I am currently building a cnc router/mill which will be similar to the c beam bigmouth. I have 1 or 2 operations that will require 5-6 inches of height on the Z axis. One of the operations requires milling a rectangular pocket in an aluminum billet that is about .75 " X 2.5 " X 1.25 " deep. I already have a couple Bosch Colt routers and a Dewalt 611 with 1/4 and 1/8 inch precision collets . One of my questions is will the dewalt 611 be adequate for milling an aluminum pocket or will I need to get a spindle with a VFD. What I really need to know is will I be able to get the correct spindle speed with one of the routers I already have. Just got into this hobby and my brain is experiencing info overload.
I'm still learning on this, so don't take what I say as gospel, but I'm pretty sure that the routers, even at their lowest rpm are generally too fast for aluminum. It's fine for wood and other softer materials, but the high speed and relatively low feed rates that we use on machines like this just end up grinding the aluminum more than cutting. As a result, you get chip weld, not the best surface finish, and shorter tool life (adding air blast or flood/mist coolant can help though). Going to a VFD based spindle isn't cheap though, but you have far greater control over the speed of the cutter and can dial in a better "recipe" for aluminum than you could with a router.
I 'm sure I will eventually get a VFD head.but the money tree needs to bloom before I can get one. And, I want to do considerable research before I make that plunge.
