Vertical profiled wall goes wrong

[BSSArch 0]

CURA Version: 5.6.0

 

Dear Forum Members,

 

I am encountering an issue with printing vertical profiled walls using CURA Version 5.6.0. Previously, I didn't face any difficulties with this aspect of printing, as evidenced by the attached pictures. However, today I noticed that these walls are printing very sloppily. Upon inspecting the CURA model, I observed numerous starts (depicted as white dots) on these walls.

 

It's worth noting that the vertical profiling of the current model is identical to those successfully printed in the past, both models printed at 10%.

 

I am seeking advice on how to improve the print quality of these walls. Notably, the other components of the print are turning out fine.

 

Thank you in advance for any assistance you can provide.

schepens-de mey 3D print.stl

[Slashee_the_Cow 429]

If you could provide a Cura project file of your print (.3mf, in Cura go to File > Save Project) that would help a lot more than just having the model because it'll contain all your print settings.

 

Your problem here is that the wall sections are tiny. They're a single wall thick. Assuming I'm getting the scaling right; the file doesn't use mm for units so I just resized it to fit my bed (best case scenario). Basically, the print head makes a quick stop then moves to the next one. There's no way to do that cleanly, even if you have the best retraction settings in the world (although it might not retract over that short a distance anyway.

 

Here it is step by step:

1. Start of layer:
   
2. This little bit here is the first part of the layer it does, probably because it's closest to the Z seam (I'm just using the stock "standard quality" profile).
   
3. Print head zooms off and starts to print walls:
   
4. Now comes back and does outer walls.
   
   Notice how it's doing a tiny little hump at each section? That's as far as it can go out (and come back in) without going into an area so thin it would have to stop and move back into the centre, because Cura prints the outline as a single, uninterrupted line (where possible)
5. Finishes the outer wall, starts coming back for this bit:
   
6. Goes to the closest part along the route it was travelling and does that little bit:
   
7. From here I'm turning travel lines on. It travels to the next closest bit that needs to be done:
   
8. Prints that little bit:
   
9. Travels to the next closest part:
   
10. Prints that little bit:
    
11. And... repeat:
    
12. Your finished wall section:
    
    The bits which are more noticeable are probably the ends, not the starts, since they'll get pulled away from their position because they're not dry yet.

So how do we fix it? Go to Walls > Minimum Wall Line Width and set it to the lowest advisable setting, 60% of the nozzle diameter. 0.4mm nozzles are fairly common, that gives you a minimum width of 0.24mm (although whether that's enough depends on how big you're actually printing it):

Now instead of doing one thick wall where it can't go back, it does a thin wall out and then back in.

 

This still won't give you a perfect print: Especially if your printer has a Bowden extruder (you put the filament into a thing somewhere on the frame which has a tube leading to the print head). It'll hopefully be a lot better, but it'll be constantly changing the flow rate between what it takes for one fat wall (between the bits that go out) and thin walls (for the bits which go out) and there's no way the extruder is going to be able to keep up. It'll almost certainly lead to overextrusion or underextrusion (or a bit of both) in these sections.

 

Also FWIW, this isn't the problem but significant portions of your model don't have any surfaces with the normals facing outwards:

Some programs don't produce very good STL files, so it's probably not something you did. Blender has problems. SketchUp is notorious for producing files with these sorts of problems. But even CAD programs which should be able to produce the best output files possible still stuff up sometimes.

[BSSArch 0]

Thank you so much for your thorough response! It appears that adjusting the 'minimum wall line width' is going to be quite beneficial. I'll give this a try once the current print is finished.

 

While I acknowledge that the profiles are somewhat thin, we've successfully printed similar designs in the past, yielding results like the one with the 2 cents in the picture. We're using a bowden extruder (CR10S).

 

Upon investigation, I've discovered that the previous version of Cura (4.13) handled things differently. That version didn't feature the 'minimum wall line width' setting, and after slicing, there were no white dots on the walls, as shown in the attached screenshots.

 

Reducing the minimum wall line width eliminates most of these dots, with the exception of one, which i can't seem to get rid of.

 

I've attached the models in 3mf format for both 4.13 and 5.7.1. I fixed the STL 😉 

I'll give this a try.

 

Cura 4.13.3mf Cura 5.7.1.3mf

[Slashee_the_Cow 429]

The white bits indicate points where it starts extruding after a move - in this case that's the Z seam, where it starts printing each layer. It'll do a white dot for anywhere it starts extruding on outer walls because where it starts can be visible sometimes.

 

Playing around with the Z seam options in your print settings (often the easiest way to find which options hide the Z seam best) if I set Z Seam Alignment to Shortest and Seam Corner Preference to Hide Seam puts it away in this corner:

[Dustin 160]

1 hour ago, BSSArch said:

Upon investigation, I've discovered that the previous version of Cura (4.13) handled things differently. That version didn't feature the 'minimum wall line width' setting, and after slicing, there were no white dots on the walls, as shown in the attached screenshots.

 

That was a specific key new feature to UltiMaker Cura 5.
https://support.ultimaker.com/s/article/1667417421589