SIST EN ISO 14253-2:2011
(Main)Geometrical product specifications (GPS) - Inspection by measurement of workpieces and measuring equipment - Part 2: Guidance for the estimation of uncertainty in GPS measurement, in calibration of measuring equipment and in product verification (ISO 14253-2:2011)
Geometrical product specifications (GPS) - Inspection by measurement of workpieces and measuring equipment - Part 2: Guidance for the estimation of uncertainty in GPS measurement, in calibration of measuring equipment and in product verification (ISO 14253-2:2011)
ISO 14253-2:2011 gives guidance on the implementation of the concept of the "Guide to the estimation of uncertainty in measurement" (in short GUM) to be applied in industry for the calibration of (measurement) standards and measuring equipment in the field of GPS and the measurement of workpiece GPS characteristics. The aim is to promote full information on how to achieve uncertainty statements and provide the basis for international comparison of measurement results and their uncertainties (relationship between purchaser and supplier).
ISO 14253-2:2011 is intended to support ISO 14253-1. Both parts are beneficial to all technical functions in a company in the interpretation of GPS specifications [i.e. tolerances of workpiece characteristics and values of maximum permissible errors (MPEs) for metrological characteristics of measuring equipment].
ISO 14253-2:2011 introduces the Procedure for Uncertainty MAnagement (PUMA), which is a practical, iterative procedure based on the GUM for estimating uncertainty of measurement without changing the basic concepts of the GUM. It is intended to be used generally for estimating uncertainty of measurement and giving statements of uncertainty for: single measurement results; the comparison of two or more measurement results; the comparison of measurement results from one or more workpieces or pieces of measurement equipment with given specifications [i.e. maximum permissible errors (MPEs) for a metrological characteristic of a measurement instrument or measurement standard, and tolerance limits for a workpiece characteristic, etc.], for proving conformance or non-conformance with the specification.
The iterative method is based basically on an upper bound strategy, i.e. overestimation of the uncertainty at all levels, but the iterations control the amount of overestimation. Intentional overestimation and not underestimation, is necessary to prevent wrong decisions based on measurement results. The amount of overestimation is controlled by economical evaluation of the situation.
The iterative method is a tool to maximize profit and minimize cost in the metrological activities of a company. The iterative method/procedure is economically self-adjusting and is also a tool to change/reduce existing uncertainty in measurement with the aim of reducing cost in metrology (manufacture). The iterative method makes it possible to compromise between risk, effort and cost in uncertainty estimation and budgeting.
Geometrische Produktspezifikationen (GPS) - Prüfung von Werkstücken und Messgeräten durch Messungen - Teil 2: Leitfaden zur Schätzung der Unsicherheit von GPS-Messungen bei der Kalibrierung von Messgeräten und bei der Produktprüfung (ISO 14253-2:2011)
Diese Technische Spezifikation enthält Leitlinien für die Einführung des Konzepts des „Leitfadens zur Angabe der Unsicherheit beim Messen“ (abgekürzt GUM), welcher in der Industrie bei der Kalibrierung von Normalen und Messeinrichtungen im GPS-Bereich und bei der Messung von Werkstück-GPS-Merkmalen angewendet werden soll. Ziel ist es, eine vollständige Information darüber zu geben, wie die Angaben zur Unsicherheit ermittelt werden können, sowie die Schaffung einer Grundlage für den internationalen Vergleich von Mess¬ergebnissen und deren Unsicherheit (Beziehung zwischen Abnehmer und Hersteller).
Diese Technische Spezifikation soll ISO 14253-1 unterstützen und ist mit ISO 14253-1 für alle technischen Aufgaben in einem Unternehmen entsprechend der GPS-Spezifikationen (d. h. für Toleranzen der Merkmale von Werkstücken und den Werten der maximal zulässigen Abweichungen (MPE) für messtechnische Merk-male von Messeinrichtungen) nützlich.
Diese Technische Spezifikation führt eine Prozedur für das Unsicherheits-MAnagement — PUMA — ein. Es handelt sich um ein praktisches, iteratives, auf dem GUM basierendes Verfahren zur Schätzung der Unsicher¬heit ohne Änderung des Grundlagenkonzeptes von GUM und soll allgemein zur Schätzung der Messun¬sicherheit und zur Angabe der Unsicherheit in folgenden Teilen dienen:
- Einzelmessergebnisse;
- den Vergleich von zwei oder mehreren Messergebnissen;
- den Vergleich von Messergebnissen — eines oder mehrerer Werkstücke oder Messeinrichtungen — mit gegebenen Spezifikationen (d. h. die maximal zulässigen Abweichungen (MPE) eines messtechnischen Merkmals eines Messgerätes oder eines Normals und die Toleranzgrenzen eines Werkstückmerkmals usw.), um Übereinstimmung oder Nichtübereinstimmung mit der Spezifikation festzustellen.
