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.

    • DreadPotatoOPEnglish
      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?

        • DreadPotatoOPEnglish
          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.