Re: [CAD_CAM_EDM_DRO] Re: Bridgeport Boss 6 Stepper Motors

vavaroutsos wrote:

> Jon, these motors are 400W continuous. The peak rating is about
> 1200W. They have a max RPM of 4500, but torque falls off at this
> speed.
>
> Maybe I should use a higher gear ratio like 4:1 as I shouldn't need
> full torque for rapids. This would give 225 IPM rapids with a 5 TPI
> ball screw and would give about 1200 lbs of continuous thrust with a
> peak thrust of about 3600 lbs. This sounds like it should be more
> than enough.

Yup, enough to break stuff when you aren't careful - just like I did!

> Why do you think Bridgeport used such large motors? Are they geared
> for really fast rapids?

They may be, but I think they felt they needed a LOT of acceleration, so
corners didn't get rounded off. This may be a bit of idiot-proofing the
machine, ie. it is easier to give it lots of acceleration than to explain
to machinists why it can't make a perfect 90 degree corner at 250 IPM.

Jon