Subscription required for access to full text. License restrictions may limit access.
Summary:
Technical standards are increasingly moving toward a requirement to understand and account for uncertainties in measurement.The need to quantify uncertainty, and to express it together with the measurement result, has been a focus for international standards for some time.In practice, this has led to a great deal of difficulty in some applications as to how uncertainty is assessed and how much uncertainty there really is from any part of the apparatus and process.Simultaneously, the competitive nature of business is driving a need for tighter manufacturing tolerances in order to improve technical performance or efficiencies.The consequences of errors in measurement are potentially more severe, and there is an associated need to measure with greater accuracy.New technologies can accommodate this need in many circumstances, but for a wide cross section of established businesses, it may not be financially viable to reinvent the process, and refining measurement accuracy is a preferable approach.Mathematical analysis can quantify uncertainty but does not always address how it may be improved.Understanding potential sources of error, and as importantly their relative contribution, can be essential to addressing the need to improve both reliability and reproducibility of results.The objective of this paper is to separate and examine individual sources of error in a number of typical measurements.We will focus on measurements of real microstructural features using optical microscopy and digital imaging.Areas examined will include metallographic preparation, microscope components and settings, camera selection and settings, software considerations, and some human factors.For each potential source of error, the relative contribution to total error will be assessed.Where possible, specific recommendations for best practice will be outlined.
Dates of Publication and/or Sequential Designation:
Also available online via the World Wide Web. Tables of contents and abstracts freely available; full-text articles available by subscription. Full text article also available for purchase. Also available in PDF edition.
Reproduction Note:
Electronic reproduction. W. Conshohocken, Pa. : ASTM International, 2019. Mode of access: World Wide Web. System requirements: Web browser. Access may be restricted to users at subscribing institutions.