Spécification géométrique des produits (GPS) - Vérification par la mesure des pièces et des équipements de mesure - Partie 2: Lignes directrices pour l'estimation de l'incertitude dans les mesures GPS, dans l'étalonnage des équipements de mesure et dans la vérification des produits (ISO 14253-2:2011)
L'ISO 14253-2:2011 donne des lignes directrices pour la mise en ?uvre du concept de «Guide pour l'estimation de l'incertitude de mesure» (en abrégé GUM), à appliquer dans l'industrie pour l'étalonnage d'étalons et d'équipements de mesure dans le domaine GPS et la mesure des caractéristiques GPS de pièces. L'objectif est de présenter des informations complètes sur la façon d'obtenir les composantes d'incertitude et de fournir la base d'une comparaison internationale des résultats de mesure et de leurs incertitudes (relation entre le client et le fournisseur).
L'ISO 14253-2:2011 vient à l'appui de l'ISO 14253‑1. Ces deux parties sont bénéfiques à toutes les fonctions techniques d'une société dans l'interprétation des spécifications GPS [à savoir les tolérances des caractéristiques d'une pièce et les valeurs des erreurs maximales tolérées (MPE: Maximum Permissible Errors) pour les caractéristiques métrologiques de l'équipement de mesure].
L'ISO 14253-2:2011 introduit la procédure pour le management de l'incertitude (PUMA: Procedure for Uncertainty MAnagement), qui est une procédure pratique et itérative fondée sur le GUM pour estimer l'incertitude de mesure sans modifier les concepts de base du GUM. Elle est destinée à être utilisée d'une façon générale pour estimer l'incertitude de mesure et pour donner des composantes d'incertitude concernant des résultats de mesure unitaires; la comparaison de deux résultats de mesure ou plus; la comparaison de résultats de mesure à partir d'une ou de plusieurs pièces ou équipements de mesure avec des spécifications données [à savoir les erreurs maximales tolérées (MPE) pour une caractéristique métrologique d'un instrument de mesure ou un étalon, et les limites de tolérance pour une caractéristique de pièce, etc.] pour prouver la conformité ou la non-conformité aux spécifications.
La méthode itérative est fondamentalement basée sur une stratégie de limite supérieure, à savoir la surestimation de l'incertitude à tous les niveaux, mais les itérations déterminent la quantité de surestimation. Une surestimation intentionnelle, et non une sous-estimation, est nécessaire pour empêcher la prise de mauvaises décisions sur la base de résultats de mesure. La quantité de surestimation est contrôlée par l'évaluation économique de la situation.
La méthode itérative est un outil pour maximiser les profits et réduire les coûts des activités métrologiques d'une société. La méthode/procédure itérative est autorégulante sur le plan économique et est également un outil permettant de modifier/réduire l'incertitude de mesure existante avec pour but de réduire le coût de la métrologie (fabrication). La méthode itérative rend possible un compromis entre le risque, l'effort et le coût dans l'estimation et la budgétisation de l'incertitude.
Specifikacija geometrijskih veličin izdelka - Preskusi z merjenjem obdelovancev in merilne opreme - 2. del: Navodila za ugotavljanje negotovosti pri meritvi geometrijske veličine izdelka, pri umerjanju merilne opreme in pri preverjanju izdelka (ISO 14253-2:2011)
Ta tehnična specifikacija podaja navodila za izvajanje koncepta »Vodilo za ugotavljanje negotovosti pri merjenju« (skrajšano GUM) v industriji pri umerjanju (merilnih) standardov in merilne opreme pri specifikaciji geometrijskih veličin izdelka in merjenju karakteristik geometrijske veličine obdelovanca.
Cilj je spodbujati popolne informacije o tem, kako doseči izjave o negotovosti, in podati osnovo za mednarodno primerjavo rezultatov meritev in njihovih negotovostih (odnos med kupcem in dobaviteljem).
