Re: plastic strips for encoders

They chose mylar because of its temperature stability.
I have used them for about a year now and have seen no problem with them.
Dan
-----Original Message-----
From: Elliot Burke <elliot@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Sunday, May 30, 1999 1:49 PM
Subject: [CAD_CAM_EDM_DRO] plastic strips for encoders

>From: "Elliot Burke" <elliot@...>
>
>Many people have written about using the US Digital plastic strips for
>encoders.
>Has anyone calculated the thermal effects of the plastic?
>The CTE of plastics is so much larger than other engineering materials that
>even a few degrees F over a foot will make a very inaccurate measurement.
>When I get to my office I'll look up the exact numbers, but they are
>freightening.
>If the strip was glued to a piece of glass it would work better, but might
>not fit in the reader.
>If the encoders use transmissive optic a metal backing wouldn't work.
>
>Elliot Burke
>HighTide Instruments
>
>
>
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