HP 5501A Operating And Service Manual page 70

Figure 2-47 shows the Y-axis retroreflector and the X-axis measurement optics. All of the
optics are mounted on a common bracket which
is
attached to the Y-axis. The laser beam re-
flected from the beam bender in Figure 2-40 enters the beam bender shown below the single
beam interferometer and
is
reflected vertically into the single beam interferometer. The mea-
surement beam is then reflected horizontally along the X-axis to a retroreflector attached to
the X-axis machine slide (not shown). Note the position of the X-axis receiver which is unique
to the single beam interferometer.
Figure 2-47. X-Axis 1 nstallation
2.33 MECHANICAL INSTALLATION CONSIDERATIONS
2.34 General
When determining how to install the Laser Transducer on a specific machine, a number of
factors must be considered in addition to the method of dividing the laser beam into the ap-
propriate number of measurement axis. Some of the more important points to consider are:
a. Selecting the measurement paths to minimize Abbe error.
b. Installing the interferometer and retroreflector to minimize deadpath errors.
c.
Avoiding extreme thermal gradients near the measurement path which could disrupt
the measurement or cause errors.
d. Providing protection for the laser beam where cutting fluid, chips, or air turbulance
could interfere with the measurement.
6
In many cases it may not be possible to completely eliminate these sources of error but every
'
effort should be made to minimize them. The following paragraphs discuss methods of in-
stal ling the Laser Transducer System that maximize accuracy and measurement reliability.