1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 22514-7:2012Statistical methods in processmanagement Capability andperformancePart 7: Capability of measurementprocessesBS ISO 22514-7:2012 BRITISH STANDARDNational forewo
2、rdThis British Standard is the UK implementation of ISO 22514-7:2012. The UK participation in its preparation was entrusted to TechnicalCommittee SS/4, Statistical Process Management.A list of organizations represented on this committee can be obtained on request to its secretary.This publication do
3、es not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 71185 5 ICS 03.120.30 Compliance with a British Standard cannot confer immunity from
4、legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 22514-7:2012 ISO 2012Statistical methods in process management Capability and performanc
5、e Part 7: Capability of measurement processesMthodes statistiques dans la gestion de processus Aptitude et performance Partie 7: Aptitude des processus de mesureINTERNATIONAL STANDARDISO22514-7First edition2012-09-15Reference numberISO 22514-7:2012(E)BS ISO 22514-7:2012ISO 22514-7:2012(E)ii ISO 2012
6、 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All 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 I
7、SO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 22514-7:2012ISO 22514-7:2012(E) ISO 2012 All rights reserve
8、d iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 24 Symbols and abbreviated terms . 64.1 Symbols . 64.2 Abbreviated terms . 85 Basic principles . 95.1 General . 95.2 Resolution . 115.3 MPE known and used . 115.4 Capability and performance limits
9、 for measuring system and measurement process . 116 Implementation 116.1 General . 116.2 Factors that influence the measurement process 117 Studies for calculating the uncertainty components 177.1 Measuring system .177.2 Uncertainty components of the measurement process .228 Calculation of combined
10、uncertainty .228.1 General .228.2 Calculation of expanded uncertainty .249 Capability 249.1 Performance ratios .249.2 Capability indices 2510 Capability of the measurement process compared to the capability of the production process .2510.1 Relation between observed process capability and measuremen
11、t capability ratio .2510.2 Relation between observed process capability and measurement capability .2711 Ongoing review of the measurement process stability 2711.1 Ongoing review of the stability 2711.2 Monitoring linearity .2812 Capability of attribute measurement processes .2912.1 General .2912.2
12、Capability calculations without using reference values .2912.3 Capability calculations using reference values 3012.4 Ongoing review 34Annex A (informative) Examples 35Annex B (informative) Statistical methods used 41Bibliography .46BS ISO 22514-7:2012ISO 22514-7:2012(E)ForewordISO (the International
13、 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 est
14、ablished 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 standardiz
15、ation.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
16、. 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 pa
17、tent rights.ISO 22514-7 was prepared by Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 4, Applications of statistical methods in process management.ISO 22514 consists of the following parts, under the general title Statistical methods in process management Capabi
18、lity and performance: Part 1: General principles and concepts Part 2: Process capability and performance of time-dependent process models Part 3: Machine performance studies for measured data on discrete parts Part 4: Process capability estimates and performance measures Part 6: Process capability s
19、tatistics for characteristics following a multivariate normal distribution Part 7: Capability of measurement processesA future Part 5 on process capability and performance for attributive characteristics is planned. A future Part 8 on the machine performance of a multi-state production process is un
20、der preparation.iv ISO 2012 All rights reservedBS ISO 22514-7:2012ISO 22514-7:2012(E)IntroductionThe purpose of a measurement process is to produce measurement results obtained from defined characteristics on parts or processes. The capability of a measurement process is derived from the statistical
21、 properties of measurements from a measurement process that is operating in a predictable manner.Calculations of capability and performance indices are based on measurement results. The uncertainty of the measurement process used to generate capability and performance indices must be estimated befor
22、e the indices can be meaningful. The actual measurement uncertainty needs to be adequately small.If the measurement process is used to judge whether a characteristic of a product conforms to a specification or not, the uncertainty of the measurement process must be compared to the specification itse
23、lf. If the measurement process is used for process control of a characteristic, the uncertainty needs to be compared with the process variation. Limits of acceptability should be stated for both cases.The quality of measurement results is given by the uncertainty of the measurement process. This is
24、defined by the statistical properties of multiple measurements, or estimates of properties, based on the knowledge of the measurement process.The methods described in this part of ISO 22514 only address the implementation uncertainty. (For more information on implementation uncertainty, see ISO 1745
25、0-2.) Therefore, they are only useful if it is known that the method uncertainty and the specification uncertainty are small compared to the implementation uncertainty. This part of ISO 22514 describes methods to define and calculate capability indices for measurement processes based on estimated un
26、certainties. The approach given in ISO/IEC Guide 98-3, Guide to the expression of uncertainty in measurements (GUM) is the basis of this approach. ISO 2012 All rights reserved vBS ISO 22514-7:2012BS ISO 22514-7:2012Statistical methods in process management Capability and performance Part 7: Capabili
27、ty of measurement processes1 ScopeThis part of ISO 22514 defines a procedure to validate measuring systems and a measurement process in order to state whether a given measurement process can satisfy the requirements for a specific measurement task with a recommendation of acceptance criteria. The ac