Ta tehnična specifikacija podpira ISO 14253-1. Ta tehnična specifikacija in ISO 14253-1 sta koristna za vse tehnične funkcije v podjetju pri razlagi specifikacij geometrijskih veličin izdelka (tj. tolerance značilnosti obdelovancev in vrednosti maksimalnih dovoljenih napak (MPE) za meroslovne karakteristike merilne opreme).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2011
1DGRPHãþD
SIST ENV ISO 14253-2:2002
SIST ISO/TS 14253-2:2002
6SHFLILNDFLMDJHRPHWULMVNLKYHOLþLQL]GHOND3UHVNXVL]PHUMHQMHPREGHORYDQFHYLQ
PHULOQHRSUHPHGHO 1DYRGLOD]DXJRWDYOMDQMHQHJRWRYRVWLSULPHULWYL
JHRPHWULMVNHYHOLþLQHL]GHONDSULXPHUMDQMXPHULOQHRSUHPHLQSULSUHYHUMDQMX
L]GHOND ,62
Geometrical product specifications (GPS) - Inspection by measurement of workpieces
and measuring equipment - Part 2: Guidance for the estimation of uncertainty in GPS
measurement, in calibration of measuring equipment and in product verification (ISO
14253-2:2011)
Geometrische Produktspezifikationen (GPS) - Prüfung von Werkstücken und
Messgeräten durch Messungen - Teil 2: Leitfaden zur Schätzung der Unsicherheit von
GPS-Messungen bei der Kalibrierung von Messgeräten und bei der Produktprüfung (ISO
14253-2:2011)
Spécification géométrique des produits (GPS) - Vérification par la mesure des pièces et
des équipements de mesure - Partie 2: Lignes directrices pour l'estimation de
l'incertitude dans les mesures GPS, dans l'étalonnage des équipements de mesure et
dans la vérification des produits (ISO 14253-2:2011)
Ta slovenski standard je istoveten z: EN ISO 14253-2:2011
ICS:
17.040.30 Merila Measuring instruments
17.040.40 6SHFLILNDFLMDJHRPHWULMVNLK Geometrical Product
YHOLþLQL]GHOND *36 Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 14253-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2011
ICS 17.040.01 Supersedes ENV ISO 14253-2:2001
English Version
Geometrical product specifications (GPS) - Inspection by
measurement of workpieces and measuring equipment - Part 2:
Guidance for the estimation of uncertainty in GPS measurement,
in calibration of measuring equipment and in product verification
(ISO 14253-2:2011)
Spécification géométrique des produits (GPS) - Vérification Geometrische Produktspezifikationen (GPS) - Prüfung von
par la mesure des pièces et des équipements de mesure -
Werkstücken und Messgeräten durch Messen - Teil 2:
Partie 2: Lignes directrices pour l'estimation de l'incertitude Leitfaden zur Schätzung der Unsicherheit von GPS-
dans les mesures GPS, dans l'étalonnage des Messungen bei der Kalibrierung von Messgeräten und bei
équipements de mesure et dans la vérification des produits der Produktprüfung (ISO 14253-2:2011)
(ISO 14253-2:2011)
This European Standard was approved by CEN on 14 April 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14253-2:2011: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Foreword
This document (EN ISO 14253-2:2011) has been prepared by Technical Committee ISO/TC 213 "Dimensional
and geometrical product specifications and verification" in collaboration with Technical Committee
CEN/TC 290 “Dimensional and geometrical product specification and verification” the secretariat of which is
held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2011, and conflicting national standards shall be withdrawn at
the latest by October 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes ENV ISO 14253-2:2001.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 14253-2:2011 has been approved by CEN as a EN ISO 14253-2:2011 without any
modification.
INTERNATIONAL ISO
STANDARD 14253-2
First edition
2011-04-15
Geometrical product specifications
(GPS) — Inspection by measurement of
workpieces and measuring equipment —
Part 2:
Guidance for the estimation
of uncertainty in GPS measurement,
in calibration of measuring equipment
and in product verification
Spécification géométrique des produits (GPS) — Vérification
par la mesure des pièces et des équipements de mesure —
Partie 2: Lignes directrices pour l'estimation de l'incertitude dans les
mesures GPS, dans l'étalonnage des équipements de mesure et dans
la vérification des produits
Reference number
ISO 14253-2:2011(E)
©
ISO 2011
ISO 14253-2:2011(E)
© ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.2
3 Terms and definitions .2
4 Symbols.4
5 Concept of the iterative GUM method for estimation of uncertainty of measurement .5
6 Procedure for Uncertainty MAnagement — PUMA .6
6.1 General .6
6.2 Uncertainty management for a given measurement process.6
6.3 Uncertainty management for design and development of a measurement
process/procedure .7
7 Sources of errors and uncertainty of measurement.10
7.1 Types of errors .10
7.2 Environment for the measurement.12
7.3 Reference element of measurement equipment .12
7.4 Measurement equipment .12
7.5 Measurement set-up (excluding the placement and clamping of the workpiece) .13
7.6 Software and calculations .13
7.7 Metrologist .13
7.8 Measurement object, workpiece or measuring instrument characteristic.13
7.9 Definition of the GPS characteristic, workpiece or measuring instrument characteristic.14
7.10 Measuring procedure.14
7.11 Physical constants and conversion factors .14
8 Tools for the estimation of uncertainty components, standard uncertainty and expanded
uncertainty .14
8.1 Estimation of uncertainty components.14
8.2 Type A evaluation for uncertainty components.15
8.3 Type B evaluation for uncertainty components.15
8.4 Common Type A and B evaluation examples.17
8.5 Black and transparent box model of uncertainty estimation.20
8.6 Black box method of uncertainty estimation — Summing of uncertainty components into
combined standard uncertainty, u .21
c
8.7 Transparent box method of uncertainty estimation — Summing of uncertainty
