Weird patern on my prints surface Anycubic Kobra

I recently got a Anycubic Kobra and i played a bit with cura settings and since then, when i print relatively big things, i got a strange patern forming at ramdom places on the surfaces of the prints. I belive the problem might be with the nozzle temp (at first i use to print PLA at 225°C but i reduced it to 215), some Cura settings i played with that i shouldn’t have, the printing speed ( i put it at 45 mm/s for the walls), and my last lead was the red screw on the extruder block that i don’t know how to adjust.


Cura has built in settings for many printers that are actually very good (since V 4.11). If it does for yours than try printing with them and see if it helps. 225C was way to hot for most PLA.

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Looks like underextrusion starting at the z seam. Do you have coast enabled in Cura by any chance? If not a too high coast volume, then your extruder is likely slipping on either retraction or unretraction.

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I don’t have coast on but now i have an idea of what’s the use of the red screw on the extruder block.
i m gonna run some test and i will check

HI @Oceanos

Welcome to the forum, Glad you found us.

A couple of suggestions for further troubleshooting;

If you reprint the same Gcode again will the same defect show in the same location?
If you take the same model and turn it 90deg in your slicer and reslice it, Will the defect stay in the same location physically on the printer or will the defect print in the exact same location on the print itself?


i can only answer your first question :
i dind’t have the time to test with this stl cause it takes 6 hours to print.
I previously tried it with another gcode and the defect showed at the same location but wasn’t exactly the same shape

ok, perfect, that may be enough

If the same defect or at least a similar defect is showing up in the same location I would be looking at the physical issues on the printer. I’ll be honest, Usually, it’s a nick or scratch in the nozzle itself.

You don’t have to see the defect in the same print, If you print a vase or something quick that shows the defect you are golden. Print it once, see the defect, change the nozzle, and print again to see if the defect is still there or gone. If it’s gone then I would go back to the bigger print.

If it’s model-specific you can always set up the print slice at Z -10 or Z -20 to drop the 1st half of the print through the bed so it won’t print and just print the part of the model with the defect.

If you have a look at the example I have here I have setup the model with a Z position of -2 so the first 2mm of the model are below the build surface.