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Precision Measurements and Parametric Models of Vertebral Endplates
Published on: September 17, 2019
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Toward a New Mathematical Definition of Datums in Standards to Support Advanced Manufacturing.
Craig M Shakarji1, Vijay Srinivasan2
1Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899.
Journal of Computing and Information Science in Engineering
|October 9, 2024
Summary
New manufacturing digitization requires updated definitions for datums (geometric reference points). A novel mathematical approach using constrained least-squares fitting offers a promising solution for both traditional and digital metrology in advanced manufacturing.
Area of Science:
- Manufacturing Engineering
- Metrology
- Standards Development
Background:
- Digitization in manufacturing necessitates reevaluation of fundamental concepts.
- Existing datum definitions may not fully support emerging digital measurement techniques.
Purpose of the Study:
- To analyze alternatives for defining datums in manufacturing standards.
- To propose a definition that accommodates diverse datum feature types and measurement methods.
Main Methods:
- Review and analysis of various datum definition alternatives considered by standards committees (ASME, ISO).
- Evaluation of a novel mathematical definition based on constrained least-squares fitting.
Main Results:
- Several alternatives were considered, each with trade-offs.
- Constrained least-squares fitting emerged as a strong candidate for a new mathematical datum definition.
Conclusions:
- A new mathematical definition for datums is proposed.
- This definition offers a balanced approach supporting both traditional and digital metrology.
- It is well-suited for advanced manufacturing environments increasingly reliant on digital technologies.
Keywords:
ASMEGD&T/tolerance modelingGaussian associated featureISOcomputational geometrycomputational metrologycomputer aided designconstrained least-squaresdatumdatum planegeometric dimensioning and tolerancinggeometric product specificationgeometrical dimensioning and tolerancingleast-squaresstandards
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