components into combined standard uncertainty, u .21
c
8.8 Evaluation of expanded uncertainty, U, from combined standard uncertainty, u .22
c
8.9 Nature of the uncertainty of measurement parameters u and U.22
c
9 Practical estimation of uncertainty — Uncertainty budgeting with PUMA.23
9.1 General .23
9.2 Preconditions for an uncertainty budget.23
9.3 Standard procedure for uncertainty budgeting .24
10 Applications .26
10.1 General .26
10.2 Documentation and evaluation of the uncertainty value .27
10.3 Design and documentation of the measurement or calibration procedure .27
10.4 Design, optimization and documentation of the calibration hierarchy .28
ISO 14253-2:2011(E)
10.5 Design and documentation of new measurement equipment . 29
10.6 Requirements for and qualification of the environment. 29
10.7 Requirements for and qualification of measurement personnel. 29
Annex A (informative) Example of uncertainty budgets — Calibration of a setting ring. 31
Annex B (informative) Example of uncertainty budgets — Design of a calibration hierarchy. 38
Annex C (informative) Example of uncertainty budgets — Measurement of roundness . 63
Annex D (informative) Relation to the GPS matrix model. 69
Bibliography. 71
iv © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14253-2 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
This first edition of ISO 14253-2 cancels and replaces ISO/TS 14253-2:1999, which has been technically
revised. It also incorporates the Technical Corrigendum ISO/TS 14253-2:1999/Cor.1:2007.
ISO 14253 consists of the following parts, under the general title Geometrical product specifications (GPS) —
Inspection by measurement of workpieces and measuring equipment:
⎯ Part 1: Decision rules for proving conformance or non-conformance with specifications
⎯ Part 2: Guidance for the estimation of uncertainty in GPS measurement, in calibration of measuring
equipment and in product verification
⎯ Part 3: Guidelines for achieving agreements on measurement uncertainty statements
⎯ Part 4: Background on functional limits and specification limits in decision rules [Technical Specification]
ISO 14253-2:2011(E)
Introduction
This part of ISO 14253 is a global GPS standard (see ISO/TR 14638:1995). This global GPS standard
influences chain links 4, 5 and 6 in all chains of standards.
The ISO/GPS Masterplan given in ISO/TR 14638 gives an overview of the ISO/GPS system of which this
document is a part. The fundamental rules of ISO/GPS given in ISO 8015 apply to this document and the
default decision rules given in ISO 14253-1 apply to specifications made in accordance with this document,
unless otherwise indicated.
For more detailed information on the relation of this International Standard to other standards and to the GPS
matrix model, see Annex D.
This part of ISO 14253 has been developed to support ISO 14253-1. This part of ISO 14253 establishes a
simplified, iterative procedure of the concept and the way to evaluate and determine uncertainty (standard
uncertainty and expanded uncertainty) of measurement, and the recommendations of the format to document
and report the uncertainty of measurement information as given in the Guide to the expression of uncertainty
in measurement (GUM). In most cases, only very limited resources are necessary to estimate uncertainty of
measurement by this simplified, iterative procedure, but the procedure may lead to a slight overestimation of
the uncertainty of measurement. If a more accurate estimation of the uncertainty of measurement is needed,
the more elaborated procedures of the GUM need to be applied.
This simplified, iterative procedure of the GUM methods is intended for GPS measurements, but may be used
in other areas of industrial (applied) metrology.
The uncertainty of measurement and the concept of handling uncertainty of measurement are important to all
the technical functions within a company. This part of ISO 14253 is relevant to several technical functions,
including management, design and development, manufacturing, quality assurance and metrology.
This part of ISO 14253 is of special importance in relation to ISO 9000 quality assurance systems, e.g. it is a
requirement that methods for monitoring and measurement of the quality management system processes are
suitable. The measurement uncertainty is a measure of the process suitability.
In this part of ISO 14253, the uncertainty of the result of a process of calibration and a process of
measurement is handled in the same way:
⎯ calibration is treated as a “measurement of the metrological characteristics of a measuring equipment or
a measurement standard”;
⎯ measurement is treated as a “measurement of the geometrical characteristics of a workpiece”.
Therefore, in most cases, no distinction is made in the text between measurement and calibration. The term
“measurement” is used as a synonym for both.
vi © ISO 2011 – All rights reserved
INTERNATIONAL STANDARD ISO 14253-2:2011(E)
Geometrical product specifications (GPS) — Inspection
by measurement of workpieces and measuring equipment —
Part 2:
Guidance for the estimation of uncertainty in GPS measurement,
in calibration of measuring equipment and in product
verification
1 Scope
This part of ISO 14253 gives guidance on the implementation of the concept of the “Guide to the estimation of
uncertainty in measurement” (in short GUM) to be applied in industry for the calibration of (measurement)
standards and measuring equipment in the field of GPS and the measurement of workpiece GPS
characteristics. The aim is to promote full information on how to achieve uncertainty statements and provide
the basis for international comparison of measurement results and their uncertainties (relationship between
purchaser and supplier).
