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1、 Reference number ISO 22514-3:2008(E) ISO 2008 INTERNATIONAL STANDARD ISO 22514-3 First edition 2008-02-15 Statistical methods in process management Capability and performance Part 3: Machine performance studies for measured data on discrete parts Mthodes statistiques dans la gestion de processus Ap
2、titude et performance Partie 3: tudes de performance de machines pour des donnes mesures sur des parties discrtes Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or ne
3、tworking permitted without license from IHS -,-,- ISO 22514-3:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and instal
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6、ease inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 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
7、, without permission in writing from either ISO at the address below or ISOs 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 copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 A
8、ll rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22514-3:2008(E) ISO 2008 All rights reser
9、ved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Symbols and abbreviations. 1 3 Pre-conditions for application. 2 4 Data collection 3 5 Analysis . 4 6 Reporting. 14 7 Actions following a machine performance study 16 Annex A (informative) Tables and worksheets . 17 Annex B (informative)
10、 Computer analysis of data 20 Bibliography. 23 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22514-3:2008(
11、E) iv ISO 2008 All rights reserved 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 in
12、terested 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 Electrotechni
13、cal 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
14、 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.
15、 ISO shall not be held responsible for identifying any or all such patent rights. ISO 22514-3 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, u
16、nder the general title Statistical methods in process management Capability and performance: Part 1: General principles and concepts Part 3: Machine performance studies for measured data on discrete parts Part 4: Process capability estimates and performance measures Technical Report In the future, i
17、t is planned to revise ISO 21747:2006 (Statistical methods Process performance and capability statistics for measured quality characteristics) as Part 2. NOTE ISO 22514-3 was initially prepared as ISO/DIS 13700. It was renumbered before publication to include it in the ISO 22514 series. Copyright In
18、ternational Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22514-3:2008(E) ISO 2008 All rights reserved v Introduction This part of
19、 ISO 22514 has been prepared to provide guidance in circumstances where a study is necessary to determine if the output from a machine, for example, is acceptable according to some criteria. Such circumstances are common in engineering when the purpose for the study is part of an acceptance trial. T
20、hese studies may also be used when diagnosis is required concerning a machines current level of performance or as part of a problem solving effort. The method is very versatile and has been applied to many situations. Machine performance studies of this type provide information about the behaviour o
21、f a machine under very restricted conditions such as limiting, as far as possible, external sources of variation that are commonplace within a process, e.g. multi-factor and multi-level situations. The data gathered in a study might come from items made consecutively, although this may be altered ac
22、cording to the study requirements. The data are assumed to have been, generally, gathered manually. The study procedure and reporting will be of interest to engineers, supervisors and management wishing to establish whether a machine should be purchased or put in for maintenance, to assist in proble
23、m solving or to understand the level of variation due to the machine itself. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networking permitted without license fr
24、om IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 22514-3:2008(E) ISO 2008
25、 All rights reserved 1 Statistical methods in process management Capability and performance Part 3: Machine performance studies for measured data on discrete parts 1 Scope This part of ISO 22514 prescribes the steps to be taken in conducting short-term performance studies that are typically performe
26、d on machines where parts produced consecutively under repeatability conditions are considered. The number of observations to be analysed will vary according to the patterns the data produce, or if the runs (the rate at which items are produced) on the machine are low in quantity. The methods are no
27、t recommended where the sample size produced is less than 30 observations. Methods to be used for handling the data and carrying out the calculations are described. In addition, machine performance indices and the actions required at the conclusion of a machine performance study are described. The d
28、ocument is not applicable when tool wear patterns are expected to be present during the duration of the study, nor if autocorrelation between observations is present. The situation where a machine has captured the data, sometimes thousands of data points collected in a minute, is not considered suit
29、able for the application of this part of ISO 22514. 2 Symbols and abbreviations Pm machine performance index Pmk minimum machine performance index PmkL lower machine performance index PmkU upper machine performance index f frequency f cumulative frequency i subscript used to identify values of a var
