Teams often ask whether structured light (white light) 3D scanning replaces a CMM. In practice it does not. The two methods answer different questions, and the right inspection plan usually combines them.
What structured light scanning is for
Structured light projects known patterns onto a part and reconstructs a dense point cloud or mesh. It is well suited to:
- Complex freeform surfaces (blades, housings, organic geometry)
- Full-field deviation maps versus CAD
- Fast coverage when a few hundred CMM hits cannot describe the shape
- Downstream reverse engineering, where you need the whole surface, not a sparse grid
See our metrology and inspection service for how we scope scan-based FAI and colormap work.
What CMM still does better
Contact CMM remains the right tool for tight-tolerance prismatic features, datums that must be defensible, and correlation of critical dimensions. When a drawing calls out a bore, a true position, or a small set of GD&T features with a hard number, we probe those features rather than inferring them from a mesh alone.
A typical combined plan
- Align and scan for coverage.
- Build a deviation map against CAD or a master.
- CMM-correlate the features that carry the risk.
That is standard operating practice at Bolton Works for regulated and high-value hardware. If you are choosing a method for a Connecticut or Northeast program, send photos and the drawing and we will recommend scan, CMM, CT, or a mix.
— Bolton Works