Inner thread displayed correctly but sliced as block

[LukasAV 0]

Hi,

I created a model with an inner thread using FreeCAD, exported as an .stl. The thread is displayed correctly in FreeCAD and Blender and also in Cura. However, after slicing, Cura wants to print the section with inner thread as a complete block. I tried different settings, turning support on and off, but always got the same result.

 

Using Cura 4.2.1 on Linux Mint 18.1 Cinnamon 64-bit.

 

Thanks for any help.

test2.stl bottom-demo.FCStd.zip test2.3mf

[gr5 2,172]

This is common with certain cad software.  Did you use sketchup?  What cad software did you use?

 

[gr5 2,172]

 I have tons of advice but I need to know what software you used.

 

Here's a tiny piece of advice, look at it in xray mode - first make sure you are in "preview" mode (at the top center) and then on the upper left switch from "layer view" to "xray view".  If you see any red colors then that is the problem.  Shades of blue and white are good.

[LukasAV 0]

Thank you very much for your help.

I am sorry I did not state clearly enough I also created the model in FreeCAD, thats why I attached my FreeCAD project file (had to zip it so I could upload it).

I viewed the model in x-ray mode and the flat peaks of the thread are indeed red, so I suppose this is an error from FreeCAD when creating or exporting the thread.

[burtoogle 513]

If you have the mesh tools plugin installed then you will see this diagnostic when you load the model. Basically, it's saying that there are gaps in the model and it cannot be sliced correctly.

 

[ahoeben 1,948]

The threads are not connected (as shown here in MeshMixer for visibility):

 

It is sort of impressive that you managed to do that in FreeCAD; normally it exports solid models without disconnected faces.

[LukasAV 0]

It seems like a previous part of the model was not correctly attached which broke all steps afterwards.

See FreeCAD forum

Thanks for all your help!