John Bennett is the only person who posted something reasonable. Metals sheers, grinders, CNC machine, plasma cutter. All of those either leave terrible edges, or deformed metal. Except the cnc, but unless your carving the case out of a solid block of aluminium, its not the right tool either
There are multiple machines out there but a cnc machine is basically a 3d printer for metal. Instead of producing the material to make the shape it cuts away