2. INTRODUCTION OF AUTOCOLLIMATOR :-
A general discussion of autocollimators is found in the
book Engineering Optics by K. J. Habell and Arthur Cox,
published by Pitman (London), 1948 .
Autocollimator is an optical instrument used for the
measurement of small angular differences.
For small angular measurement , it provides a very
sensitive and accurate approach.
It is a non-contact measurement of the angles.
3.
4. oo’ = (2*θ)*(f)
where f = focal length ( distance between
source and lens )
Autocollimator responds only to reflector tilt ( theta) .
5. TYPES OF AUTOCOLLIMATOR :-
• Visual Autocollimators
• Digital Autocollimators
6. 1) VISUAL AUTOCOLLIMATOR :-
• Visual autocollimators measure the
angle of optically flat (1/4 wave or
better), reflective surfaces in arc
seconds by viewing a graduated
reticle through an eyepiece.
• The longer the focal length of the
visual autocollimator, the greater
the angular resolution and the
smaller the field of view.
7. 2) DIGITAL AUTOCOLLIMATOR :-
• Autocollimators are PC-based instruments which are
designed to operate in the lab as well as in a
machine shop environment.
• use an electronic photodetector to detect the
reflected beam.
• No external controller is required.
• Advantages:
1) High precision.
2) Real-Time measurements.
3) User – friendly interface.
4) Creating data reports and transferring in
other programes.
8. APPLICATONS :-
Measurement of straightness and flatness .
Precise angular indexing in conjuction with polygons .
Comparative measurement using master angles .
Assessment of squareness and parallelism of
components .
Measurement of small linear dimensions .
9.
10. ADVANTAGES :-
Measure the Straightness and Flatness .
Used for higher accuracy measurement .
To check squareness and parallelism.
Easy to setup and operate.
Used to align components.
Measuring small angles.
11. DISADVANTAGES :-
regular maintenance is required.
Difficulty in positioning and identification.
Time consuming.
Requires sample cutting and processing for tracing
by the detector.
