Re: [CAD_CAM_EDM_DRO] Servos vs Steppers costs

Jon -

If he used a 2:1 belt reduction, does he acheive
an increase (X2?) in linear force at the cost of
some speed?

In trying to figure out the formula you used below,
would the circumference of the drum become the circumference
of the pully mounted on the lead screw?

Thanks

Mike

Jon Elson wrote:

> I can calculate some values based on the 420 Oz-In torque.
> Since it is direct drive, you can treat the 5 TPI screw as if it
> were a drum with string wrapped around it, with a circumference
> of .2", the radius is .2/(2 Pi) = .03183". So, the pull on the
> 'string' would be 420 Oz-In / .03183 In = 13195 Oz, or
> 825 Lbs of linear force on the table. I have a small Bridgeport
> mill, and I have a setup with about 1116 Lbs linear force at
> the peak current of the servo amps. So, your arrangement with
> those motors direct driving the screw may be a bit weak, if the
> 420 Oz-In rating is peak.
>
> Jon