30、iable L lower specification limit N total sample size X % % distribution fractile Xi ith value in a sample Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo reproduction or networkin
31、g permitted without license from IHS -,-,- ISO 22514-3:2008(E) 2 ISO 2008 All rights reserved standard deviation, population S standard deviation, sample statistic, () 2 1 1 N i i XX S N = = U upper specification limit z fractile of the standardized normal distribution from to population mean value
32、in relation to the machine location X arithmetic mean value, sample, 1 N i i X X N = = GRR gauge repeatability and reproducibility 2 fractile of the Chi-square distribution 3 Pre-conditions for application 3.1 General The pre-conditions given below are the minimum and may be exceeded when needed. In
33、 this type of study, it is important to maintain constant all factors, other than the machine, which will influence the results, if the study is to properly represent the machine itself, e.g. the same operator, same batch of material, etc. 3.2 Number of parts to be used in the study The number speci
34、fied will usually be 100. However, if the pattern of variation is expected to form a non-normal distribution, the number of parts should be at least 100. The methods given within this part of ISO 22514 may also be used when conducting audits of a process, in which case the number of measurements tak
35、en might be less than the above number, e.g. 50. NOTE 1 This is to ensure that a reasonably narrow confidence interval can be calculated for the machine performance indices when a normal distribution has been used. The interval will be approximately 12 % of the estimated index with a confidence of 9
36、0 % for samples of 100. Some machines have very slow cycle times and a “run” cannot produce 100 parts. In such circumstances, it will be necessary to proceed with available data. The minimum number that this part of ISO 22514 recommends with the methods described herein is 30. NOTE 2 Special techniq
37、ues beyond the scope of this part of ISO 22514 exist for circumstances when there are fewer samples. By contrast, a machine that produces parts at a very high rate, e.g. a rivet-making machine, the sampling strategy may require alteration since 100 parts will be produced in a few seconds. In circums
38、tances such as these, several studies may be required each allowing a different sampling approach to examine the machines behaviour. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:21:24 MDTNo
39、 reproduction or networking permitted without license from IHS -,-,- ISO 22514-3:2008(E) ISO 2008 All rights reserved 3 3.3 Materials to be used Ensure all input materials to be used in the study have been checked, conform to specifications and belong to the same batches. It is not advised that a st
40、udy be conducted with materials that are outside specification since this could lead to unrepresentative results. Care should be exercised not to introduce any other sources of variation other than those to be studied. A typical example is where a machine run has to change to another batch of a part
41、icular material within a single process batch, and batch material variation is not included in the study. In this instance, only data taken while the first batch of that particular material was in use should be used in the analysis. 3.4 Measurement system Ensure the measurement system to be used dur
42、ing the study has adequate properties, is calibrated and the measurement system variation has been quantified and minimized. Special studies on the measurement system should be undertaken to establish the amount of variation present due to measuring. The measurement system should ideally have a comb
43、ined gauge repeatability and reproducibility (GRR) of less than 10 % of the process spread of the characteristic that the machine study is to investigate as determined through a properly conducted measurement system analysis. This analysis should address issues of bias, stability, linearity and disc
44、rimination, as well as GRR. It may be appropriate to express the GRR as a percentage of a given specification tolerance. If the measurement system has between 10 % and 30 % GRR, it may still be regarded as acceptable dependant upon application. If it exceeds 30 %, the measurement system should be re
45、garded as inappropriate. In addition, the measurement system should have a measurement uncertainty appreciably less than the tolerance or of the expected total variation of the characteristic, if known, as indicated above. Should a study be performed using a measurement system with a performance wor
46、se than these requirements, some erroneous conclusions to the study might be reached. 3.5 Running the study Ensure an uninterrupted run takes place, under normal operating conditions. This will include any warm-up time for the machine necessary to bring it up to its usual operating condition and wit
47、h the machine set at nominal for the characteristic to be studied. If the machine is stopped during the study for whatever reason, either re-run the study again or analyse the data collected, as long as sufficient data has been collected and as long as the repeatability conditions have not been viol
48、ated. Under no circumstance should less than 30 results be used. 3.6 Special circumstances In a multiple fixture set-up, multiple-cavity or multi-stream situation, each station, fixture, cavity or stream should be treated as a separate machine for machine performance purposes since those streams may violate the repeatability conditions. In the case of a multiple-cavity tool, some extra studies may be performed to examine the between-cavit