Slicing problem - one layer of stringing

[Valkrider 1]

I have 2 cones that I need to print a large one and a small one. I have drawn both in FreeCad and they render fine.

 

I load them into Cura V4.8 and they load and slice fine.

 

With the large cone on layer 20 suddenly I get a single layer that goes across the whole of the cone and then the next layer above all is fine.

 

With the small cone I get exactly the same thing on layer 77.

 

Any suggestions as to what may be causing this issue?

[Smithy 1,141]

Without the STL files it is hard to say anything, so please upload it here.

[Valkrider 1]

These are the two files. Thanks for taking a look at them

cone3.stl cone-large.stl

[Smithy 1,141]

hmmm, Cura says the model is not watertight, but not sure if it is really the case. The small one slices normal, I see no problems in the preview. 

 

You can try to use https://service.netfabb.com/login.php to repair the STL, just in case there is very small defect in the file.

[Valkrider 1]

Thanks I will give it a try. FreeCad says it is fine. I saw the problem when I printed them and then checked the Cura preview and found the layers that were causing the issues in the preview

 

[Smithy 1,141]

Ok, I haven't seen something in the preview. Which layer height have you used? Maybe I can reproduce it.

[tinkergnome 926]

42 minutes ago, Valkrider said:

FreeCad says it is fine.

 

How are these objects made in FreeCAD?

It doesn't look good at all. Nothing more than a few thousand "flying" triangles that are not connected.

In addition: The wall is razor-sharp at the tip. Which kind of printer can build this...?

 

 

 

 

It should look like this:

 

 

cone3.b.stl

 

[Valkrider 1]

My layer height is 0.2mm.

 

The wall is not razor sharp at the tip it is flat with a wall thickness of 0.8mm and a hole in the top of 1.9mm.

[tinkergnome 926]

11 hours ago, Valkrider said:

The wall is not razor sharp at the tip it is flat with a wall thickness of 0.8mm and a hole in the top of 1.9mm.

 

This may be valid for the larger one.

There's a sharp edge on the tip of the smaller cone.

 

Anyway - both models are broken and therefore results of slicers are unpredictable.

If you don't have seen it yet - here is a comprehensive tutorial about preparing models with FreeCAD:

 

https://yorikvanhavre.gitbooks.io/a-freecad-manual/content/working_with_freecad/preparing_models_for_3d_printing.html

 

[Valkrider 1]

Can you explain what you mean by "both models are broken" please?

[Mari 36]

broken  =  not suitable for slicing...  so redesign or repair the designs to get the best result in slicing and printing!

[tinkergnome 926]

7 hours ago, Valkrider said:

Can you explain what you mean by "both models are broken" please?

 

I quote myself:

 

On 12/1/2020 at 9:21 PM, tinkergnome said:

Nothing more than a few thousand "flying" triangles that are not connected.

 

That's the opposite of a manifold geometry.

You can load the stl files in Meshmixer (e.g.- like i did above) and it will show all mesh errors in different colors.

 

Why is a manifold mesh important?

https://www.sculpteo.com/en/3d-learning-hub/create-3d-file/fix-non-manifold-geometry/#Part-3

[Valkrider 1]

Quote

You can load the stl files in Meshmixer (e.g.- like i did above) and it will show all mesh errors in different colors.

I did this and didn't get the same result as you. All I ended up with was one red sphere

[fritzi 1]

Vielen Dank

ich habe im IN eine neue Variante gefunden, welche die neuen .stl dateien abschliesst!

Bei meiner "SCHATZKiste" klappt es 1x bei 9 Versuchen!! Aber ich habe ja zeit 🙂

Vielen Dank für die Unterstützung!

Bleibt schön gesund 

und ein frohes und besinnliches Weihnachtsfest!!

fritzi