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Chapter 11: E. Specialized Inspection Equipment 103
Telescope
Light ray
Target
mirror
Vertical reference planes
at right angles
Bed ways
(a)
Transit
Targets
Telescope
Dock rails
Workpiece
Prism or
optical square
(c)
Indexing table
(b)
Transit
Part II.E.4
Telescope
Telescope
Optical polygon
Pool of
mercury
(d)
(e)
Laser generator
Laser beam
Centering detector
(f)
Figure 11.3 Optical tooling.
Reprinted with permission of the Society of Manufacturing Engineers, Manufacturing Processes and
Materials, 4th edition, copyright 2000.
transit or sight level set in this manner may be swiveled around a vertical axis
to generate a horizontal plane. Plumbing, shown in Figure 11.3e, consists of autocollimating
a telescope from the surface of a pool of mercury to establish a vertical
axis.
An advanced step in optical tooling is the use of the intense light beam of
a laser. A centering detector, shown in Figure 11.3f, has four photocells equally
spaced (top and bottom and on each side) around a point. Their output is measured
and becomes equalized within the device and is centered with the beam.
This provides a means to obtain alignment with a straight line. Squareness may be
established by passing a laser beam through an optical square.