This report examines the effects of uncertainties in temperature and coefficient of thermal expansion on the expanded uncertainty of length dimensional measurements made away from the international standard reference temperature of 20degrees C for artifact standards and workpieces of various materials. Specific cases examined deal with: (1) uncertainties of thermal-expansion coefficients associated with values given in engineering references, standard reference data, standard reference materials and direct measurements; and (2) uncertainties of part temperature measurements associated with realizing the International Temperature sale of 1990 (ITS-90) and determining part temperatures relative to ITS-90 with the principal types of thermometry and achievable levels of temperature control.
Citation: Journal of Research of the National Institute of Standards and Technology
Pub Type: Journals
dimensional measurement, dimensional tolerances, length metrology, measurement uncertainty, reference temperature, thermal expansion