GM has gone to a laser scanner for digitizing clay models. The portable unit from Minolta contrasts with GM's traditional 4,500-lb CMM.
"We've been able to use the Minolta Vivid scanner on every part of the car from fender, grille, taillight and interiors," says Michael First, a design engineer at GM. In some cases, clay models are built of several components to check fit and interference. Changes are made directly to the models by adding or subtracting clay. Once a model is approved, Vivid scans the parts. The scans then get converted to numerical files describing the final part dimensions.
"We have found that in some cases you get a better sense of how components interface when you have a physical model like clay," says First, "So we haven't removed ourselves entirely from the physical world."
The Minolta unit uses safe, Class 1 laser-stripe triangulation to capture surface geometry and color-texture data. It captures objects in about 0.6 sec using either 200 X 200 or 400 X 400 range points. It can capture surfaces as small as 2.3 X 2.3 in. or as large as 43.3 X 43.3 in. in a single scan. Larger objects are scanned in sections, then merged.