Any guidance to produce rubber parts with a tridimensional printer ? If gets too complex, perhaps some hard silicone instead ? Or room temperature vulcanizing RTV ? Would ultraviolet curing be ineludible ? What rubberish materials cure with UV ?

Can 3D printers carve material out instead of pouring ? As to create a mold ? Is it just matter of putting a 'negative' image file to 'print' a mold ?

Any capable hobby machine that you know of in the market ? As to start from a rubber block ? Yes, too many questions... tackle as many as you want.

Flexible filaments are available, and you can make a mold if you program it properly. It would use a lot of material, and it might need to be a system where any scaffolding can be dissolved away, since you might not have easy access to some regions.