Certified Machinist - How long would it take me?

How long would it take me to become a certified machinist. I have a degree in Mathematics, Engineering Physics, and Chemistry. I have been in the investment casting business for a few years and have worked as a metallurgy engineer and have extensive knowledge of hundreds of alloys. I am able to read blueprints, draw in AutoCAD, and can write computer programs in C++ and Visual Basic. All I am wanting is a certificate or whatever they give out to be able to program my machines to machine the castings I make. How long would it take me to get this certificate and what is the best way to do it?