How would you go about calculating the potential IPM a system could have given a certain amount of torque/rpm from motors and at least knowing the weight of the carriage/cross slide you are pushing? You would have to factor in resistance from either the linear rails/blocks or the dovetail way I guess. Calculating resistance from a tool cutter would be kinda a unknown as well.

Lets say for example you have a 30 pound carriage that rides on a 3" wide ground dovetail way thats regularly oiled. Lets say a high quality ballscrew pushes the system (NSK, Hiwin etc). For now leave out resistance from cutting tools. Now for this application what could we expect from say a DMM tech 750w servo vs a 400w servo?