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Pros and Cons of Color Mapping for First Article Inspection

Posted by Mike Knicker on Sep 18, 2013 10:15:00 AM

color mapping

Color mapping is commonly used as a profile analysis tool in first article inspection primarily because it allows you to quickly visualize the differences between the scanned part and its nominal CAD model specifications. After an object is scanned, point cloud software highlights the differences using a color map. Each color represents a different degree of variation between the scanned part and the original design so that manufacturers are better able to understand what the part's actual condition is and refine and improve the corresponding manufacturing processes.

Color mapping is beneficial in many cases, but like any other technology, it does have some limitations. The key to effectively using color mapping for first article inspection is understanding these limitations and the applications for which it is best suited.

Color Mapping for First Article Inspection: Pros

Color mapping is employed because it provides several benefits, including:
  • Ease of use - Color mapping allows you to use 3D scanning to get a big picture sense of how well the part conforms in one easy-to-understand visual display. At a glance, you can see areas where the part does not conform to the design and by how much.

  • Flexibility - You have the freedom to control the color spectrum. If you want to see only the differences within a certain range of accuracy, you can adjust the display so that only those deviations are highlighted.

  • Visibility - Color mapping can be conveyed in a number of ways. This includes free viewing software, dynamic HTML files, and 3D-interactive PDF files that allow you to move the 3D analysis result within it. This means that you can view the color map from multiple angles to get the most complete picture of the deviations on the entire part.

Color Mapping for First Article Inspection: Cons

The advantages of color mapping are many, but there are also some potential disadvantages worth mentioning.
  • The dazzle effect - Undoubtedly, color mapping produces impressive results. However, a visually interesting result is not a certain indicator of measurement accuracy. Looks can be deceiving, and confirming accuracy is important, even when a colorful map seems to indicate good results.

  • Inadequate data - Although color mapping is an effective way to determine where deviations are, it alone does not give you the hard data you need for process control. Further quantitative processing is required.

  • Invalid analyses - 3D profile analyses are only valid when the specifications stipulate a profile callout. Inspections must still be performed in accordance with engineering requirements. In such cases, a 3D analysis serves only as a visual aid.

One perceived disadvantage of color mapping is that it is too subjective because you can't use it to compare across multiple parts. This is a myth. You can actually extract points for part comparison, turn off outside geometry, and take 2D sections. All these features allow you to objectively compare the deviations between multiple parts, allowing you to more effectively refine processes.

If you are interested in learning more about color mapping or any other dimensional inspection technology, work with the experts at Q-PLUS Labs or download our free guide to selecting the right dimensional inspection equipment.

Have you ever used color mapping for first article inspection? Tell us more about your experience in the comments section.


dimensional measurement assessment

Topics: first article inspection, 3D Scanning, color mapping