Re: interface board

Gar Willis wrote:

> From: garfield@... (Gar Willis)
>
> On Sun, 09 May 1999 23:56:22 -0500, Jon Elson <jmelson@...>
> wrote:
>
> >actually, you can make the whole works yourself, if you can get the
> >grating.
>
> Yeah, but honestly, I don't have time nor patience to be making sensors
> and adapting optics. Fine if it's my avocation, but it's not. I DO
> appreciate the rundown on the basic simplicity of 'quad' via optics, but
> I wanna make parts, not develop sensors and so-forth. It's just sad that
> HP doesn't see the value of a 250 X 4 sensor array. If they did, then US
> Digital would make the optics post-haste, and it'd be a done deal.

Well, I really don't think it would be that big of a project. But, knowing that,
I went with precision ballscrews and relatively cheap shaft encoders. You
can get a much greater resolution that way. A leadscrew with .200" lead
(5 TPI) and a 1000 line encoder (counting all transitions for 4000 counts/rev)
gives resolution of .00005" per count. If you can get a .100" lead screw
(I have one for the Z (quill) axis) you get .000025" per count - that's 25
micro inches. Great for EDM feed.

Jon