This part of ISO 14253 is intended to support ISO 14253-1. Both parts are beneficial to all technical functions
in a company in the interpretation of GPS specifications [i.e. tolerances of workpiece characteristics and
values of maximum permissible errors (MPEs) for metrological characteristics of measuring equipment].
This part of ISO 14253 introduces the Procedure for Uncertainty MAnagement (PUMA), which is a practical,
iterative procedure based on the GUM for estimating uncertainty of measurement without changing the basic
concepts of the GUM. It is intended to be used generally for estimating uncertainty of measurement and giving
statements of uncertainty for:
⎯ single measurement results;
⎯ the comparison of two or more measurement results;
⎯ the comparison of measurement results — from one or more workpieces or pieces of measurement
equipment — with given specifications [i.e. maximum permissible errors (MPEs) for a metrological
characteristic of a measurement instrument or measurement standard, and tolerance limits for a
workpiece characteristic, etc.], for proving conformance or non-conformance with the specification.
The iterative method is based basically on an upper bound strategy, i.e. overestimation of the uncertainty at all
levels, but the iterations control the amount of overestimation. Intentional overestimation — and not under-
estimation — is necessary to prevent wrong decisions based on measurement results. The amount of
overestimation is controlled by economical evaluation of the situation.
The iterative method is a tool to maximize profit and minimize cost in the metrological activities of a company.
The iterative method/procedure is economically self-adjusting and is also a tool to change/reduce existing
uncertainty in measurement with the aim of reducing cost in metrology (manufacture). The iterative method
makes it possible to compromise between risk, effort and cost in uncertainty estimation and budgeting.
ISO 14253-2:2011(E)
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 14253-1:1998, Geometrical Product Specifications (GPS) — Inspection by measurement of workpieces
and measuring equipment — Part 1: Decision rules for proving conformance or non-conformance with
specifications
ISO 14660-1:1999, Geometrical Product Specifications (GPS) — Geometrical features — Part 1: General
terms and definitions
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14253-1, ISO 14660-1,
ISO/IEC Guide 98-3 and ISO/IEC Guide 99 and the following apply.
3.1
black box model for uncertainty estimation
model for uncertainty estimation in which the uncertainties associated with the relevant input quantities are
directly represented by their influence on the quantity value being attributed to a measurand (in the units of the
measurand)
NOTE 1 The “quantity value being attributed to a measurand” is typically a measured value.
NOTE 2 In many cases, a complex method of measurement may be looked upon as one simple black box with
stimulus in and result out from the black box. When a black box is opened, it may turn out to contain several “smaller”
black boxes or several transparent boxes, or both.
NOTE 3 The method of uncertainty estimation remains a black box method even if it is necessary to make
supplementary measurements to determine the values of influence quantities in order to make corresponding corrections.
3.2
transparent box model for uncertainty estimation
model for uncertainty estimation in which the relationship between the input quantities and the quantity value
being attributed to a measurand is explicitly expressed with equations or algorithms
3.3
measuring task
quantification of a measurand according to its definition
3.4
overall measurement task
measurement task that quantifies the final measurand
3.5
intermediate measurement task
measurement task obtained by subdividing the overall measurement task into simpler parts
NOTE 1 The subdivision of the overall measuring task serves the goal of simplification of the evaluation of uncertainty.
NOTE 2 The specific subdivisions are arbitrary, as is whether to subdivide at all.
2 © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
3.6
target uncertainty
U
T
〈for a measurement or calibration〉 uncertainty determined as the optimum for the measuring task
NOTE 1 Target uncertainty is the result of a management decision involving e.g. design, manufacturing, quality
assurance, service, marketing, sales and distribution.
NOTE 2 Target uncertainty is determined (optimized) taking into account the specification [tolerance or maximum
permissible error (MPE)], the process capability, cost, criticality and the requirements of ISO 9001, ISO 9004 and
ISO 14253-1.
NOTE 3 See also 8.8.
3.7
required uncertainty of measurement
U
R
uncertainty required for a given measurement process and task
NOTE See also 6.2. The required uncertainty may be specified by, for example, a customer.
3.8
uncertainty management
process of deriving an adequate measurement procedure from the measuring task and the target uncertainty
by using uncertainty budgeting techniques
3.9
uncertainty budget
〈for a measurement or calibration〉 statement summarizing the estimation of the uncertainty components that
contributes to the uncertainty of a result of a measurement
NOTE 1 The uncertainty of the result of the measurement is unambiguous only when the measurement procedure
(including the measurement object, measurand, measurement method and conditions) is defined.
NOTE 2 The term “budget” is used for the assignment of numerical values to the uncertainty components and their
combination and expansion, based on the measurement procedure, measurement conditions and assumptions.
