In HSM setting, that is :) . Not talking about 5 ton production CNC machines that move
20lb/minAs I wuz making some dies, I needed to remove 2" long, 1/4" deep rectangular profile from a 5/8 x 3/8 (on narrow side) O1.
Conventional milling proved to be too much, removing .040 per pas, feeding in X or Y. The mill (X2, X3 ordered :) simply doesn't have power or rigidity required to handle deeper cuts. Plus O1 can work-harden on you in no time.
However, doing the same job by drilling out series of sequential , "holes", followed by light cleaning passes did the job in no time. The fact one can lock the table in X/Y eliminates all of the play. Of course, one has to use Z-stop of some sort (either quill or head, in my case), to control the depth of the plunge.
Endmill has to be centercutting and with metals that can work-harden on you, nothing beats carbide endmills