Scott,
This is a pretty specialized field and requires a lot of special equipment and processes. I would imagine if you went to purchase a cnc tool grinder, that it might have a lot of the necessary functions built into the operation manual.
First off, you need to learn about helical milling processes. This is the gearing action required to make a form cutter cut a helical path in the tool blank, to form the flute of the cutter. Various helix angles are required for different cutters specifically for certain metals.
A lot of high quality tools are made now, ground from solid hardened material. This means a cnc tool grinder creates the tool from start to finish. The blank could be high speed steel or carbide. Perhaps even a carbide preform, which would be easier to grind than carbide that has been sintered (final bonding to convert it from a pressed powder to "real metal" ).
Then, you need to learn about clearance angles to make a tool cut properly. This information is available in manuals that come with milling cutter resharpeners.
Other cutters, called form-relieved cutters are used for various milling processes, like gear cutting, etc. These require special lathes that can repeatedly push the tool into the toolblank, while it is rotating, to "back off" (create cutting clearance) for each tooth of a multi-tooth, wheel type cutter.
Its a big field when it comes time to buy the machinery to do it all.
