I have a cheap bedslinger, an Anycubic Kobra 2, and generally it's a pretty decent printer at the price. I have flashed klipper FW on it, so I'm not using Anycubics FW.
I have issues whenever I try printing bigger parts, the first layer is always complete shit (see post photo).
Heightmap, measured with inductive probe
range is only 0.085mm from min to max, so it should be reasonably flat. The heightmap is automatically recalibrated and loaded as part of my print_begin macro.
Slicer settings for line width
I don't know if my printer just doesn't correct Z-height during first layer, if my line width settings are completely messed up or what is causing this, but the issue is only apparent on bigger parts with large contract surface on the bed.
[SOLVED] It was just Z-offset that was too low causing this. however when running the calibration routine from ellis3dp on first layer squish, the settings that looked good on the small calibration patches, looked like crap on bigger prints. I needed a bit higher Z-offset, but that solved it.
Is there a lot of crackling from the nozzle? It's heard of some filament absorbing trace bits of water that can cause gaps and bubbles like that.
No it's completely dry filament, I store it in dry boxes with silica, and always print straight from the dryer. There are also no other issues that is related to moisture in filament, it prints well except for the very first layer, and first layer is only an issue on large models. It's not limited to this specific filament.
This particular print is also printing well, as soon as it's beyond the first layer.
This adds even more credence to the idea of your nozzle being too close to your bed for your first layer.
Yeah it was just too close, but it was only really an issue on the larger prints (I don't make that many of those). The offset that looks fine on the smaller calibration patches looks like shit on the bigger prints.
I was able to find a good setting eventually though