3.10
uncertainty component
xx
source of uncertainty of measurement for a measuring process
3.11
limit value (variation limit) for an uncertainty component
a
xx
absolute value of the extreme value(s) of the uncertainty component, xx
3.12
uncertainty component
u
xx
standard uncertainty of the uncertainty component, xx
NOTE The iteration method uses the designation u for all uncertainty components.
xx
3.13
influence quantity of a measurement instrument
characteristic of a measuring instrument that affects the result of a measurement performed by the instrument
3.14
influence quantity of a workpiece
characteristic of a workpiece that affects the result of a measurement performed on that workpiece
ISO 14253-2:2011(E)
4 Symbols
For the purposes of this document, the generic symbols given in Table 1 apply.
Table 1 — Generic symbols
Symbol/
abbreviated Description
term
a limit value for a distribution
a limit value for an error or uncertainty component (in the unit of the measurement result, of the measurand)
xx
a* limit value for an error or uncertainty component (in the unit of the influence quantity)
xx
α linear coefficient of thermal expansion
b coefficient for transformation of a to u
xx xx
C correction (value)
d resolution of a measurement equipment
E Young's modulus
ER error (value of a measurement)
G function of several measurement values [G(X , X , . X , .)]
1 2 i
h hysteresis value
k coverage factor
m number of standard deviations in the half of a confidence interval
MR measurement result (value)
n number of .
N number of iterations
ν Poisson's number
p number of total uncorrelated uncertainty components
r number of total correlated uncertainty components
ρ correlation coefficient
t safety factor calculated based on the Student t distribution
TV true value of a measurement
u, u standard uncertainty (standard deviation)
i
s standard deviation of a sample
x
s standard deviation of a mean value of a sample
x
u combined standard uncertainty
c
u standard deviation of uncertainty component xx — uncertainty component
xx
U expanded uncertainty of measurement
U true uncertainty of measurement
A
U conventional true uncertainty of measurement
C
U approximated uncertainty of measurement (number of iteration not stated)
E
U approximated uncertainty of measurement of iteration number N
EN
U required uncertainty
R
U target uncertainty
T
U uncertainty value (not estimated according to GUM or this part of ISO 14253)
V
X measurement result (uncorrected)
X measurement result (in the transparent box model of uncertainty estimation)
i
Y measurement result (corrected)
4 © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
5 Concept of the iterative GUM method for estimation of uncertainty
of measurement
By applying the GUM method completely, a conventional true uncertainty of measurement, U , can be found.
C
The simplified, iterative method described in this part of ISO 14253 sets out to achieve estimated uncertainties
of measurements, U , by overestimating the influencing uncertainty components (U W U ). The process of
E E C
overestimating provides “worst-case contributions” at the upper bound from each known or predictable
uncertainty component, thus ensuring results of estimations “on the safe side”, i.e. not underestimating the
uncertainty of measurement. The method is based on the following:
⎯ all uncertainty components are identified;
⎯ it is decided which of the possible corrections shall be made (see 8.4.6);
⎯ the influence on the uncertainty of the measurement result from each component is evaluated as a
standard uncertainty u , called the uncertainty component;
xx
⎯ an iteration process, PUMA (see Clause 6) is undertaken;
⎯ the evaluation of each of the uncertainty components (standard uncertainties) u can take place either by
xx
a Type A evaluation or by a Type B evaluation;
⎯ Type B evaluation is preferred — if possible — in the first iteration in order to get a rough uncertainty
estimate to establish an overview and to save cost;
⎯ the total effect of all components (called the combined standard uncertainty) is calculated by Equation (1):
22 2 2
uu=+u+u+ .+u (1)
c1x xx2 3 xn
⎯ Equation (1) is only valid for a black box model of the uncertainty estimation and when the components
u are all uncorrelated (for more details and other equations, see 8.6 and 8.7);
xx
⎯ for simplification, the only correlation coefficients between components considered are
r = 1, −1, 0 (2)
If the uncertainty components are not known to be uncorrelated, full correlation is assumed, either ρ = 1
or ρ = −1. Correlated components are added arithmetically before put into the formula above (see 8.5
and 8.6);
⎯ the expanded uncertainty U is calculated by Equation (3):
Uk=¥u (3)
c
where k = 2; k is the coverage factor (see also 8.8).
The simplified, iterative method normally will consist of at least two iterations of estimating the components of
uncertainty:
a) the first very rough, quick and cheap iteration has the purpose of identifying the largest components of
uncertainty (see Figure 1);
b) the following iterations — if any — only deal with making more accurate “upper bound” estimates of the
largest components to lower the estimate of the uncertainty (u and U) to a possible acceptable
c
magnitude.
