Re: [CAD_CAM_EDM_DRO] Re: Scanning with Touch Probe

I'm not real familiar with the application, but would a ceramic stereo
phonograph cartridge work?
Bob B.

----- Original Message -----
From: Ian Wright <Ian@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Sunday, April 23, 2000 2:56 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Scanning with Touch Probe


> Or perhaps we could arrange a probe to have a ball part way down as a
> universal bearing and for its upper end to move around a glass disk
with
> fine concentric lines within a double quadrature head - two heads at
right
> angles. Jeez, isn't that difficult to describe concisely! What I'm
really
> trying to suggest is a system similar to a normal encoder system
linked to a
> lightly sprung probe. The position of the 'ball bearing' (which may be
> better as gimbals) would allow for magnification of the movement and
so the
> reading. Thinking about it more, it may be possible or preferable to
use two
> short strips of regular encoder at right angles and allow for their
vertical
> displacement from one another (which will affect the readings shown)
in
> software. I have no idea how you would sort out the software but I'm
sure
> something could be done along the lines of 'detect the first change in
> position of the probe, stop the machine, wait a fraction of a second
for
> things to settle, read the two quadrature scales and work out the
probe tip
> position.' This is probably way off the mark and the job can probably
be
> done much easier with a couple of capacitative or inductive sensors
(voice
> coils like in a CDRom laser head?) but I thought it may stimulate
> conversation. Anyone have any other ideas?
>
> Ian
>
> --
> Ian W. Wright
> Sheffield UK
>
>
> ----- Original Message -----
> From: Track Burner <Creative_Player@...>
> > Although I haven't taken the time to figure it out yet, it seems
like this
> > system moved until the probe touched the surface of the object, then
> > stopped, then separately measured the amount of travel of the spring
> loaded
> > fiber touch point.
> > That way your system has some time to coast to a stop after each
fast
> move,
> > without being afraid of crashing the probe or loosing accuracy from
> > mechanical overshoot.
> > An inductive, LVDT like probe for short travel would be fairly easy
to
> > construct and calibrate I would think.
> > Maybe this is an idea?
>
>
>
> ----------------------------------------------------------------------
--
> Your high school sweetheart-where is he now? With 4.4 million alumni
> already registered at Classmates.com, there's a good chance you'll
> find her here. Visit your online high school class reunion at:
> http://click.egroups.com/1/3139/2/_/423600/_/956517091/
> ----------------------------------------------------------------------
--
>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
>
> Addresses:
> Post message: CAD_CAM_EDM_DRO@egroups.com
> Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@egroups.com
> List owner: CAD_CAM_EDM_DRO-owner@egroups.com, wanliker@...
> Moderator: jmelson@... [Moderator]
> URL to this page: http://www.egroups.com/group/CAD_CAM_EDM_DRO
> FAQ: http://www.ktmarketing.com/faq.html
> bill,
> List Manager
>