Hi MA, I think you might run into some problems with slicers considering your object to have areas of self-intersection because the cylinder and inner wall basically touch or graze very close to each other in these areas here:



It would probably be good to have a little bit of spacing here:



Basically when the slicer goes to slice your STL file in order to form proper regions the slices need to make well formed intersections with a plane which means the intersections result in closed loops. When 2 different surface areas are very closely pinched together it can make it hard to get a clean intersection result at those areas and that can potentially mess things up.

So for 3D printing, try to avoid making really thin sharp needle type things like this:



- Michael