Thin wall not in a straight line at corners

[Hibino 3]

Hi guys, I am using Cura 4.12.1 and trying to print few very small boxes in different sizes. Since the box wall is very thin in the STL model so I enabled "Print Thin Walls" in Cura and was hoping to have a 1 0.4mm wall for all the boxes. But after slicing into GCode I found all the thin walls are not in a straight line(as attached image, I tried use a different slicing software to make sure it is not model's problem).

 

I tried change a lots settings but none acturally affects the thin wall, does anyone knows which setting in Cura can have the thin wall print as exactly as the model? Thank you.

box.stl

Edited February 1, 2022 by Hibino

[nallath 1,124]

You might want to try Cura Arachne. It's much better at slicing features like that.

[GregValiant 1,412]

Hello,

This is from 4.13.1 with the line width at .399.  As you can see, it looks good and how we would expect it to slice.  I may be hampered here as this old laptop is in Compatibility Mode so it may be over-simplifying the view.

 

If you would load that model, set Cura up to slice, and use the "File | Save Project" command, and then post the 3mf file here then someone can take a look.  

 

BTW:  I loaded that model into MS 3D Builder (to check for errors - none found) and it opened at 10X the size it is when opened in Cura.  That was odd.  I understand it shows in Cura as you wanted I'm curious if it was designed in centimeters and Cura is assuming millimeters?

[GregValiant 1,412]

I got Cura 4.13.1 to replicate this.  Turn off "Print Thin Walls" and set the Line Width to .399 or set Horizontal Expansion to .001 and it should be good.

This is with Print Thin Walls turned on and Horizontal Expansion at 0.0.

Edited February 1, 2022 by GregValiant

[WisseEngineering 0]

What i used this weekend for such projects is called Vase Mode.

 

This uses the option: " Spiralize Outer Contour".

 

This way cura changes a box to a vase by only printing the outer wall in a continous line.

[Hibino 3]

11 hours ago, nallath said:

You might want to try Cura Arachne. It's much better at slicing features like that.

Yes, I installed the Arachne Engine and it loaded my 12.1 profile and sliced it correctly, even without the "Print Thin Walls" on it still sliced all the walls. How reliable is the Arachne Engine? Since it is still says "Beta" so I have ignored it for quite a while now, but I guess this will be a big reason switching to it.

 

9 hours ago, GregValiant said:

BTW:  I loaded that model into MS 3D Builder (to check for errors - none found) and it opened at 10X the size it is when opened in Cura.  That was odd.  I understand it shows in Cura as you wanted I'm curious if it was designed in centimeters and Cura is assuming millimeters?

Yes, when opening in MS 3D Builder, before hit the "Import Model" button on the right the "File's units" should be "mm", but it is default to "cm" in 3D builder, not sure why this happens.

 

8 hours ago, GregValiant said:

Turn off "Print Thin Walls" and set the Line Width to .399 or set Horizontal Expansion to .001 and it should be good.

Thank you, this solved the problem to keep wall line straight. I guess when this happens again I will need to find way to trick Cura think "Thin Wall" is a normal wall and avoid the "Print Thin Walls" setting.

 

 

6 hours ago, WisseEngineering said:

This uses the option: " Spiralize Outer Contour".

 

This way cura changes a box to a vase by only printing the outer wall in a continous line.

I've tried this setting but since the wall is so thin in the model, even the "Spiralize Outer Contour" won't slice the wall without "Print Thin Walls" is on, and if "Print Thin Walls" is on, the wall is not in a straight line.

 

 

[nallath 1,124]

12 hours ago, Hibino said:

How reliable is the Arachne Engine? Since it is still says "Beta" so I have ignored it for quite a while now, but I guess this will be a big reason switching to it.

More reliable than the previous two releases of the Arachne engine. But since it's such a massive change, I expect that there will be issues that we haven't found yet. That's also why we release so many beta's for the rework; We need people to stress test it. I understand that people might be a bit wary of using a beta release, but it's a bit of a catch 22; It only gets to stable if we have enough people testing it.

That being said, even though it does have some cases where it produces somewhat suboptimal results, in most cases it will be at least in the ballpark of what the current engine does. In quite a few cases it's better. I've heard from multiple people that they have completely switched over, even though it's still in beta.

[Hibino 3]

2 hours ago, nallath said:

More reliable than the previous two releases of the Arachne engine. But since it's such a massive change, I expect that there will be issues that we haven't found yet. That's also why we release so many beta's for the rework; We need people to stress test it. I understand that people might be a bit wary of using a beta release, but it's a bit of a catch 22; It only gets to stable if we have enough people testing it.

That being said, even though it does have some cases where it produces somewhat suboptimal results, in most cases it will be at least in the ballpark of what the current engine does. In quite a few cases it's better. I've heard from multiple people that they have completely switched over, even though it's still in beta.

Thank you, I'll switch to it from now and will report bugs if I found any.