Horizontal layer lines in lamp shade

Bambu Lab P Series Troubleshooting
1

Hi everyone,

I’ve been printing a lampshade in Spiral Vase Mode. I’ve tried a lot of different approaches, but I keep running into the same issue: horizontal lines on the surface.

What I’ve tried so far:

  • Different nozzles:
    • 0.4 mm nozzle with 0.8 line width → the lines actually get worse
    • 0.8 mm nozzle, fully calibrated → still visible lines and same as 0.4 nozzle and 0.8 with
    • 0.4 mm nozzle with 0.4 width and 0.24 layer height → this gave me the best results so far.
  • Tweaking settings: more/less cooling, higher/lower temperature, faster/slower print speed.
  • Making the model extremely high poly in Blender (up to 5 million faces) in the hope of getting smoother results.
  • I printed with pla and petg but same results.

The outcome:
The lampshade is smooth to the touch and structurally fine, but the horizontal lines and banding remain visible. It’s hard to capture clearly in photos, but in real life you can definitely see them, especially when the lamp is lit from the inside.

My question

  • Is this simply normal with FDM printing, especially with large smooth surfaces?
  • Or are there slicer tricks/settings that could help reduce this effect further?

20250915_181753
20250915_1817531868×4000 356 KB

Any advice is much appreciated!

Thnks and greets
Chris

2

You can try to reduce the layer height (to say, 0.12 instead of 0.2) to reduce the visibility of layer lines, but overall, thats about what to expect. From the photo you might have some very minor z bands, but on FDM in general, and bambu printers in specific, there’s no good golden bullet to address those. In general its from unreliable filament diameters, uneven layer construction times, physical wobbling, or all of those.

3

I do not think line width’s much larger than the nozzle diameter will work and the wiki says doing so will probably cause quality problems. See this wiki article
What is line width?

I’m winging it here but if you are trying to make the lampshade stronger, maybe use a large diameter nozzle but but change to a finer layer height. The below picture is of your options when using a .4mm nozzle but all the nozzles have a variety to choose from. In my experience, the smaller the number the better the surface but also can seriously increase the time it takes to print your model.

Line Height
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