Re: [CAD_CAM_EDM_DRO] Re: Encoders / Slides

Jerry Kimberlin wrote:

>Jon Elson wrote:
>
>
>
>>scale has stripes on a 12 uM pitch, that would give .000118" per quadrature
>>count. That is probably good for CNC motion control. I don't know where
>>the x 10 fits in here.
>>
>>
>>
>I thought he meant that he has 3 scales, say x-y-z, and they have 10 uM
>pitch etched lines on them. But that doesn't change your comments at all.
>
>

But, it does. 10 uM resolution is .0004", a much larger unit. It is an old
rule of thumb that the encoder should have 10 X the resolution of the
display
and programming unit. So, this means that you shouldn't expect movement
in units less than about .1 mm with these scales. That will be fine for a
wood router, but it is a bit iffy for a CNC machine tool. It will probably
work, but the smoothness and accuracy may suffer a bit.

Jon