The design the buster beagle uses is an aluminum box you drop your molds into after printing them. Though this idea is interesting, I think, for people who are

The design the buster beagle uses is an aluminum box you drop your molds into after printing them. Though this idea is interesting, I think, for people who are injecting with variable size molds that a single casing would not suffice for. A desktop CNC at that scale to make simple stuff like casing boxes is probably going to be more affordable and less hassle/mess than your suggested setup pretty quick though. Desktop is definitely not going to be good enough to make aluminum molds themselves though. I think you need a 5 axis CNC for that. Surprisingly my makerspace actually has one of those and I considered learning how to use it but decided against it. In practice however on these molding setups I’ve found you are already kind of constrained on your mold sizes a lot simply by virtue of your machine’s volume capacity. The one I have goes up to 3 cubic inches, but in practice you can’t use all of that capacity and you get weird/bad results for too small of capacity too so the actual ranges of shot volume I can produce in a mold are actually constrained to something like 1-2.5 cubic inches