Question [cura 4.x] 0.4mm wall printing problem

flywork · November 1, 2022

0.4mm wall is printed repeatedly.
I want the 0.4mm wall to be printed only once.

Can I fix the problem by changing the settings?
Or is it a bug in the 4.x version?

Edited November 1, 2022 by flywork

GregValiant · November 1, 2022

I can't reproduce this with just the STL (I used Cura 4.13.1). I ended up with a true single wall print.

In Cura, load the model and set it up to slice and then use the "File | Save Project" command to create a 3mf file. Post the 3mf file here and someone will take a look.

EDIT: I have to take that back. The first slice I did was single wall. I made a couple of changes and the second pass showed up and now I can't get rid of it.

5.2.1 does it in a single pass.

Edited November 1, 2022 by GregValiant

flywork · November 2, 2022

I use version 4.6.1. The same symptom occurs even with version 4.13.1.
Can someone please share the 3mf file if it succeeds with single wall?

If so, should it be regarded as a bug in the 4.x version?

Is there any way to solve this problem?

Due to other issues I don't use the 5.x version.

04wall.3mf

Edited November 2, 2022 by flywork

GregValiant · November 2, 2022

When Cura slices this model it sees four surfaces. Outside of the outer ring, inside of the outer ring, outside of the inner ring, and inside of the inner ring. The 4.x versions of Cura were never good when a model had features that required an odd number of loops. What you see here is the first pass printing the surface facing outward, and then a second pass printing the surface facing inward, then the nozzle moves to the inner (smaller) ring and does the same thing. I think this is one of the reasons that the Arachne engine was developed. 5.2.1 will print this the way you want and you can have both versions of Cura installed at the same time.

In the 4.x versions you have to fool Cura and with this model, since the inner and outer rings are the same height you can do it by changing the model to a donut with a .2mm floor in the hole. That creates the situation where the surface facing outward is a few mm's away from the surface facing inwards. The slice only sees two surfaces instead of four. Cura is set up to print: Wall Line Count = 1, Top Layers = 0, Bottom Layers = 1, Infill Density = 0%.