On the bottom of my prints, there’s an area of underextrusion and I can’t figure out what’s causing it.

I first noticed it when I switched back to a textured PEI bed while trying to print ASA. It’s on 20x20mm squares, and it’s on the test print for setting up pressure advance… But only on the left-most object.

It’s the same even if I add 2 lines of skirt or not. (In addition to my KAMP Voron purge.)

It happens everywhere on the bed that I’ve tested. It happens to PLA, but it harder to see. For ASA, it’s very obvious. For PLA, it’s almost as smooth as the rest of the surface, but it’s there if you know what you’re looking for.

I’ve only been printing PLA for quite a while now, so I don’t know when this started.

I’ve got an LDO Voron 2.4 with Tap, KAMP, Revo hot end. I’ve calibrated pressure advanced and changed the value, and I’ve tried different z offsets with the textured bed, which doesn’t change it. (But does change how good the rest of the bottom surface looks.)

Anyone got any ideas?

https://imgur.com/a/ggaZDMY

  • beeb@lemm.ee
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    7 months ago

    Interesting, that would confirm the pressure advance as the likely culprit (speed and acceleration are taken into account in the algo). Maybe your slicer has a bug related to this? If changing the value wildly does not improve or worsen it, then it might not be calculating what it’s supposed to. Can you try another slicer?

    • William@lemmy.worldOP
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      7 months ago

      I turned pressure advance to 0 in both Orca and Klipper, and saw no difference. :(

    • William@lemmy.worldOP
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      7 months ago

      I used an older Cura that I already had installed (instead of Orca 2 that I’ve been using) and the underextrusion pattern is different, but still there.