Re: [CAD_CAM_EDM_DRO] Re: Digitizers, Renishaw

----- Original Message -----
From: "Smoke" <Smoke@...>

> First you mask (black out) the end of the pick up unit with some sort of
> disk (or possibly a short length of "rod") glued in place. Put a VERY
TINY
> pinhole in the disk (rod) to allow light to come thru.
>
> Mount mirror on the end of the probe, with the probe free to move
angularly
> when it contacts a surface. With a small enough pinhole thru a thick
enough
> disk, the angular movement should be enough to block light return to the
> opto unit. The probe would need to be free enough to move yet be able to
> return to center position CONSISENTLY when the probe has been moved away
> from contact with the part. It might be necessary to increase the
movement
> of the mirror by mounting it on the end of a "multiplier arm" between the
> probe and the sensor rather than directly on the end of the probe.
>
> How much "adjusting" it would take remains to be seen.
>
> Smoke
>
>
> -----Original Message-----
> From: Ian Wright <Ian@...>
> To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
> Date: Thursday, January 11, 2001 5:12 PM
> Subject: Re: [CAD_CAM_EDM_DRO] Re: Digitizers, Renishaw
>
>
> >Hi Jon,
> >
> >The only way you could get a similar accuracy using an opto set-up would
be
> >to make the disk very wide relative to the length of the probe and put
tiny
> >shutters at its periphery between LED/opto sensors. This would probably
> work
> >but, you would have a big problem in preventing the disk rotating whilst
> >keeping the movement light enough.
> >
> >Ian
> >--
> >Ian W. Wright
> >Sheffield UK
> >www.iw63.freeserve.co.uk
> >----- Original Message -----
> >From: "Jon Elson" <jmelson@...>
> >To: <CAD_CAM_EDM_DRO@egroups.com>
> >Sent: 11 January 2001 19:56
> >Subject: Re: [CAD_CAM_EDM_DRO] Re: Digitizers, Renishaw
> >
> >
> >>
> >> Well, there's the rub. The Renishaw design causes an open
> >> circuit when the contact probe is moved .0002" in ANY
> >> direction. I can see how this will work with an electrical contact
> >> between two hard, rigid parts. I can also see how bad contact
> >> could occur, as you say.
> >>
> >> I don't see an easy way to make a low-force probe that will detect
> >> such tiny motion in any direction by optical means.
> >>
> >> Renishaw obviously solved this problem, and have been making
> >> these devices for many years.
> >>
> >> Jon
> >>
> >>
> >> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> >discussion of shop built systems, for CAD, CAM, EDM, and DRO.
> >>
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> >> List Manager
> >>
> >>
> >
> >
> >Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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> >
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> >
> >
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>
>
>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>
> Addresses:
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> Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
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> bill,
> List Manager
>
>