cura 5.1.1 weird dividing of first layer

[printnewb 2]

 

the first layer is divided in two parts while it should be a single homogeneous layer.

I have made sure the model is a solid without open edges and the line that should not be there should only appear 2 layers later.

 

Other sliceers, including the cura clone crealty slicer do not have this 'feature' out of the box.

 

Is there a setting I can change to have cure not already print lines a few layers in advance?

 

 

please find attached my cura project file and stl.

 

For reference a screenshot of the model

 

CE5P_magnet holder quarter with walls.3mf magnet holder quarter with walls.stl

Edited January 15, 2023 by printnewb

[printnewb 2]

I tried disabling support as it could have been a support artifact for that wall that starts 2 layers later.
But since the model is a solid (100% infill) there is no need for support there.

 

But that did not do the trick 😞

 

I have added some extra stiffners that also should be solid. Also those get visible on the first layer.

Please see a section view.

 

and this is the first layer in cura

 

this leads to less efficient print times and increases the failure rate of the first and subsequent layers.

 

Layer 1 and 2 ( the first 0.9mm) should be homogeneous. So the print head never should have to stop and make sharp corners or anything.

 

Layer 3 should have these shapes on it visible now on layer 1 and 2.

 

I can force cura to not print these shapes the first few layers by increasing the distance between the bottom of the model and the lowest top layer. But that makes the solid too high in the lower parts.

Edited January 15, 2023 by printnewb
added some extra info

[GregValiant 1,251]

This is X-Ray view in Cura.  You can see that there is a problem surface within the model.

 

I didn't notice anything odd when I sliced it though.  I was able to repair the model with MS 3D Builder.

Is it supposed to look like this?  I think the "dividing the first layer" may be because that outboard part is so thin.  It's only a couple of layers thick and then the wall starts.  I think Cura is preparing for the wall support.

Edited January 15, 2023 by GregValiant

[printnewb 2]

Yes thank you, the model looks good in your cura. There was no need to repair the STL though. That red part you repaired was a start of the stiffeners I was in the process of adding but forgot to remove just before deciding to post here.

 

The new project I have attached has the stiffeners finished so no errors in the model. But the same issue is now more pronounced as can be seen in the images in my previous post.

 

I also had this theory regarding support but disabling support did not do the trick for me 😞

 

Anything else I can try?

 

 

CE5P_magnet holder quarter with walls.3mf

Edited January 15, 2023 by printnewb

[printnewb 2]

problem solved.

 

I had to set the top and bottom layer thickness to 0. now it is exactly slicing like I have the model.

[GregValiant 1,251]

Scale the model to 250% in the Z.  Set the model on the build plate and slice it.  Look at layer 1.  I think you will see that there is no divider until Cura prepares for that wall.

This is layer 2 with the model at Z=64.75 tall.  No divider.  On Layer 3 the divider shows up.