Laser projection systems for manufacturing assembly have been available since the early 1990s. The first systems were used primarily for aligning materials during composite layup--replacing both Mylar and fiberglass layup templates. They were also sometimes used for parts alignment or placement verification on finished assemblies. For instance, a projected laser template would show the fabricator exactly where to mount a bracket, position a paint stencil, or drill a hole.

Essentially a glorified laser-light show, the concept has always been fairly straight-forward: A CAD model provides coordinates to the laser projection system, which then uses mirrors to precisely steer the laser and draw the template. Because the laser is scanned quickly, the lines in the projected image look solid.

Although early systems could reduce the time for some production operations by as much as 80 percent, they still required a certain amount of manual labor because the projected template had to first be aligned with known points on the work piece before it could be used. The standard approach in many earlier systems (and some existing systems) is to attach tooling balls or reflective targets to known points on the work piece. The operator then manually points the laser beam at each of these targets, getting the beam to within a few inches of the target. That is close enough that the projection system can then automatically scan the immediate area, detect the reflection from the target, and locate the target center. The operator does this for a half-dozen targets. Once the targets are acquired, the software has enough positional data to align the template to the work piece with a high degree of accuracy, typically about 0.015 in (0.38mm).

Although this method was much faster than other templating techniques, it was still clunky, and only the operator‘s eye determined how closely they had aligned a part to the template. Even the best trained eye can only get to within about 30 or 40 thousandths of an inch accuracy. Today, advancements in laser projection systems allow for hands-free, unassisted alignment. Along with faster and more accurate templating, this new technology also provides unique capabilities for part measurement, assembly verification, highlighting areas requiring rework, and reverse-engineering and fabrication.