Re: DRO Encoders

On 10 Apr 00 at 2:00, CAD_CAM_EDM_DRO@egroups.com scribbled
furtively:

> Message: 14
> Date: Sun, 9 Apr 2000 19:16:21 +0100
> From: "james owens" <wotisname@...>
> Subject: Re: DRO Encoders
>
> This is food for thought. I had never considered using a rotary wheel and
> friction. Yes I agree that the problem would be keeping the grot off the track but
> it should be little trouble to enclose it all in an aluminium tube with sealed
> ends. The errors in the mechanism could be programmed out after checking against a
> known measure.

when reading the suggestion I thought of putting the wheel *under*
the table/s if possible. this will auto shield it from swarf if in
the right place. depends on the specific mill though.

certainly I think the cable drive type can easily be shielded from
swarf and even cutting fluid should not affect it much. have a look
at an old radio with a dial cord for tips on how to string the
things up with one end fixed and the other spring tensioned. if you
get the spring on the correct end and the correct tension, it will
never slip under normal encoder axle loads. one thing to be settled
though is the size and shape of the shaft. this will affect counts
per unit travel and also any possible slip conditions.....

--
Living in South Africa
Flying power Kites
Chasing 3'6" gauge steam trains
http://www.ru.ac.za/departments/iwr/staff/daf/