Re: [CAD_CAM_EDM_DRO] Re: Digitizers, Renishaw

>
>Good idea - a bit like the way a galvanometer works and multiplies up a

>small movement. But, again, the most difficult part of realising this
>practically will be preventing the probe from rotating - you would have to
>use gimbals to be sure.
>
>Ian
>--
>Ian W. Wright
>Sheffield UK
>www.iw63.freeserve.co.uk
>----- 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
>> >>
>> >>
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>> >> List Manager
>> >>
>> >>
>> >
>> >
>> >Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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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.
>>
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>> List Manager
>>
>>
>
>
>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

>
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>