Line width half that expected  

Active Member

I am trying to print a fine part, carefully crafted with walls a tiny bit larger than twice the nozzle size. (Width 0.85mm, nozzle size 0.4mm)

Cura slices these (as expected) with two outer walls, one each side.

Prusa Slicer slices these with 2x External Perimeter AND 2x Perimeter i.e. 4 walls.

Can anyone explain why Prusa Slicer does this and how it actually prints with line-width half of the nozzle size?


This topic was modified 2 weeks ago by Protopia
Posted : 15/09/2020 6:23 pm
Active Member

I should add that this is how it appears in the Pruse Slicer preview window.

I have a feeling that it is actually printing only two perimeters for each wall rather than the 4 shown in the preview window.

Posted : 15/09/2020 6:32 pm
Illustrious Member

Have you tried toggling Print Settings->Layers and perimeters->Quality->Detect thin walls?

If you want to save your part & settings in a 3MF project file, zip it and attach it to a reply here, we can get a better look at your issue. Otherwise, it's tough to visualize what's going on from your description. Pics would be helpful as well.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 15/09/2020 10:46 pm
Active Member

Yes. I have Detect Thin Walls ticked.

I will try to attach photos tomorrow.

Posted : 15/09/2020 10:51 pm
Active Member

All images are of the same object sliced with nozzle-size = line-width = 0.4mm.

e.g. the vertical bars of the outside of the O are .85mm wide.


Here is the Cura slicing:

Here is the Prusa Slicer slicing:

And here is the gCode produced by Prusa Slicer, imported into Cura Preview so that we can see whether the gCode matches the Prusa Slicer Preview (which it does).

Looking at the actual print, the filament is (as you would hope) melted and fused together and difficult to determine precisely what was printed, but it looks like 2 or 3 lines  not 4, so I wonder whether Prusa Slicer is printing 4 lines, some of which are extruding zero filament.

Here is the gCode file (zipped) if that helps: HBR_logo_v3 prusa.gcode

Posted : 16/09/2020 7:59 am

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