Uncertainty Procedure for NIST Surface Finish and Microform Calibration
Jun-Feng Song, Theodore V. Vorburger
An uncertainty procedure is used for reporting the NIST surface finish and microform calibration uncertainties. The combined standard uncertainty is a combination of the uncertainty from the geometric non-uniformity of the measured surface, and the uncertainty from the measuring system, which includes the uncertainties from the calibration and check standards, instruments, environment, measuring setup, and from the long-term variations. Theoretical and experimental methods for testing instrument repeatability and noise, stylus tip size, filter and non-linearity are described. The relationships between the combined standard uncertainty and the calibration traceability, control limit of check standards, and reproducibility are also discussed.