Slice Help, Weird Geometry on my Flat Surface

[Bucks1226 1]

Hello,

I recently got a 3-d printer and have been trying to print this mold for some fishing baits. I designed them myself in Fusion 360, but when I take the design to the Cura Slicer, it adds or subtracts weird geometry, like triangles and rectangles where there should be a flat surface and flat out ignores other parts of my design, like the air vents on the right sides of both pieces of the mold. I have tried messing with the mesh settings, but cannot figure it out. I have also attached pictures on how it should look, and then how the slicer is conceiving it. The pictures on the prepare tab are how it should look. I included a zoomed in picture as well to highlight the small air vents I have in there that go horizontally across the whole mold. The picture on the preview tab is how Cura is slicing it. I have also included the layer before it does the weird geometry and then the layer that adds it.  I would appreciate any ideas on how to fix this. Thanks!

 

Edited July 26, 2022 by Bucks1226

[GregValiant 1,145]

With the models loaded in Cura and ready to slice, use the "File | Save Project" command and then post the 3mf file here.

It almost looks like the mating surfaces of the models aren't flat.  That would have been hard to do in Fusion, but something is going on.

I would suggest that you get rid of the locating pins as they are too easy to break off.  Instead, put mating holes in that piece and glue in short pieces of wood dowels as the pins.

[Bucks1226 1]

On 7/26/2022 at 9:48 AM, GregValiant said:

With the models loaded in Cura and ready to slice, use the "File | Save Project" command and then post the 3mf file here.

It almost looks like the mating surfaces of the models aren't flat.  That would have been hard to do in Fusion, but something is going on.

I would suggest that you get rid of the locating pins as they are too easy to break off.  Instead, put mating holes in that piece and glue in short pieces of wood dowels as the pins.

Thank you for your advice. I was messing with it for awhile and it actually appeared that while using circular holes for the air vents, the slicer was not getting the mesh correct up to a certain radius of the holes which was .35 mm. I changed the air vents to squares and everything worked fine after that. Thank you again for weighing in on my problem, I really appreciate it. 

[GregValiant 1,145]

I printed a hole chart once.  I was looking at the effect of "Hole Horizontal Expansion" and one of the side issues that because apparent was that vertical holes under about 1.2mm diameter don't want to print with a .4 nozzle.  The molten plastic gets dragged into the center of the hole before it can cool and become solid.

On a horizontal round hole you were too close to being only 1 layer thick (depending on where the Cura slice went through) and so I can see where getting rid of the radius would help.

"I changed the air vents to squares."  Good job figuring that out.  Ya gotta love a good workaround.