A novel artifact for testing large coordinate measuring machines

We present a high-accuracy artifact useful for the evaluation of large CMMs. This artifact can be physically probed by the CMM in contrast to conventional techniques that use such purely optical methods as laser interferometers. The system can be used over large distances; for example, over 4 meters, with an uncertainty of less than one part per million. The artifact is relatively inexpensive, robust for use in reasonable industrial environments, and significantly reduces testing time over traditional step gauge measurements.