28、ceptance criteria are defined as a capability figure (CMS) or a capability ratio (QMS).NOTE 1 This part of ISO 22514 follows the approach taken in ISO/IEC Guide 98-3, Guide to the expression of the uncertainty in measurement (GUM), and establishes a basic, simplified procedure for stating and combin
29、ing uncertainty components used to estimate a capability index for an actual measurement process.NOTE 2 This part of ISO 22514 is primarily developed to be used for simple one-dimensional measurement processes, where it is known that the method uncertainty and the specification uncertainty are small
30、 compared to the implementation uncertainty. It can also be used in similar cases, where measurements are used to estimate process capability or process performance. It is not suitable for complex geometrical measurement processes, such as surface texture, form, orientation and position measurements
31、 that rely on several measurement points or simultaneous measurements in several directions.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest editio
32、n of the referenced document (including any amendments) applies.ISO 3534-1:2006, Statistics Vocabulary and symbols Part 1: General statistical terms and terms used in probabilityISO 3534-2:2006, Statistics Vocabulary and symbols Part 2: Applied statisticsISO 5725-1, Accuracy (trueness and precision)
33、 of measurement methods and results Part 1: General principles and definitionsISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement methodISO 5725-3, Accuracy (truenes
34、s and precision) of measurement methods and result Part 3: Intermediate measures of the precision of a standard measurement methodISO 5725-4, Accuracy (trueness and precision) of measurement methods and results Part 4: Basic methods for the determination of the trueness of a standard measurement met
35、hodISO 5725-5, Accuracy (trueness and precision) of measurement methods and results Part 5: Alternative methods for the determination of the precision of a standard measurement methodISO 5725-6, Accuracy (trueness and precision) of measurement methods and results Part 6: Use in practice of accuracy
36、valuesISO 7870-1, Control charts Part 1: General guidelinesISO/IEC Guide 98-3:2008, Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)INTERNATIONAL STANDARD ISO 22514-7:2012(E) ISO 2012 All rights reserved 1BS ISO 22514-7:2012ISO 22514-7:2012(E)3 Term
37、s and definitionsFor the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 3534-2 and ISO 5725 (all parts), and the following apply.3.1maximum permissible measurement errormaximum permissible errorlimit of errorMPEextreme value of measurement error, with respect to a know
38、n reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring systemNOTE 1 Usually, the term “maximum permissible errors” or “limits of error” is used where there are two extreme values.NOTE 2 The term “tolerance” should not be use
39、d to designate maximum permissible error.ISO/IEC Guide 99:2007, 4.263.2measurandquantity intended to be measuredNOTE 1 The specification of a measurand requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance carrying the quantity, including any rele
40、vant component, and the chemical entities involved.NOTE 2 In the second edition of the VIM and in IEC 60050-300:2001, the measurand is defined as the quantity subject to measurement.NOTE 3 The measurement, including the measuring system and the conditions under which the measurement is carried out,
41、might change the phenomenon, body, or substance such that the quantity being measured may differ from the measurand as defined. In this case, adequate correction is necessary.EXAMPLE 1 The potential difference between the terminals of a battery may decrease when using a voltmeter with a significant
42、internal conductance to perform the measurement. The open-circuit potential difference can be calculated from the internal resistances of the battery and the voltmeter.EXAMPLE 2 The length of a steel rod in equilibrium with the ambient Celsius temperature of 23 C will be different from the length at
43、 the specified temperature of 20 C, which is the measurand. In this case, a correction is necessary.NOTE 4 In chemistry, “analyte”, or the name of a substance or compound, are terms sometimes used for measurand. This usage is erroneous because these terms do not refer to quantities.ISO/IEC Guide 99:
44、2007, 2.33.3measurement uncertaintyuncertainty of measurementuncertaintynon-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand (3.2), based on the information usedNOTE 1 Measurement uncertainty includes components arising from systematic effects,
45、such as components associated with corrections and the assigned quantity values of measurement standards, as well as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead, associated measurement uncertainty components are incorporated.NOTE 2 The para
46、meter may be, for example, a standard deviation called standard measurement uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability.2 ISO 2012 All rights reservedBS ISO 22514-7:2012ISO 22514-7:2012(E)NOTE 3 Measurement uncertainty comprises
47、, in general, many components. Some of these may be evaluated by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity values from series of measurements and can be characterized by standard deviations. The other components, which may be evaluated by Type B e
48、valuation of measurement uncertainty, can also be characterized by standard deviations, evaluated from probability density functions based on experience or other information.NOTE 4 In general, for a given set of information, it is understood that the measurement uncertainty is associated with a stat
49、ed quantity value attributed to the measurand (3.2). A modification of this value results in a modification of the associated uncertainty.ISO/IEC Guide 99:2007, 2.263.4Type A evaluation of measurement uncertaintyType A evaluationevaluation of a component of measurement uncertainty (3.3) by statistical analysis of measurement quantity values obtained under defined measurement conditionsNOTE 1 For various types of measurement conditions, see repeatability condition of measurement, intermediate precision condit
