CAD software package

Hi,

What happens when you try to make money from you hobby. It is no longer a hobby but is now a job! That said, I need to find a CAD Package that will create machine readable files that can be read by a mill for manufacturing purpose. I see from some simple internet searches the are lots of packages available virtually free. So I guess the question is; How does one make sure thier work is useful to the manufacturer? Am I thinking about this properly?

Any information will be useful.

Regards,

Bob