Laser scanners that digitize features of 3D objects generally have fallen into two categories. At the high end have been $200,000+ coordinate-measuring machines (CMMs) built on granite bases. Manually operated scanning heads served the entry-level market.

But, "CMMs are beyond the budget of many companies," says Martin Schuster, founder and chairman of Laser Design Inc., Minneapolis (www.laserdesign.com), a maker of 3D laser scanners. "And manual models can scan only small objects and with limited accuracy."

In response, LDI recently assembled a scanner line around gantries from Techno-Isel, New Hyde Park, N.Y. (www.techno-isel.com). The gantries provide a stable, rigid, and turnkey scanning platform that helps LDI build complete machines for about 50% less than existing models of comparable size.

Techno's use of heavy cast aluminum side plates support the X axis for increased stiffness. Bases contain THK, Schaumberg, Ill. (www.thk.com), ball-screw linear-motion slides. Antibacklash ball screws efficiently transmit power through rolling-ball contact between the nut and screw. The arrangement provides high rigidity and longer life than Acme screws and nuts that rely on sliding-friction contact for operation. The result: 0.004 in./ft positioning accuracy, 0.0004 in. resolution, and +/-0.0004 in. repeatability, all on a per-axis basis. That's about one-fifth as good as most CMMs when compared over the same metrics though more than accurate enough for jobs with less-stringent tolerances.