Servos for new machine

[307startup]

Ok...so here I am in the third place I have found myself so far looking for help...here goes...

I am looking for a complete bundle...servos for all three axes with integrated encoders, drivers, controller...gear-reductions if at all possible...

I am looking for...fast rapids...fast feeds...zero-location loss...

I prefer an American made product.

I don't want a "kit" that I have to assemble myself...rather an integrated system.

Cost is not really a factor...don't want to mortgage the house, but I'd rather have quality, reliability and performance for my application.

This is a scratch-built design...a "mini-mill" using a cast polymer concrete base, bed and head.

I will be using a Gilman spindle...CAT40 taper...and would like my working area to be 24" x 48"

The idea is to build my own high-performance machine for my own use and see if it is marketable. If not, no loss, as I will be more than satisfied with it's abilities.

Thanks for any input...

Trent

[307startup]

One more thing...I would prefer a list of pros and cons for:

DC servos

AC servos

gear-reductions

[NC Cams]

Gear ratio: purely a function of how fast you want to move versus how much power and speed you can afford in a motor.

If you are willing to do the math, you can figure it out. Otherwise, find something close and then copy it.

2:1 was a common ratio that Bridgeport used on their servo equipped mills (IE: V2XT and/or Eztrak) which had 3000 to 4000 rpm DC motors with 26 lb-in torque ratings.

DC vs AC: DIY cost issues will probably limit you to DC. AC motors often require commutation feedback which adds cost and complexity to the project. Pretty sure you also have to carefully match the servo motor to the amp for proper functioning.

Try the following for more info on servos:

Servo motor control basics - brushed and brushless
http://www.a-m-c.com/download/docume...l/engnotes.pdf

http://www.cnczone.com/forums/showthread.php?t=26544

Servo vs Stepper:
http://www.cnczone.com/forums/showthread.php?t=17419

[Al_The_Man]

Originally Posted by WYLD One more thing...I would prefer a list of pros and cons for: DC servos AC servos gear-reductions

In between there is BLDC which is Brushless DC, which can be configured, mix and match drives, almost as easily as DC Brushed and has some of the advantages of AC Sinusoidal etc.
Gearing allows the economic sizing of motors and drives, which to a great degree is governed by your top expected rapid/feed rate, i.e. if you have a servo which is rated up to 6000rpm the you can generally afford quite a bit of reduction as without the reduction, you may never come close to using the max rpm of the motor, one principle sizing issue is inertia ratio between motor and load, and this is determined by your accel/decel rate( target inertia ratio <10:1).
One advantage is that reduction gearing reduces the inertia ratio by the square of the reduction.
I would suggest downloading one of the free sizing programs from any servo manufacturer like Kollmorgen etc.
Al.

[307startup]

Thank you very much NC Cams and Al the Man! I appreciate the help, I know it probably sounds dumb asking a question like that, but I'd rather sound dumb and get smart than sound smart and still be dumb! Any place I can look for some formulas? I'm sure that I can handle the math as long as I look for the information from the manufacturers and follow the formula...one always hopes at least.