Height "discrepancy" or incorrect settings

[cgrejsen 0]

As a CAD exercise I created an exact copy of my wedding ring (22.9mm x 22.9mm x 6mm) and exported the STL file to Cura.

Cura reports the correct size, and slices without any errors or warnings, however printing does not yield the expected result. After three attempts with CAD changes focused on outer smoothness only, and printing at 0.1mm resolution I have three different rings of varying heights, 4mm, 4.2mm and 4.8mm. Diameter is consistent, so I assume it has something to do with the dizzying number of settings affecting layers. I am fighting the urge to just increase the height in small increments, and would really like to understand which settings affect this.  Any insight appreciated.

 

Edited December 28, 2018 by cgrejsen

[Smithy 942]

Can you save your Cura project and upload it here, then we have the model and all settings.

[cgrejsen 0]

Hi Smithy,

Thank you for checking this - project file enclosed.

 

-Christian

CE3_WeddingRing.3mf

[Smithy 942]

The walls at the bottom and the top are too thin for the printer (<0.4) and therefore some layers are missing. You can try to enable the setting "Print thin walls" in Cura (use the search field to find the setting) or maybe better design the ring to have at least 0.41mm walls.

[Smithy 942]

Another possibility is to decrease the line width to something smaller, but I guess you designed the ring to be very "sharp" at the bottom and the top.

[cgrejsen 0]

 

Thanks that makes sense and I really appreciate the input. I will increase the thickness of the wall and give it another whirl.

 

 

[Smithy 942]

I guess it was that sharp due to the way you designed the ring, but honestly, if the printer would print it so sharp you would cut your finger 🙂 

[cgrejsen 0]

Hi Smithy,

I tried the thin walls option, but did not notice a difference. To remove the thin edges, I scaled the height from 6 mm to 8mm, 9mm and 10 mm, removing the tops and bottoms, leaving just 6 mm in height with edges around 1 mm. Each print reached 5.5mm.

I noticed some asymmetry and it appears some of the lower layers are lost, so I printed using a raft, and the entire ring printed in full height, and with symmetry.  

-Christian

[Smithy 942]

Best is to design it next time to avoid the thin walls, then everything should be fine.

But I got a better result with the thin wall option. Before I got 50 layers and enabled I got 59 layers in total.