Re: [CAD_CAM_EDM_DRO] Re: Lathe Encoders

A 400 line encoder in quadrature will give you a resolution of
about .000098425" per step or a lathe cross slide, about .0002"
resolution in diameter. This is is probably not a bad choice if
the controller you're going to use can generated steps fast enough.
That is of course you're going to use something like a Gecko 320.
I don't know what Jon's servo requires. If you want better than
.0002" on the dia. then go with more counts per rev. but keep in
mind the maximum speed you want. For the lathe's Z axis I'd
think I'd go with an encoder with about 1/2 the resolution of the
Y since there's a 2:1 reduction.

Have fun,
Drew

John Mesh wrote:

> Thanks, Jon & Drew
> Tonight I checked with a dial indicator & clocked out to .1574"
> or 4mm. Not as obvious as it seems because the screw is
> .8 mm threads (once I found my metric thread gauge) multiple start.
> I haven't had the nuts off it yet, but whatever they used works
> great, as I can't see any backlash at all on the indicator.
> Is a 400 line encoder enough,for the crosslide?
> The carriage will get twice the counts, I think you would want more
> on the crosslide. What about using 2 different counts, or is that
> a no-no? The only reason I can see why they mounted the encoders
> (resolvers) where they did is to save space as the crosslide servo
> already hangs out quite a ways. Just trying to get the best
> resolution, as these machines don't seem to have any wear on them
> at all...nice and tight.
>
> John Mesh

--
Drew Rogge
drew@...