ISO 14253-2:2011(E)
The simplified and iterative method may be used for two purposes:
1) management of the uncertainty of measurement for a result of a given measurement process (can be
used for the results from a known measuring process or for comparison of two or more of such results) —
see 6.2;
2) uncertainty management for a measuring process. For the development of an adequate measuring
process, i.e. U u U , see 6.3.
E T
6 Procedure for Uncertainty MAnagement — PUMA
6.1 General
The prerequisite for uncertainty budgeting and management is a clearly identified and defined measuring task,
i.e. the measurand to be quantified (a GPS characteristic of a workpiece or a metrological characteristic of a
GPS measuring equipment). The uncertainty of measurement is a measure of the quality of the measured
value according to the definitions of a GPS characteristic of the workpiece or a metrological characteristic of
the GPS measuring equipment given in GPS standards.
GPS standards define the “conventional true values” of the characteristics to be measured by chains of
standards and global standards (see ISO/TR 14638). GPS standards in many cases also define the ideal —
or conventional true — principle of measurement (see ISO/IEC Guide 99:2007, 2.4), method of measurement
(see ISO/IEC Guide 99:2007, 2.5), measurement procedure (see ISO/IEC Guide 99:2007, 2.6) and standard
“reference conditions” (see ISO/IEC Guide 99:2007, 4.11).
Deviations from the standardized conventional true values of the characteristics, etc. (the ideal operator) are
contributing to the uncertainty of measurement.
6.2 Uncertainty management for a given measurement process
Management of the uncertainty of measurement for a given measuring task (box 1 of Figure 1) and for an
existing measurement process is illustrated in Figure 1. The principle of measurement (box 3), measurement
method (box 4), measurement procedure (box 5) and measurement conditions (box 6) are fixed and given or
decided in this case, and cannot be changed. The only task is to evaluate the consequence on the uncertainty
of measurement. A required U may be given or decided.
R
Using the iterative GUM method, the first iteration is only for orientation, and to look for the dominant
uncertainty components. The only thing to do — in the management process in this case — is to refine the
estimation of the dominant components to come closer to a true estimate of the uncertainty components thus
avoiding an excessive overestimate — if necessary.
Figure 1 — Uncertainty management for a measurement result from a given measurement process
6 © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
The procedure is as follows.
a) Make a first iteration based preferably on a black box model of the uncertainty estimation process and set
up a preliminary uncertainty budget (boxes 7 to 9) leading to the first rough estimate of the expanded
uncertainty, U (box 10). For details about uncertainty estimation, see Clause 9. All estimates of
E1
uncertainties U are performed as upper bound estimates.
EN
b) Compare the first estimated uncertainty, U , with the required uncertainty U (box A) for the actual
E1 R
measuring task.
1) If U is acceptable (i.e. if U u U ), then the uncertainty budget of the first iteration has proven that
E1 E1 R
the given measurement procedure is adequate for the measuring task (box 11).
2) If U is not acceptable (i.e. if U > U ) or if there is no required uncertainty, but a lower and more
E1 E1 R
true value is desired, the iteration process continues.
c) Before the new iteration, analyse the relative magnitude of the uncertainty components. In many cases, a
few uncertainty components dominate the combined standard uncertainty and expanded uncertainty.
d) Change the assumptions or improve the knowledge about the uncertainty components to make a more
accurate (see ISO/IEC Guide 99:2007, 2.13) upper bound estimation of the largest (dominant) uncertainty
components (box 12).
Change to a more detailed model of the uncertainty estimation process or a higher resolution of the
measuring process (box 12).
e) Make the second iteration of the uncertainty budget (boxes 7 to 9) leading to the second, lower and more
accurate (see ISO/IEC Guide 99:2007, 2.13) upper bound estimate of the uncertainty of measurement,
U (box 10).
E2
f) Compare the second estimated uncertainty U (box A) with uncertainty required U for the actual
E2 R
measuring task.
1) If U is acceptable (i.e. if U u U ), then the uncertainty budget of the second iteration has proven
E2 E2 R
that the given measurement procedure is adequate to the measuring task (box 11).
2) If U is not acceptable (i.e. if U > U ), or if there is no required uncertainty, but a lower and more
E2 E2 R
true value is desired, then a third (and possibly more) iteration(s) is (are) needed. Repeat the
analysis of the uncertainty components [additional changes of assumptions, improvements in
knowledge, changes in modelling, etc. (box 12)] and concentrate on the currently largest uncertainty
components.
g) When all possibilities have been used for making more accurate (lower) upper bound estimates of the
measuring uncertainties without coming to an acceptable measuring uncertainty U u U , then it is
EN R
proven that it is not possible to fulfil the given requirement U .
R
6.3 Uncertainty management for design and development of a measurement
process/procedure
Uncertainty management in this case is performed to develop an adequate measurement procedure
[measurement of the geometrical characteristics of a workpiece or the metrological characteristics of a
measuring equipment (calibration)]. Uncertainty management is performed on the basis of a defined
measuring task (box 1 in Figure 2) and a given target uncertainty, U (box 2). Definitions of the measuring
T
task and target uncertainty are company policy decisions to be made at a sufficiently high management level.
