speed and feed again

[ltmquik]

I think that the general rule of thumb should be use what works best for the application. With aluminum and high end CNC qualified endmills, the spindle speed will generally become the limiting factor. For high production, run it till it breaks and back off. If you don't do it the guy on the next shift will.

[Paul_S]

When you find a feed and speed that works well. Note your chip load per flute. Width and depth of cut. Cubic inch remove rate. As well as your feed per tooth.

SFPM = RPM x tool dia / 3.82
(3.82 = 12/pi)
IPT = IPM / RPM / number of flutes
CIPM = IPM x width of cut x depth of cut
chip load = IPT x sqr(width of cut / tool dia)

You want to keep your chip load constant.
IPM = number of flutes x chip load x sqr(tool dia / width of cut) x RPM

Once you know a chip load that works for given material and tool. Find the "index" value. index value = chip load / tool dia.

Then for any size tool a new chip load for that size tool can be estimated.
Chip load = index x tool dia.
IPM = number of flutes x chip load x sqr(tool dia / width of cut) x RPM