I'm fairly new to Blender, but I'm wanting to get into doing a bit of 3D printing with it. In the pic below, I'm modelled a sprocket for use on an armoured vehicle.
After a few days experimenting I've managed to work my mesh into something that has minimal tris and n-gons. I've also run clean-up on it, and removed any loose geometry, merged any duplicates and have avoided any non-manifold edges.
So far, so good. I applied a subdivision surface modifier to smooth the curves, and after reinforcing the geometry with extra edge loops, it's exactly how I want it - crisp edges, smooth transitions and (almost) 100% quads. To my mind, this should be ready to print as it is.
But, out of interest, I enabled the Mesh 3D Print Toolbox addon to fault-find any issues. Note the highlighted parts in the picture - 0 Non-Manifold vertices found in 'select-by-type', 0 N-M vertices found in the tool, and the sub-div modifier active.
But when I run the option 'Make Manifold', my model deforms. I believe what is happening is it is removing the reinforcing edge loops required to make the edges crisp when the sub-div surf modifier is run.
So my question is - can I take Blender at face value when it says I don't have N-M vertices, and print the model with the edge loops and the sub-div modifier active (i.e, don't both with the add-on)? Or, am I to believe the 3D print tool, which is telling me there are no N-M vertices, but is deleting my edge loops as though they were problematic?
Apologies if this is a bit lengthy, any advice would be appreciated!
EDIT: Pic of deformed sprocket (After Non-Maninfold clean is applied):
Pic of Sprocket with remesh applied: