Sanghera - i havent tried it with my wood machine, but i know people have succesfully milled aluminum and steel with their MDF\wood mills. shallow cuts! start with a very small cut and do experiments with the manual mode. i would imagine anythign thicker than 1/4 or 3/8 is pushing your luck. With my machine, if i tried to cut 1/4" aluminum, it would take... 8 or 10 passes, and the accuracy would be pretty bad by the end. It may work on a better wood machine. Mine is pretty bad. I was just using it to learn, which i have.
You will probably get a more detailed first hand reply from someone who does this.
Another option with a wood mill is to make a foam or wax pattern to do an "investment" or "lost wax" casting. then you would need either a way to melt aluminum, or to take the pattern to a foundry. there is lots of info on DIY furnaces, inc,uding easy to follow directions.