Lads, please, what the bloody hell is it. Explain it to me like I'm 5.
Is it CAD attached to a lathe?
Nope thats cad cam, and even then the cad prog has to write a prog for the lathe as there are a few different cnc programming systems/languages. some using codes and some using 'conversational' languages.
That's what I USED to do btw.
3d printing is producing a 3d figure part from a drawing using stereo lithography or laser sintering, I got a job years ago at a place based in Liverpool Uni that made 3d prototypes, and exact replicas for museums, they were gonna teach me how to use all of the latest technology for it at the time (and no doubt keeping up with the tech), my 1st job was to be making an exact 1:1 replica of the oldest gaelic cross in Ireland as the weather was starting to deteriorate the original.
A lot of funding was pulled though and they couldn't afford to take me on, in fact the place ended up closing down due to funding issues from the museums.
Look up stereo lithography on youtube.
Basically 2 lasers projects through a liquid and where they meet the liquid solidifies, and a part can be built up in 'layers.' laser sintering does it in basically a cloud of dust.
Nowadays 3d printers can use a variety of materials to produce finished parts as opposed to prototypes made just of a plastic resin.
Very complex parts can be produced without the need for any 'machining' or assembly