegreekgeek@midwest.socialEnglish
        2·
        11 months ago

        Yeah I had an issue with this trying to print some ornaments in vase mode. I adjusted the cura profile as detailed HERE and it seemed to take care of it.

        • DreadPotato@sopuli.xyzOPEnglish
          1·
          11 months ago

          That solved it, printing with PETG was just a strange coincidence then, but I’ve never seen this before.

        • DreadPotato@sopuli.xyzOPEnglish
          1·
          11 months ago

          Yeah maybe that’s what’s causing my issue, although it’s a bit more extreme in my case than his. I’ll definitely give that a try.

    • DreadPotato@sopuli.xyzOPEnglish
      1·
      11 months ago

      It’s an anycubic Kobra 2.

      It’s not small blobs like here, it’s huge blobs because the printhead doesn’t move for 10-20 seconds, so filament from the chamber keeps oozing while it just sits there.

      • TwanHE@lemmy.worldEnglish
        1·
        11 months ago

        Thinking about this again, could it be you have something like “wait for layer time” on and a very high minimum layer time set for your petg profile?

        • DreadPotato@sopuli.xyzOPEnglish
          1·
          11 months ago

          I was overloading the controller with gcode commands due to high gcode resolution. I dug a little in to the terminal and could see that locked it up due to a checksum mismatch of commands when using octoprint. I’m guessing a reading speed/buffer issue is the cause when using the SD card.

          I decreased resolution from the profile default 0.0125mm to 0.5mm and it went away. I’m going to see how fine I can set the resolution without introducing the stutter, but at 0.5mm it still looks good.

          I was potentially trying to execute 24,000 gcode commands per second with that resolution when moving at max speed, now it’s down to a more manageable 600 commands per second.

      • TwanHE@lemmy.worldEnglish
        1·
        11 months ago

        If its stopping 10 to 20 seconds there’s definitely something in the gcode making the printer hang. I’d try slicing the file again with a different slicer to be sure.