A long time ago in a galaxy far away, there was some experimenting with this idea. MakerBot even put a conveyor belt system on the cupcake. It was terrible, like almost everything about the cupcake printer. I don't think they ever got automated serial prints going. Just auto eject. Looks like you could get something similar with M23 and M24 if you know the name of the file you want to print next ahead of time. I don't see a way to just print whatever the next file on the SD card happens to be.
http://marlinfw.org/docs/gcode/M026.html
It may be that there are software solutions that would do this kind of thing for you. I think there are quite a few bot farm management solutions that are supposed to have a que system.
Bryan
Retire early, retire often. [
HalfLifeDad.com]