Re: [CAD_CAM_EDM_DRO] Re: Looking for short ballscrew

----- Original Message -----
From: "Jon Elson" <jmelson@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Friday, December 01, 2000 4:08 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Looking for short ballscrew


>
>
> Greg Nuspel wrote:
>
> > What if you used a servo motor on the fine feed wheel input, but ran a
cable
> > to a clamp on the quill. This cable then runs over a drum attached to an
> > encoder. Now you have no backlash in your system.
>
> Yes, you still have backlash! The encoder (discounting vibration of
> the cable, nonlinearities in the wrap of cable on the drum, etc.) will
> read true position, but the motor will have to rapidly jump from one end
> of the considerable backlash to the other, causing a big bump every
> time it gets to the other side. It will just bash back and forth .050"
> all the time, knocking the quill up and down a few thousandths and then
> reversing. This kind of mechanism will be a terrible pain to make work
> at all.
>
> Jon
>
>
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