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?

  • tenzen@lemmy.caOP
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    1 year ago

    Thank you everybody for leading me on the right path.

    As I had already installed Klipper, I decided to try the pressure advance calibration as suggested and it did take some tuning, but has improved quality immensely.

    In the end, here are the settings I changed: Klipper printer.cfg pressure_advance: 0.120

    PrusaSlicer:PrinterSettings:Extruder 1:Retraction Length: 0

    I still think I can tweak my z-offset and temperature and maybe further refine pressure_advance, but the results are quite a bit better than before.

    I used the Klipper guide for pressure advance: https://www.klipper3d.org/Pressure_Advance.html

    Original print on the left, print with the above changes on the right.

    Having said that, I think I might have been able to improve the results using a marlin firmware and working with my retraction setup – I use a non-default direct-drive extruder so the default settings of about 6mm are certainly incorrect.

    Also, into the future, i’ll check out the wear/maintenance on the nozzle – it is a good point and I havent changed it in quite a few prints.

    Thank you everybody!