Toward a New Mathematical Definition of Datums in Standards to Support Advanced Manufacturing

Published

April 30, 2023

Author(s)

Craig M. Shakarji, Vijay Srinivasan

Abstract

Recent advances in the digitization of manufacturing have prompted ASME and ISO standards committees to reexamine the definition of datums. Any new definition of datums considered by the standards committees should cover all datum feature types used in design, and support both traditional metrological methods and new digital measurement techniques. This is a challenging task that requires some careful compromise. This paper describes and analyzes various alternatives considered by the standards committees. Among them is a new mathematical definition of datums based on constrained least-squares fitting. It seems to provide the best compromise and has the potential to support advanced manufacturing that is increasingly dependent on digital technologies.

Citation

Journal of Research of the National Institute of Standards and Technology

Volume

23

Issue

2

Pub Type

Journals

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DOI Link

Keywords

ASME, constrained least-squares, datum, datum plane, Gaussian associated feature, geometric dimensioning and tolerancing, geometric product specification, ISO, least-squares, standards

Citation

Shakarji, C. and Srinivasan, V. (2023), Toward a New Mathematical Definition of Datums in Standards to Support Advanced Manufacturing, Journal of Research of the National Institute of Standards and Technology, [online], https://doi.org/10.1115/1.4054304 (Accessed October 14, 2025)