Bumps/blips on Cog surface in Cura and prints

[shaun_n 1]

Hi everyone, 

I am having trouble with these bumps appearing during the slicing of my part. And whilst not a perfect replica, the bumps appear on the print as well. 

First photo shows the slice preview, and the 3D-printed result. This is an issue as this cog needs to mesh with a reciprocal part, and the bumps stop it from happening. 

I was fortunate enough to find an old UFP file where I had 9 of these cogs laid out, and you can see no bumps are present. This printed perfectly and got me out of a pickle, but I am keen to figure out the problem, as it shouldn't be happening. 

The second pic shows the UFP file with the correct slicing. 

I have also attached the STL and the old (working) UFP file if that helps.

I think this is an issue with the slicing as the problem is present there, and also the print.  

Printer: Ultimaker 2+ Connect

Filament: Ultimaker Tough PLA

0.15mm layers

Speed: 40.0mm/s

Enable retraction ticked

Cura V5.3.0

I have even gone back and installed older versions of Cura to see if that was the issue but unfortunately not. 

This has got me stumped, and I would be grateful for help solving this. 

 

Thanks, 

Shaun

Roller 2P-Inner_24.05.stl 2+_9 inner rollers.ufp

[shaun_n 1]

I resolved the issue with the assistance of Ultimaker support team. 

There is an option in the print settings to turn off the feature "Print thin walls". This solved the issue for me and hope it helps anyone in future.