I cant get my Anycubic Kobra 2 with Klipper to print correct. The first mm of each layer are faulty, resulting in a bad tooth in gears.
I tried to slow down the print, tried to minimize/deactivate retraction, fiddled with z offset and first layer height, lowered bed temp, altered the extrusion rate. Nothing works. Everything else seems fine, slim z seam, nice walls, no over/underextrusion.
Anyone got a hint how i could fix that?
Edit: I cancelled that Print, the Problem is only in the first tooth:
the tooth in the marking should look like the ones above it.
Try adding a skirt to your print in your slicer. That should ensure that your nozzle is good and primed by the time your printer actually starts printing the first layer of your part.
I don’t know in what order that layer was printed, but it looks to me that no material was leaving the nozzle throughout the 7:00 to 3:00 or so portion of it.
I canceled the print. Its only the first tooth thats not printed correctly.
In the second photo of the fully printed part it’s hard to see the issue.
Looking at that first layer, the first tooth looks very similar to the internal perimeters of the teeth that have had two perimeters printed.
Is it possible the first pass on the first tooth is printing an interior perimeter whereas the first path on the other teeth is printing a different perimeter? What does the first layer look like when you let it finish the layer?
And could you please provide a picture of the first layer as rendered in the slicer?
In the first photo the outter perimeters were completely print and the inner started to print. The outer perimeter from the first tooth is missing, so theres only the inner one. In PrusaSlicer the perimeters are correct, the nozzle moves correctly but no filament is coming out. It begins with the second tooth. I let the nozzle draw 5 lines prior to the printing so the pressure in the hot end is correct. I guess its a retraction issue, maybe the slicer retraction settings are ignored by the firmware, ill look into that tomorrow.
Anyways, here a picture of the first layer:
Okay, thanks. I’m afraid I don’t have any further insight here, there’s obviously either a problem with the G-code or how the printer is executing that G-code, I suspect your idea about retraction might have something to it. Could you provide the G-code file? I don’t know if I will be able to get much out of it, but there are a number of G-code viewers and simulators that can help you understand better what’s going on.
Thanks for your offer. I tried cura slicer and there the problem is gone. So it is a problem in PrusaSlicer. Here is the gcode, please dont put too much effort into it.
https://filetransfer.io/data-package/i7JoxlFl#link
Oh, well sounds like it was a slicer issue then. I assume it must’ve been retracting too much between layers. I’d be interested to understand why, but if you’ve fixed it I don’t feel any need to investigate. Congrats on fixing it.
It’s a retraction issue. If the layer starts there and you are missing first few millimeters of filament, that means you’ve retracted filament too much. If it’s only on the first layer, adding skirt will help prime the nozzle. But if it’s present throughout the entire print and all the layers start there, which it seems to be the case, it’s retraction issue.