• Printer: Kobra Max
  • Nozzle: 0.4 mm
  • Material: PLA
  • Slicer :Cura

I have printed 1 model 3 times with different settings (different temperatures and different bed temperatures).

  • Try 1: 190 °C / 50 °C
  • Try 2: 210 °C / 70 °C
  • Try 3: 230 °C / 50 °C

All 3 models show 1 "line" at some point. The models are smooth all around, but then there is this 1 line on each model.

What is this error called, please?

Photo of three printed models with the same printing error

enter image description here


2 Answers 2


This is the Z-seam, or just "seam". It's a consequence of the fact that the extrusion of each layer has to start and stop at some point rather than being a continuous path for the whole print (like it would be in "vase mode").

Depending on your retraction speed and distance, travel speed, linear advance/pressure advance tuning, and various slicer-level knobs, the seam can range from mild and nearly imperceptible to a giant bulge to a gaping hole in your print. Yours doesn't look terribly bad.

Most slicers (you didn't mention which you're using; knowing that could help get better answers) have options to control where they position the seam, letting you hide it in corners where possible or put it consistently along one edge of the model you don't care about.

  • $\begingroup$ Thank you! Do you have any idea where I could hide the seam for this knob? The knob is round. Edit: I think I will post a new question for this... $\endgroup$
    – tmighty
    Commented Oct 6, 2022 at 13:52
  • $\begingroup$ For anything that is meant to be round, you probably want to be thinking about vase mode $\endgroup$
    – MikeB
    Commented Oct 6, 2022 at 14:29
  • 1
    $\begingroup$ @MikeBrockington Actually that is not possible for the geometry of the prints of the OP, they have quite thick walls. Vase mode or also known as spiralize mode has a continuously increasing Z height, so therefore it is not possible to have more than 1 wall/perimeter. $\endgroup$
    – 0scar
    Commented Oct 6, 2022 at 20:23

I had the same concern to make mechanical connections where we tolerate a distance of 0.1 mm and these so-called "sewing points" making it impossible. I started to compare between the preview before printing in the slicer and the part printed before.

The problem is recurrent along a vertical line and always repeats itself at the same point. So by looking to the layer settings, there is a junction between the outer and the first inter shell. This junction could be avoided by modifying the "shell print order" parameter.

Here is a video shows the difference abd before / after picture. The line remains visible but the points disappear completely. You can set the layer height to 1.2 mm for better results.


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