Autores: Marcella Rocha, Davi Quintã

Abstract: Abstract. Mass is one of the basic quantities of the International System of Units (SI), its measurement is essential for several fields. The Mass Laboratory (Lamas) of the National Institute of Metrology, Quality and Technology (Inmetro), is responsible in Brazil for providing traceability of mass, through the National Kilogram Prototype (K66) which has direct traceability to the International Kilogram Prototype (IPK) which is related to Planck’s constant after redefinition of the kilogram. Mass traceability is given through documented unbroken chain of standard weights and balances calibrations. Calibration of balances is one of Lamas’ activities that provides traceability to other areas such as chemical metrology, biotechnology and other mechanical quantities. Analytical balances have an adjustment procedure that ideally restores the factory settings, but over time and continued use, the analytical balances may be not adjusted and significantly influence the instruments indications. This work aims to determine how long an analytical balance remains adjusted through the results of calibrations over time. From the calibrations, the normalized errors have been calculated and it has been concluded that the adjustment modifies the balance errors of indication and that the balance is out of adjustment in less than a week.

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