ORIGINAL: wyowindworks
Cutting foam is cheaper than cutting aluminum simply because it can be cut much faster. The less time that the blank is on the CNC table the cheaper it will be.
True, and the material is much less expensive. It is so easy to work that it could just as easily be carved by hand. Factor in how much work it is to build the computer model needed to program the CNC, I would carve it by hand if using foam. Aluminum is the most economical for production tooling for producing hundreds, or thousands of parts. As a hobbiest, it would be prohibitively expensive, unless you have money oozing out of your pores.