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Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!unisoft!hoptoad!wet!smiller
From: smiller@wet.UUCP (Gregory Shane Miller)
Newsgroups: sci.optics,sci.electronics,comp.robotics
Subject: Needed: Optical/laser distance measuring unit
Keywords: laser optical distance
Message-ID: <2615@wet.UUCP>
Date: 15 Jun 91 19:54:18 GMT
Followup-To: poster
Organization: Wetware Diversions, San Francisco
Lines: 34


I'm interested in getting sources for laser light based units which measure
distance.  I have two specific applications in mind:

       [1] We have a 3 AXIS CNC machine and would like to use a laser light
           beam to measure the distance from the head (Z axis) to the object
           being machined (in our case a piece of FR4 copper clad).

       [2] In the production of the CNC machines, I would like to have two
           of these units mounted at right angles to one another with their
           beams pointing at the CNC machine.  Then as part of the quality
           control, I could move the machine through a standard test, and
           then by using the light beams as a second measuring system, I could
           find and correct problems like:

              [a] stepper/servo motors missing steps.  This is really great
                  for stepper motors.
              [b] non-perpendicularity in the X,Y axis
              [c] if the X,Y axis is slightly bowed or "snakes".

I'm looking for a system in which can do accurate measurements down in the
.0000x range. Does such a laser/optical test system exist?  Is there an easier
method to accomplish the same thing?  Thank you for any replies.
(smiller@wet.UUCP).

BTW - this technique has a couple of pratical disadvantages when it comes
      to setup.  In [2], how should one position the laser beams at exact
      right angles (perhaps an interference test could be made).  Second,
      even if you could, how should one place the test object such that it
      is not rotated somewhat with respect to the laser beams?  Can enough
      of the laser beam even bounce off a CNC machine or FR4 copper clad
      and return to the optical measuring unit?
-- 
G. Shane Miller [ smiller@wet.UUCP (415) 453-4926 ]