I’m trying to diagnose what tuning I need to get a smooth top layer on a solid print.

The picture you see is a 50mmx50mmx1mm square (cube([50,50,1]); in openscad) printed with a .4 nozzle. (5 layers)

For tuning on the problem, I have looked into:

  • z_offset – tried all kinds of values and if I reduce it anymore, it doesn’t squish into the bed and the center part is exactly 1mm – so unlikely to be that.
  • bed level – bltouch is working well
  • extrusion (esteps or rotational_distance) - played with this a great deal and any less and i start to have under-extrusion in the center area.
  • different filament – same with PLA, PETG and ABS
  • Different slicer – same with PrusaSlicer or Cura
  • Different speeds – one on the left was printed at 20mm/s – the right was printed at 150mm/s

I also cant find any guides out there that show this issue. Anybody with some suggestions or threads I can pull?

  • LazaroFlim@lemmy.filmEnglish
    6·
    1 year ago

    Pressure advance will solve some of your issues here. When reaching a corner, the head slows down but the filament is still pushed too fast and so it overflows. Pressure advance (in Klipper) can compensate for that.

    • tenzen@lemmy.caOPEnglish
      2·
      1 year ago

      I’ll check that out. I installed klipper yesterday for S&G – actually quite liking the flexibility it gives me. I see the guide.

      • LazaroFlim@lemmy.filmEnglish
        5·
        1 year ago

        Welcome to the deepest rabbit hole in 3D printing! Klipper is nice on the surface and absolutely mind blowing when you dig deeper. If you’re programming savvy, you can make it do basically anything. You can even install a script that runs shell scripts on the pi from the printer. You could make it control your coffee maker via home automation if you wanted. Lol. Anyways. Pressure advance is the key here.

        • tenzen@lemmy.caOPEnglish
          4·
          1 year ago

          Oh boy… Yes scripting comes easy to me. It’s why my default is openscad for making 3d models. :). I’m printing the pressure advance cube model now.

          • tenzen@lemmy.caOPEnglish
            1·
            1 year ago

            So… I still have some tuning.

            I learned that you need to adjust retraction and z offset again after implementing pressure advance… But I’m close now.

  • de_ninja@lemmy.worldEnglish
    4·
    1 year ago

    Seems like it’s squishing when the printhead decelerates and accelerates again around the corner. Perhaps the temperature is too high so too much material oozes out when speed is decreases?

    • tenzen@lemmy.caOPEnglish
      2·
      1 year ago

      I agree, not just the perimeter but also when it’s going back and forth to fill in the centre area. I’m not sure how to address it – maybe the pressure advance settings LazaroFilm suggested. I’ve also tried printing at a series of different temperatures…

      • de_ninja@lemmy.worldEnglish
        1·
        1 year ago

        That’s what I meant, have you tried just decreasing the printing temp by 10 degrees and then printing another square and comparing the result?

  • rambos@lemmy.worldEnglish
    3·
    1 year ago

    It looks like overextrusion, but Im not sure. Did you change overlap settings?

    I would try with taller cube to eliminate 1st layer error. You might be overextruding, but due to higher nozzle distance your first layer can still look perfect

  • Guy_Fieris_Hair@lemmy.worldEnglish
    2·
    1 year ago

    Looks like the edges are lifting from the bed a bit? What is the bed temp? Also, maybe lower the z offset? Doesn’t seem to be geting enough squish maybe. Hard to tell from the pictures.

    • tenzen@lemmy.caOPEnglish
      1·
      1 year ago

      in those two cases, they are PETG and bed temp was 80. The curved edges were caused by me removing the print from the hot bed… not lifting off during the print.