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our new Okuma 8050 with linear rails and medium inertia motors is over-powered and 500W would probably move it but most likely not at reasonable speeds.
I should have mentioned that my machine uses linear bearings everywhere. That does make it easy to move.
In fact, what was almost rather frightening was the time I stripped off the X axis ball nut and tilted the whole machine slightly. The carriage went flying at just a few degrees off horizontal. Serious oops moment there!

Speed - well, more power => more acceleration. Very true. But my machine is a 'hobby' machine: even though I do some production work (for sale), I am not dependant on it for a living. It is fast enough. A nice BT30 spindle, up to 3,500 RPM. It does a nice finish on Al and steel.

cheers
Roger

I've been manipulated into accepting the following concept, there is little difference from a machine for hobby use and a machine for commercial/production use, I should expect the same performance, repeatability, precision and power based on the platform size.

I would never build a wooden router or power one with a dremel or porter-cable wood router or a cheap water cooled china high speed ER20 spindle, if the spindle is not designed to be air cooled and used continuously and properly power rated such as actual output of 24,000RPM 3.0KW then the spindle is considered garbage just like those cheap china 24,000RPM water cooled spindle rated at 3.0KW, but are 220V/10A and really only outputs 1.43KW and for mills it better be an S1 rated 2.2KW (3HP) output (220V/12.75A) 100-10,000RPM asynchronous servo spindle motor driving a BT20 or R8 spindle or an S1 rated 3.0KW (4HP) output (220V/17.25A) 100-10,000RPM asynchronous servo spindle motor driving a BT30 spindle and these are considered my bare minimum power requirement if I expect to do some real work.

Yes I can make a machine that moves along with 100W DC servo motors but if I can't cut stainless at reasonable feeds because it stalls an axis then I've made a wrong choice in axis motion power and need to make a new choice immediately.


The cost of 220V AC servos with drivers is pretty cheap now, 750W motor and drivers can be had for about $300.00 new and 16in travel, 1/2in DIA 0.100in pitch ballscrews are about $150.00 and provide 300IPM rapids and 100IPM cut speeds so a small mill with sufficient power to cost steel and aluminum shouldn't be expensive but a 500W BLDC servo and driver should be doable for half the cost and still be within the axis motion power requirement.

If a 1in DIA 0.200in pitch ballscrew is employed then I would expect nothing less than 750W using a 2:1 reducer and still see 300IPM rapids and 150IPM cutting speeds without stalling an axis and yes, 300IPM rapids on 16in of axis travel looks fast, using 1.5KW motors and no gear reducer gives you 600IPM of rapids and 300IPM of cut speed without stalling and becomes mandatory when large mass comes into play like moving and stopping 400lbs tables.