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Basics - Optical Comparator, Part 2: Fundamentals

January, 2021

Are you looking to learn the fundamentals of optical comparators including their capabilities, advantages when compared to other measurement practices, technical tips and next-generation functions? Our free metrology resource website offers key knowledge and information related to dimensional measurement instruments, environment requirements, selecting the right tool for the job, and various inspection processes.


1 Overview

An optical comparator, also commonly known as a profile projector or shadowgraph, is a type of measuring instrument that projects a part's shadow on a screen, and the dimensions of the part are measured against design standards. The part is placed on the stage, and a light is shined on the part from underneath. This causes the part's shadow, or profile, to be projected on the screen and inspectors manually inspect the outlines of the targets. The most technologically advanced versions utilize software that automatically analyzes the part image to report measurements.

2 Capabilities and Advantages

A primary feature of optical comparators is that they have two dimensional measurement capabilities (X and Y directions), unlike hand tools such as calipers, which are limited to measurement in only one direction at a time. Optical comparators are non-contact measurement tools that don't skew measurement of flexible parts or damage sensitive parts. During the inspection process, nothing but light touches the part, so the part doesn't have any potential to warp or change shape. Typically, companies can see cost benefits through optical comparator utilization. One way is that they can reduce inspection time with optical comparators by measuring faster than conventional handheld gaging.

3 Core Technology

Learn about the core technology that drives these tools, and the next-generation optical comparators using the principals of these tools in new ways to bring added-value to production and quality inspection.

Measurement Fundamentals is an informative site offering knowledge related to dimensional measurements in manufacturing, including optical comparator basics. Visit the site to learn more about the topics above and more!