HP 5501A Operating And Service Manual page 17

1.2 Section
I,
General Information
In addition to explaining what the System Manual covers, Section I also covers the following
subjects:
a. How to use the other manuals supplied with your system.
b. An overall system level discussion of what a laser system is and how it makes
measurements.
c. Types and examples of typical measurements made with the Laser Transducer System.
d. An explanation of the available system configurations and what i s contained in each
system. By first determining what type of system you are going to use it will be easier
to selectively read those sections of the manual that apply directly to your problems.
In summary, Section I contains the information you will need to familiarize yourself with the
Laser Transducer System, and the support documentation and equipment.
1.3 Section II, Laser Transducer and Optics
This section provides the background information on the physical layout of the Laser Trans-
ducer head and receiver, and the optics necessary to direct the laser beam between them. It is
very important that you know and understand the material contained in this section prior to
mounting these units. The material is covered as follows:
An overall discussion of what constitutes a basic measurement system. This includes
only the optical portion of the Laser Transducer System. For information on the system
electronics refer to Section I 1 I.
Measurement components. Detailed descriptions of the individual measurement com-
ponents of the Laser Transducer System including dimensions, mounting, and instal-
lation information. Also discussed are the allowable measurement configurations for
the optical components including interferometers, beam benders, and beam splitters.
Accuracy considerations. Deals with factors affecting the ultimate measuring accu-
racy of the Laser Transducer System. Centers on the effect of the environment under
which the measurement i s made along with techniques for compensating for these
effects. Specific types of measurement errors including the effect of thermal expan-
sion of the part being measured or cut are discussed. Consideration is also given to
cosine error or errors due to misalignment.
System installation. Discussion of how to install the measurement components in
actual measurement applications. Consideration of possible combinations to split and
direct the laser beam to the measurement location. Also discussed is how to route the
laser beam to the measurement location with emphasis on minimizing possible mea-
surement errors. This will include the effect of Abbe errors and thermal instabilities
on the measurement process. Techniques of protecting the beam from disruptions
such a s thermal effects, cutting fluid, and chips which could interrupt the measure-
mentare also discussed.
Alignment procedure. General rules for the actual alignment of the Laser Transducer
System after it is installed on a machine are discussed. Different techniques of align-
ing the components, depending upon the installation and accuracy requirements are
also covered. Specific examples include a 3-axis measurement application utilizing
the linear interferometer and an X-Y stage application using plane mirror interfero-
meters. Each example illustrates fundamental techniques which can be applied to
most installations.