3D printing for storage card shell?
With the experience I have with my 3d printer you can make (almost) everything you can draw with it.

0.6mm parts can be 3d printed but will not be very strong though.

For joining the 2 halves when they are so thin, I think the best solution is to glue them together. With the things I make for myself I mostly use small screws or small nuts and bolts but with 0.6mm parts I guess this wil not be possible.