Long-term stability evaluation and the reliability of the optical polygons calibration system from Inmetro

Abstract

4 f. : il.The Dimensional Metrology Laboratory (LAMED) from the National Institute of Metrology, Standardization and Industrial Quality (INMETRO), the brazilian National Metrology Institute (NMI), has, for many years, a system used for calibration of optical polygons and precision indexing tables. Its long-term stability is being evaluated since 1995 through periodic calibrations of a LEITZ 12-faces optical polygon. The metrological confidence of this system is shown by the comparison between the measurement results from INMETRO and from the Physikalisch-Technische Bundesanstalt (PTB), the german NMI, obtained with the calibration of the above mentioned optical polygon. The choise of this standard was due to its stable construction and the reflection quality of the measurement surfaces. The evidences of the calibration system stability and the results confidence of the INMETRO’s laboratory are shown in this paper