the idea is to take this keyfob that is an STL file
Organization for the Advancement of Space Industrialization and Settlement keyfob by garethjpowell - Thingiverse

and change it to G-code or a file I can use on a desktop CNC mill

I would like to flip it over and make a mold to make waxes for lost wax casting ,
the mold would be in MDF or aluminum , and the parts about 6 inches long

I do not have any software now but hoped to use free or open source to keep the costs down ,

the sample is just an idea , but gives an idea of what needs to be done ,

Thanks for your ideas