1、BRITISH STANDARD BS 6001-3:2005 ISO 2859-3:2005 Sampling procedures for inspection by attributes Part 3: Skip-lot sampling procedures ICS 03.120.30 BS 6001-3:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 23 June 2005 BSI 23 June 2005 I
2、SBN 0 580 46214 5 National foreword This British Standard reproduces verbatim ISO 2859-3:2005 and implements it as the UK national standard. It supersedes BS 6001-3:1993 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee SS/5, Acceptance sampling schemes
3、, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section ent
4、itled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Complian
5、ce with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related intern
6、ational and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 29 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last
7、 issued. Amendments issued since publication Amd. No. Date CommentsReference number ISO 2859-3:2005(E) INTERNATIONAL STANDARD ISO 2859-3 Second edition 2005-05-01 Sampling procedures for inspection by attributes Part 3: Skip-lot sampling procedures Rgles dchantillonnage pour les contrles par attribu
8、ts Partie 3: Procdures dchantillonnage successif partiel ISO 2859-3:2005ii ISO 2859-3:2005iii Contents Page Foreword iv 1 Scope 1 2 Normative references . 1 3 Terms, definitions and symbols 1 3.1 Terms and definitions. 1 3.2 Symbols and abbreviated terms 3 4 General requirements . 3 5 Supplier and p
9、roduct qualification 4 5.1 Supplier qualification 4 5.2 Product qualification 5 5.3 Qualification score 6 5.4 Example for product qualification. 8 6 Skip-lot sampling procedures . 9 6.1 General. 9 6.2 Initial inspection frequency and its determination 11 6.3 Inspection frequency and shifting 11 6.4
10、Sampling plans, lot selection and inspection procedures (States 2 and 3) . 14 6.5 Skip-lot interruption 15 6.6 Requalification 16 6.7 Product disqualification . 16 6.8 Supplier disqualification and suspension 17 7 Supplier responsibilities 17 8 Inspection agency and responsible authority responsibil
11、ities 18 8.1 General. 18 8.2 Responsibilities on supplier qualification 19 8.3 Other responsibilities . 19 9 Compatibility with ISO 2859-1 20 9.1 Limitations . 20 9.2 Relation to reduced inspection . 20 10 Additional information 21 10.1 Design basis 21 10.2 Statistical characteristics of the skip-lo
12、t procedures . 21 Annex A (normative) Optional requirements to be agreed prior to product qualification 23 Annex B (normative) Procedures for random selection at specified inspection frequency 25 Annex C (informative) Factors used in deciding between skip-lot inspection and reduced inspection 27 Bib
13、liography . 29 ISO 2859-3:2005iv 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 inte
14、rested 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 Electrotechnica
15、l 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 t
16、echnical 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. I
17、SO shall not be held responsible for identifying any or all such patent rights. ISO 2859-3 was prepared by Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 5, Acceptance sampling. This second edition cancels and replaces the first edition (ISO 2859-3:1991), which h
18、as been technically revised. ISO 2859 consists of the following parts, under the general title Sampling procedures for inspection by attributes: Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection Part 2: Sampling plans indexed by limiting quality (LQ) for is
19、olated lot inspection Part 3: Skip-lot sampling procedures Part 4: Procedures for assessment of declared quality levels Part 5: System of sequential sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection. Part 10: Overview of the ISO 2859 attribute sampling systems ISO 28
20、59-3:2005 1 Sampling procedures for inspection by attributes Part 3: Skip-lot sampling procedures 1 Scope This part of ISO 2859 specifies generic skip-lot sampling procedures for acceptance inspection by attributes. The purpose of these procedures is to provide a way of reducing the inspection effor
21、t on products of high quality submitted by a supplier who has a satisfactory quality assurance system and effective quality controls. The reduction in inspection effort is achieved by determining at random, with a specified probability, whether a lot presented for inspection will be accepted without
22、 inspection. This procedure extends the principle of the random selection of sample items already applied in ISO 2859-1 to the random selection of lots. The skip-lot sampling procedures specified in this part of ISO 2859 are applicable to, but not limited to, inspection of a) end items, such as comp
23、lete products or sub-assemblies, b) components and raw materials, and c) materials in process. 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 ed
24、ition of the referenced document (including any amendments) applies. ISO 2859-1:1999, Sampling procedures for inspection by attributes Part 1:Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection ISO 3534-1, Statistics Vocabulary and symbols Part 1: Probability and gen
25、eral statistical terms ISO 3534-2, Statistics Vocabulary and symbols Part 2: Applied statistics 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 2859-1, ISO 3534-1, ISO 3534-2 and the following apply. For ease of ref
