Servo sizing for router - 1KW seems small to me?

[ewest]

I've been plugging away at my servo calculations here for 'Monster Router' and using the VisualSizer SureServo program that AutomationDirect has released, for my machine, I'm getting a figure that says that a 1KW servo is enough for my needs. Seems small to me, but then again, I just don't really know.

Here are the specs. Rotating nut, shaft weight and inertia can be pretty much ignored.

I'm putting worst-case scenario numbers in too. All of the table, screw and reduction figures are pretty accurately defined as well.

It's geared such that at about 1500 RPM, the gantry is rapiding at about 1000 IPM. The gantry weighs 500 lbs, and I'm calculating for 300 lbs of cutting force.
This is absurd, I know. I'm also calculating it to accelerate to 1000 IPM in 0.2 seconds. Yep. Moving 2.8 meters.

So I come up with this...

At this feed, The motor meets system requirements by 131% for speed, 106% for cutting torque, and 174% for acceleration / deceleration peak torque.

Does this sound silly for a 1KW motor? I'm willing to believe this if it sounds reasonable to anybody else, or is there no way a 1KW could pull these kinds of numbers?

The reason this is an issue for me at the moment is that I'd like to stick with 1KW because the amps offer 1/3 phase input. I currently have 3 phase in my shop, but I have no idea if I'll always be there, or what the availability will be where I go next. I'd rather not use a phase converter either, but supposedly there are good CNC rated rotary converters in the 11 KW range for about $1300 - Not peanuts, but not a ton of money either..... Less than a new servo for sure.

Any thoughts? Suggestions? I'm pretty sure I've punched in all my data correctly. What do you fellas think?

[Zumba]

Those SHS rails and blocks that you got can do a hell of a lot better than 1000 IPM. Also, 1000IPM in 0.2 seconds is only 0.22G. So ignoring friction, your drive mechanism will only need 100lbs of force for a split second.

For wood, cutting force will be around 10-50 lbs unless you get yourself a 10-20hp spindle. Based on this, that 1KW motor will not only be sufficient, but overkill. You can crank up the acceleration if you want to, and definitely crank up the speed.

[Zumba]

BTW, what kind of a spindle were you planning on using?

[ewest]

for the time being, I plan on using a ****ty porter-cable..... maybe after that I can drop the $7000+ on the auto changing colombo water cooled unit and finally have something to hook my chiller up to aside from a radiator standing in for my air conditioner. I think it cost that much anyway, for either a 5 or a 7 hp spindle. Not sure, I'd have to go back and look at the quote. It was probably for the 5 HP.

Anyway, I was thinking of using the 2KW on the longest axis, but it really looks like I'm not going to need it, plus as I get in to heavier materials, I probably can't feed them that fast anyway, plus, most of the high feed rate cuts will be in light stuff like foam, so cutting forces are next to nothing anyway.

Again, though, the 2KW only adds another $500 to my servo budget, which I'd like to have around $5000. BUT, I'm thinking it's not worth it. Plus it weighs about 30 lbs more than the 1KW.

Andy