Single Nozzle Width Wall Troubles

[dstnceswmer 0]

Been struggling for a while to get a good slice of a model that has an upper lip on it that I need to be as thin as possible (within reason). I modeled it in Fusion360 to have a uniform thickness of 0.4mm to equate to exactly one nozzle width when slicing. Using Cura v4.8 I am getting all sorts of strange behavior when it tries to slice this lip. At first with default settings (line width at 0.4) it tries to print the lip as a top/bottom surface indicated by the yellow lines in the preview as opposed to the red wall lines below the lip. Additionally it adds multiple tiny little infills in the corner which are quite awful for this small model.

 

(Raw Model)

 

 

 

 

Some things I've tried:

• Default settings

This is with "print Thin Walls" on, 0.4mm line width, 0.4mm thick lip walls modeled

("Default" Settings)

 

 

 

 

• Turning off "Print Thin Walls"

Interestingly this failed to slice the lip portion at all leading me to believe cura for some reason determined my 0.4mm thick wall is thinner than the 0.4mm nozzle width or 0.4mm line width which makes 0 sense.

(Thin Walls off, 0.4mm modeled wall thickness, 0.4mm line width)

 

 

 

 

 

• Various wall thickness in the model itself (0.45, 0.5, 0.6, 0.7)

With print thin walls off as the thickness increased, portions of the lip began slicing until reaching 0.7 where it seemed to do a full pass. However the dimension on the interior was larger than spec'd. (This was using "Print outer walls 1st btw). Additionally with the 0.7mm width walls the nozzle still seems to do a 2nd pass.

(Thin Walls Off, 0.6mm modeled wall thickness, 0.4mm line width)

 

(Thin Walls On, 0.6mm modeled wall thickness, 0.4mm line width)

 

(Thin Walls off, 0.7mm modeled wall thickness, 0.4mm line width)

 

 

 

 

 

• Lowering Line width

With "Print thin walls" on this stayed the yellow "surface" line color until getting down to around a line width of 0.12mm at which point it sliced 2 side by side (well overlapping actually I think) walls that looked really thin. I have not tried printing with this yet, though 0.12-0.1mm seems way too small to be setting my line width.

(Thin Walls off, 0.4mm modeled wall thickness, 0.1mm line width)

 

 

 

 

 

• Arachne engine Alpha release

This has seemed the most promising. All defaults were left as is (0.4mm line widths, Print thin walls, 0.4mm width model) and it sliced with the solid red "wall" lines in the preview all the way up. I'm guessing this has to do with the variable line width stuff built into this alpha release. Zooming in though I Noticed the Lip walls seem much thinner than all other lines in the preview. This is leading me to believe Cura is still not seeing my 0.4mm lip walls as actually being 0.4mm for whatever reason.

(Thin Walls On, 0.4mm modeled wall thickness, 0.4mm line width, Alpha slicing engine)

 

 

 

 

 

I really believe the root cause has something to do with Cura not recognizing my 0.4mm modeled lip as being a single line width wall, but have 0 idea why. Any advice on this would be appreciated, or maybe it is an actual bug I found, IDK. Happy to post any other relevant data files to help troubleshoot this as well.

 

Thanks,

-Justin D.

Micro DB-9 Casing V5.stl

Edited March 4, 2021 by dstnceswmer