Deviation mapping (sometimes called colormap inspection) compares a scan to a CAD model or to a scanned reference. Each point gets a signed distance. Color shows the story: typical palettes run from blue (low / short) through green (in tolerance) to red (high / long).
Why color maps change the conversation
A table of twenty CMM points can pass while a pocket wall is banana-shaped. A colormap makes that obvious in one view. Engineering, quality, and the supplier can look at the same picture and argue about process, not about who picked the hits.
Common uses in our lab:
- Dimensional checks of freeform and machined surfaces
- Wear versus a new-part scan or CAD
- Coating or plating build-up
- Shrink and warp on molded or cast parts
- “What-if” alignments when the datum scheme is in dispute
Alignment is the method
The map is only as honest as the alignment. We document how the scan was fitted to CAD — best-fit, datum, RPS, or a constrained scheme — because a different fit can move a red zone. Dense data lets us try more than one alignment without putting the part back on the machine.
Read more on deviation mapping in our metrology practice, or send a part photo if you need a map for a release or a failure review.
— Bolton Works