Challenges to NIST in Dimensional Metrology: The Impact of Tightening Tolerances in the U.S. Discrete-Part Manufacturing Industry

摘要

The report looks at recent changes in dimensional tolerances in a number of U.S. discrete-parts manufacturing industries and the measurement challenges to the National Institute of Standards and Technology (NIST) they pose. The changes in tolerances have been shown to be part of a long-term trend by which tolerances have been decreasing at the rate of approximately a factor of three every ten years. The report has also shown that whether by the twice-applied Gage-Makers factor-of-ten or Military-Standard factor-of-four relationship of measurement accuracy to manufacturing tolerances, NIST needs to be more accurate than these moving-target tolerances by factors of sixteen to one hundred. Since NIST does not have the current capability to adequately address such needs, it needs to develop new laboratory-based capability in each of the three tolerance regimes: the normal-tolerance regime of metal-cutting machine tools and coordinate measuring machines, the precision-tolerance regime of diamond slicing and advanced interferometers, and the ultraprecision-tolerance regime of scanning tunneling lithography and microscopy.