Re: [CAD_CAM_EDM_DRO] PIC DRO stupid question #2

>
> There may be a space limitation on this hypothetical kluge. I was
> wondering what happens if you used say 3 of the 360 line strips,
> mounted them
> side by side, each 1/3 of a division offset from the previous. I
> don't have
> the signaling worked out but could it not give you much finer
> resolution?

I really doubt this would work. The gratings would have to maintain a
phase
shift over the entire length of the encoder, to a small fraction of one
line pitch.
That would be VERY hard to do with glass scales, impossible with mylar
films.

> A
> crude but cheap and possibly effective solution for the lack of finer
> gratings?
>
> I know that some of the linear scales often get contaminated with
> oil etc.
> Do they not sell replacement grates for refurbishing? I have not had
> failure
> with mine but I would want to buy the gratings as repair parts.

Generally, the scales can be cleaned, if only oil has gotten in. Some
will handle some
water, too. But, abrasive grit will wipe out most of the optical
scales. Since the
main grating is the most expensive part, it is not very likely one would
replace the
scale, only. But, I'm sure Teledyne/Gurley and Heidenhain would sell
the spar and
scale as a unit, and you supply the remaining pieces from your old
unit. But, you'd
get no warranty that way. I suspect there are graveyards of old scales
in machine
rebuilder's shops, but they may be unwilling to let them go.

Jon