Metrological Traceability of Dimensional Measurements to the SI Unit of Length (An ASME Technical Report)

The purpose of this report is to provide guidelines for demonstrating the traceability of dimensional measurements to the SI unit of length (the meter). The International Vocabulary of Basic and General Terms in Metrology (VIM) [7] provides a general definition of traceability. However, many details are not specified by this definition. This report provides an interpretation of the VIM definition. The demonstration of metrological traceability of a dimensional measurement per B89.7.5 requires the following: (a) clear statement of the measurand (the quantity under measurement), (b) identification of the measurement system and/or standards used in the measurement, (c) a statement of the measurement uncertainty for the measurement result, consistent with the principles described in the Guide to the Expression of Uncertainty in Measurement [1,2], (d) an uncertainty budget that describes and guantifies the significant uncertainty contributors, (e) documentation traceability of the length standard(s) used in the measurement back to an appropriate metrological terminus, (f) a measurement assurance program that assures that the measurement system (and other standards if used) and the conditions of the measurement are within the validity conditions of the measurement uncertainty statement.

Intended for design, drafting, mechanical, manufacturing, production, tool/gage, quality, process and project engineers, CAD/CAM/CAE specialists, inspectors and educators across a broad range of global manufacturing. Special emphasis on aerospace, automotive, medical device, precision instrumentation and related industries.

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