If you were in my situation, how would you get the piece of plexiglass to be one with the 3d printed circle?
Take forever and do a terrible job of sanding down the plexi? Use the zero tools I have that are appropriate to cut the plexi down?
Cut the model in studio and add a negative to slot the plexi into, then add a pause, insert the plexi, and print the rest over it, permanently installing it? Make a ledge in the model for it to sit on somehow?
If sanding it down so it fits in the bore tightly is an acceptable solution, why don’t you just print the ring so it’s slightly bigger and the plexiglass disc fits tightly instead of not at all like in your picture?
Reprinting the ring might take a bit longer, but it’d be a lot less work.
Otherwise, I’d split the ring horizontally and add a notch to both halves that is 1/2 the thickness of the disc (well, just slightly bigger than that to allow for tolerances). Print them both, fit together, the disc will guarantee alignment of the two halves. Run a bead of glue or solvent around the outside seam to lock it all together.
It works for magnets and other insertions. The only issue you must deal with is the likely lack of bonding on the plexiglass.
Some tests will help you with that.
Snap-in basic
You could create something with a tolerance (as already mentioned) that allows the plexiglass to be force-pressed into the base. I would consider having an inner top ring that you push over the top of the plexiglass though, this would give you the same thickness ring above and below the plexiglass.
Snap-in notches
You could instead create a base the plexiglass would snap into by having ridges around the inner top. You then push the plexiglass down into the top with the ridges causing friction until an area of the thickness of the plexiglass is met and it will be stuck under those ridges.
There is no perfect solution. Tests are your friend.
