ROUGHNESS EFFECT ON STABILITIES OF STANDARD WEIGHTS CLASS E

Wirun Laopornpichayanuwat, Rungsiya Sukhon, Tosapon Pangviwate, Monchai Mitaree

Abstract

The stability of the mass of a weight is highly dependent on the surface structures of the weight. In this research, the data have been collected more than 10 years in order to study the trend in changing values of the conventional mass of the standard weight of 1 g to 1 kg class E1 and E2 by controlling the environment of the storage room for these standard weights. The resulting values are assessed to determine the relationship between the conventional mass when it is changing by time. The mean height of roughness profile (<i>Ra</i>) and maximum height of roughness profile (<i>Rz</i>) are determined at the begin and the end of this experiment. Which at the beginning of the experiment, the two values are within specification of OIML R 111-1. These two values are measured by applying a Mirau interferometer (MI) is composed of interference microscope with mirau objectives and light emitting diodes (LEDs) that provide white light over several µm and a vertical scanning interferometry (VSI). At the same time, the uncertainty values are reported. The drifting trend of the conventional mass value over time is quite constant when the values of <i>Ra</i> and <i>Rz</i> are within the specification of OIML R 111-1. Whereas, the drifting trend of conventional mass value is moving up or moving down when the roughness of the surface is out of specification.

Keywords

mass standard, roughness, Mirau interferometer (MI) and Vertical scanning interferometry (VSI)

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IMEKO TC

TC3 - Measurement of Force, Mass, Torque, and Gravity

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