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

Published

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.
Proceedings Title
Proceedings of the ASME 2018 Manufacturing Science and Engineering Conference
Conference Dates
June 18-September 22, 2018
Conference Location
College Station, TX
Conference Title
ASME 2018 Manufacturing Science and Engineering Conference

Keywords

circle, constrained least-squares, curve fitting, cylinder, datum, geometric dimensioning and tolerancing, least-squares, line, optimization, plane, sphere, surface fitting

Citation

Shakarji, C. and Srinivasan, V. (2018), Toward a New Mathematical Definition of Datums in Standards to Support Advanced Manufacturing, Proceedings of the ASME 2018 Manufacturing Science and Engineering Conference, College Station, TX, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926718 (Accessed May 14, 2021)
Created December 20, 2018, Updated October 2, 2019