My $.02.
while the tool tech reps will give you great starting info, every component in the machine system will affect how fast you can go, and also what your surface finish requirement it as well.
Your endmill, the holder, the condition of your spindle, how rigid you are clamped, how much backlash is in the machine, don't forget to make concessions for the lunar cycle as well. This all has a bearing on how fast you will be able to go, well everything except for the Lunar cycle anyway. The other thing that will control how fast you are able to go even if the machine has the HSM option, is how the code is being generated. If your cut tolerance is too fine, the amount of code coming through the controll may choke off the machines movement and leave dwell makes in the part.
So as you can see there are 1,000,001 things that will impact exactly how fast you can machine this part! Maybe 1,000,002 things if you include the Lunar Cycle!!
"It's only funny until some one get's hurt, and then it's just hilarious!!" Mike Patton - Faith No More Ricochet