I wonder if you could just 3D-print a mold and then pour the aluminum in as part of a 3d printer like this, rather than use a nozzle, and you'd get better quality/resolution.
There are downsides, too: printing is slow, and the build area is small, furniture parts not gonna fit there.
Right now it is in a bed of fine glass beads that the printer drags through as it goes, so this is kind of a similar approach. For one offs or prototypes this might be good, but when you print more than one of something than a mold likely makes more sense.
Sand is cheap, and should be easy to 3d print, even for one-offs.
They're very expensive for that reason. It's hard even for precision machining.
Injection molding processes I've seen have super-tight tolerances. Something like plaster or sandcasting do not.
Ceramic is cheap enough that this might be okay.
Removal would be a pain. Probably some chemical which melts ceramic but not metal. Perhaps something mechanical which relies on ceramic being brittle to break it up. Dunno.