There different types of cnc machines based on the axises they can machine on. Some can only do flat cuts and holes and such in metal while some can make complete parts from a block of aluminum. You also have cnc laser cutters, water jets, etc.
It's absolutely not worth it at all. It would costs hundreds of dollars and you wouldn't see much of a strength increase. You'd also be wasting so much material and time, it's just stupid.