Accessible Unlicensed Requires Authentication Published by De Gruyter May 26, 2013

Uncertainty Estimation of Coating Thickness Measurement Results

Abschätzung der Unsicherheit in Ergebnissen aus der Schichtdickenmessung
Biserka Runje, Gorana Baršić and Željko Alar
From the journal Materials Testing

Abstract

This contribution presents an estimation of the measurement uncertainty of coating thickness measurement results. The measurements were performed on a steel sheet sample with an outside shell plating. The sample is protected against corrosion with two layers of 100 ¼m thick dry film. In the present case, the criteria of “80-20” have been applied. The measurement uncertainty evaluation has been carried out using Monte Carlo simulations (MCS method) in accordance with the document OIML G 1-101 Edition 2008 (E) Evaluation of Measurement Data – Supplement 1 to the Guide to the Expression of Uncertainty in Measurement – Propagation of Distributions Using a Monte Carlo Method. The criteria “80-20” was evaluated based on the mean coating thickness measurement results, as well as, on the basis of the complete measuring information. Aside from the expected value, complete measuring information comprises the value of measurement uncertainty. In the case where measurement result is described only as the mean of the measurement values a wrong conclusion regarding the fulfillment “80-20” is reached.

Kurzfassung

Der vorliegende Beitrag stellt eine Abschätzung der Messunsicherheit bei der Schichtdickenmessung dar. Die Messungen wurden an der Außenhaut eines Stahlbleches vorgenommen. Das werkstück war mit zwei trockenen 100 ¼m dicken Schichten gegen Korrosion geschützt. Für die Untersuchungen wurden die Kriterien “80-20” angewendet. Die Messunsicherheit wurde mittels der Monte Carlo Simulation (MCS Methode) in Übereinstimmung mit dem Dokument OIML G 1-101 – Edition 2008: (E) Evaluation of Measurement Data – Supplement 1 to the Guide to the Expression of Uncertainty in Measurement – Propagation of Distributions durchgeführt. Das Kriterium “80-20” wurde basierend auf den durchschnittlichen Ergebnissen der Schichtdickenmessung evaluiert, sowie auf der Basis der gesamten Informationen aus den Messungen. Neben dem erwarteten Wert beinhaltet eine vollständige Information über eine Messung auch den Wert der Messunsicherheit. In den Fällen, in denen Messergebnisse nur auf der Basis der Durchschnittswerte beschrieben werden, ergibt sich eine falsche Schlussfolgerung hinsichtlich der Erfüllung des “80-20” Kriteriums.


Biserka Runje, born in 1962, graduated at the Faculty of Mechanical Engineering and Naval Architecture (FSB) of the University of Zagreb in 1986. Since 1987 she has been working at the Laboratory for Precise Measurement of Length, Department of Quality and Control of the FSB. She acquired the Masters degree in 1997 at the FSB, University of Zagreb, and the Doctor‧s degree in 2002. Since 2005 she works as an assistant professor. The scientific work includes research in the field of metrology of surface roughness and research in the field of nano-metrology as well as in the field of quality management.

Gorana Baršić, born in 1977, graduated at the Faculty of Mechanical Engineering and Naval Architecture in 2001, enrolling in the same year in the postgraduate study. In 2001 she was elected assistant at the Faculty of Mechanical Engineering and Naval Architecture, Department of Metrology and Control. Her scientific work includes research in the fields of surface roughness measurements and nano-metrology.

Željko Alar, born in 1966, graduated at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb (FSB), in 1993. At the beginning of 1994 he started working at the FSB as junior assistant at the Department of Materials. In 2001 he acquired the Master‧s degree at the FSB and the Doctor‧s degree in 2008. The scientific work includes research in the field of measurement and control of thin metal coatings.


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Published Online: 2013-05-26
Published in Print: 2010-03-01

© 2010, Carl Hanser Verlag, München