An adequate measurement procedure is a procedure which results in an estimated uncertainty of
measurement less than or equal to the target uncertainty. If the estimated uncertainty of measurement is
much less than the target uncertainty, the measurement procedure may not be (economically) optimal for
performing the measuring task (i.e. the measurement process is too costly).
ISO 14253-2:2011(E)
The PUMA, based on a given measuring task (box 1) and a given target uncertainty U (box 2), includes the
T
following (see Figure 2).
a) Choose the principle of measurement (box 3) on the basis of experience and possible measurement
instruments present in the company.
b) Set up and document a preliminary method of measurement (box 4), measurement procedure (box 5)
and measurement conditions (box 6) on the basis of experience and known possibilities in the company.
c) Make a first iteration based preferably on a black box model of the uncertainty estimation process and set
up a preliminary uncertainty budget (boxes 7 to 9) leading to the first rough estimate of the expanded
uncertainty, U (box 10). For details about uncertainty estimation, see Clause 9. All estimates of
E1
uncertainties U are performed as upper bound estimates.
EN
d) Compare the first estimated uncertainty, U , with the given target uncertainty, U (box A).
E1 T
1) If U is acceptable (i.e. if U u U ), then the uncertainty budget of the first iteration has proven that
E1 E1 T
the measurement procedure is adequate for the measuring task (box 11).
2) If U << U , then the measurement procedure is technically acceptable, but a possibility may exist
E1 T
to change the method or the procedure (box 13), or both, in order to make the measuring process
more cost effective while increasing the uncertainty. A new iteration is then needed to estimate the
resulting measurement uncertainty, U (box 10).
E2
3) If U is not acceptable (i.e. if U > U ), the iteration process continues, or it is concluded that no
E1 E1 T
adequate measurement procedure is possible.
e) Before the new iteration, analyse the relative magnitude of the uncertainty components. In many cases, a
few uncertainty components predominate the combined standard uncertainty and expanded uncertainty.
f) If U > U , then change the assumptions or the modelling or increase the knowledge about the
E1 T
uncertainty components (box 12) to make a more accurate (see ISO/IEC Guide 99:2007, 2.13) upper
bound estimation of the largest (dominant) uncertainty components.
g) Make the second iteration of the uncertainty budget (boxes 7 to 9) leading to the second, lower and more
accurate (see ISO/IEC Guide 99:2007, 2.13) upper bound estimate of the uncertainty of measurement,
U (box 10).
E2
h) Compare the second estimated uncertainty U with the given target uncertainty, U (box A).
E2 T
1) If U is acceptable (i.e. if U u U ), then the uncertainty budget of the second iteration has proven
E2 E2 T
that the measurement procedure is adequate for the measuring task (box 11).
2) If U is not acceptable (i.e. if U > U ), then a third (and possibly more) iteration(s) is (are) needed.
E2 E2 T
Repeat the analysis of the uncertainty components [additional changes of assumptions, modelling
and increase in knowledge (box 12)] and concentrate on the currently largest uncertainty
components.
i) When all possibilities have been used for making more accurate (lower) upper bound estimates of the
measuring uncertainties without coming to an acceptable measuring uncertainty U u U , then it is
EN T
necessary to change the measurement method or the measurement procedure or the conditions of
measurement (box 13) to (possibly) bring down the magnitude of the estimated uncertainty, U . The
EN
iteration procedure starts again with a first iteration.
j) If changes in the measurement method or the measurement procedure or conditions (box 13) do not lead
to an acceptable uncertainty of measurement, it is possible to change the principle of measurement
(box 14) and start the above-mentioned procedure again.
k) If changing the measuring principle and the related iterations described above still does not lead to an
acceptable uncertainty of measurement, the ultimate possibility is to change the measuring task or target
uncertainty (box 15), or both, and to start the above-mentioned procedure again.
8 © ISO 2011 – All rights reserved
ISO 14253-2:2011(E)
l) If changing the measuring task or target uncertainty is not possible, it has been demonstrated that no
adequate measurement procedure exists (box 16).
Figure 2 — Procedure for Uncertainty of Measurement MAnagement (PUMA)
for a measurement process/procedure
ISO 14253-2:2011(E)
7 Sources of errors and uncertainty of measurement
7.1 Types of errors
Different types of errors regularly show up in measurement results:
⎯ systematic errors;
⎯ random errors;
⎯ drift;
⎯ outliers.
All errors are by nature systematic. When errors are perceived as non-systematic, it is either because the
reason for the error is not looked for or because the level of resolution is not sufficient. Systematic errors may
be characterized by size and sign (+ or −).
ER = MR − TV
where
ER is the error;
MR is the measurement result;
TV is the
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...