Skirt Bug?

[Jonas_2603 1]

I have tried to slice the following model from thingiverse: https://www.thingiverse.com/thing:4706119. When slicing the model with one of my custom settings, the skirt arround the model started to overlap with the printed parts of the initial layer. I then tried to slice the model with one of the standard Cura profiles which sloved the problem. But i could reproduce the same overlapping by changing the "Hole Horizontal Expansion" from 0mm to 0.25mm and the "Initial Layer Height" to a value between 0.15mm and 0.22mm. Outside of this range the problem didnt occur (while having the worst overlapping at arround 0.19mm like seen in the picture).

 

Any idea on whats causing this problem?

[KingOli 0]

I have the same problem with various settings. The skirt sits partly under the model. This began with 4.12 for me. I was using 4.8 before and never had this.

 

 

Edited December 30, 2021 by KingOli

[gr5 2,269]

Sounds like a bug.  It would be good if you guys could post this as an "issue" on github.  Unfortunately you need a github account but it's easy and free. Then post the issue here:

https://github.com/Ultimaker/Cura/issues

 

Also include the project file (which contains the STL, and all your settings) that reproduces the issue.  The developers are very busy and if they can't reproduce your issue the first time they are likely to move onto another issue.  To get the project file do "file" "save project file".  Also it's best if you verify that the problem is in the latest copy as they might not know if it is something that was fixed in the latest cura.

 

[KingOli 0]

Thanks gr5, I have opened issue #11174.

 

 

[ahoeben 2,012]

It looks like the model does not have a flat bottom, and/or it is not 100% flush to the bed. You can get a better skirt by pushing the model into the bed by a tiny amount (ie: setting the z to -0.1 or so).

[gr5 2,269]

Oh.  I'm embarrassed.  This is not a bug.  I should have had @KingOli post the project file here for me to look at before suggesting cura issues.

 

The part that the skirt goes "under" is not touching the build plate. If you want the part to touch the build plate then the 4 portions that are over the skirt need to start at the same height as the rectangular portion that they are attached to.

Or as @ahoeben says, you can set Z to a slightly negative value but to do that you have to first go into the cura preferences menu "preferences" "configure cura" select "general" and uncheck "automatically drop models to the build plate".