Optical comparators are instruments that cast a magnified image of a part on a screen for comparing with a standard profile or scale. These are non contact devices/instruments that function by producing large or magnified images of gear parts and components. These instruments also display the image on a glass screen with the help of an illumination source, including lenses and mirrors with the sole objective of making 2-D measurements. They are popularly used to measure, gage, test, inspect gear parts for compliance with certain standards and meeting specifications.

Based on the kind of image projected or produced, these instruments can be catergorised into:

• Inverted: Inverted image optical comparators follow a general standard and are less advanced for gear testing. They have very simple image system that projects image inverted horizontally or vertically.
• Erect: Erect image optical comparator uses technologically advanced optical system. These instruments cast image in its natural orientation. The image appears in the same orientation as that of the gear part being, which is being measured or evaluated.

Optical comparators plays an important role in detecting burrs, scratches, indentations and incomplete processing of gears and gear parts, in addition to length and width measurements.

Applications

Some of the popular applications of optical comparator are:

• Research & Development laboratories
• Industrial Machinery
• Medical Applications
• Metrological Analysis