26、erence, some terms are quoted from these standards. 3.1.1 continuous production production that is at a steady rate NOTE Production is considered continuous if the production has been continued for a specified production period at a specified production frequency (see 5.2.1). Continuous production i
27、s considered a stabilizing factor of the manufacturing or assembly processes. ISO 2859-3:20052 3.1.2 disqualification failure to qualify for skip-lot sampling inspection (3.1.11) 3.1.3 inspection agency independent third party with the responsibility for lot inspection and qualification assessment 3
28、.1.4 inspection frequency probability that a lot is inspected NOTE Inspection frequencies specified in this part of ISO 2859 are 1/2,1/3,1/4 and 1/5. 3.1.5 interruption cessation of skip-lot sampling inspection (3.1.11), ending with a return either to skip-lot sampling inspection or to lot-by-lot in
29、spection 3.1.6 lot-by-lot inspection inspection of products submitted in a series of lots NOTE 1 In this part of ISO 2859, a sample (or samples) is (are) drawn from each lot and inspected using acceptance sampling procedures by attributes given in ISO 2859-1. NOTE 2 In this part of ISO 2859, lot-by-
30、lot inspection is used both in State 1 (qualification period) and State 3 (skip-lot interruption state) (see 5.1). 3.1.7 product qualification assessment of the product to determine its suitability for skip-lot sampling inspection (3.1.11) 3.1.8 qualification score running total derived according to
31、 given rules from the immediately preceding quality history, and used in making decisions regarding qualification, changes in inspection frequency (3.1.4), interruption (3.1.5), disqualification (3.1.2) and requalification (3.1.9) 3.1.9 requalification qualification for a resumption of skip-lot samp
32、ling inspection (3.1.11) 3.1.10 responsible authority person or group of people who has responsibility and authority to manage inspection systems appropriately NOTE In this part of ISO 2859, the responsible authority has responsibility and authority to assess and verify supplier qualification, decid
33、e various criteria and judge switch inspection stages. 3.1.11 skip-lot sampling inspection sampling inspection procedure in which some lots in a series are accepted without inspection when the sampling results for a stated number of immediately preceding lots meet stated criteria NOTE The lots to be
34、 inspected are chosen randomly in accordance with a stated (skip-lot) inspection frequency. An inspection frequency of 1 in 2, for example, means that the long run average proportion of lots inspected is 1/2. ISO 2859-3:2005 3 3.1.12 supplier qualification assessment of the suppliers competence to i
35、mplement skip-lot sampling inspection (3.1.11) 3.2 Symbols and abbreviated terms The symbols and abbreviated terms used in this document are as follows: Ac acceptance number; Ac 0 acceptance number for the corresponding single sampling plan; Ac 1first acceptance number (for the double or multiple sa
36、mpling plan); Ac 2second acceptance number (for the double or multiple sampling plan); d number of nonconforming items or nonconformities in the sample; k number of lots used for inspection frequency (the inspection frequency is 1 in k; i.e. 1/k); n sample size. 4 General requirements 4.1 Skip-lot i
37、nspection may only be used when both the supplier and the product are qualified. The requirements for qualification are specified in Clause 5. NOTE The skip-lot sampling procedures specified in this part of ISO 2859 should be distinguished from Dodges skip-lot sampling plans. See 1, 2 and 3 in the B
38、ibliography. 4.2 This part of ISO 2859 is intended to supplement the ISO 2859-1 sampling system, and may be used together with ISO 2859-1. Unless otherwise specified in this part of ISO 2859, the provisions of ISO 2859-1 shall apply. ISO 2859-10 provides useful information concerning the use of the
39、standards in the ISO 2859 series. 4.3 The skip-lot sampling procedures specified in this part of ISO 2859 are intended only for a continuing series of lots and shall not be used for isolated lots. All lots in the series are expected to be of a similar quality and there should be reason to believe th
40、at lots not inspected are of the same quality as the ones inspected. 4.4 Skip-lot sampling may be used instead of reduced inspection if it is more cost effective to do so (see 9.2 and Annex C), but its application and switching rules are different from those of reduced inspection in ISO 2859-1. 4.5
41、There are some limitations to the use of skip-lot sampling procedures (see 9.1). 4.6 When different acceptance quality limit (AQL) values are specified for two or more classes of nonconforming items or nonconformities, special care should be taken to ensure correct application of the standard (see 5
42、.2.2 to 6.6 and 10.2). 4.7 Inspection may take place at the suppliers or purchasers locations, or at an interface between operations of a production process. 4.8 As every product has its own environment and characteristics, options are provided so that the supplier and the responsible authority may
43、select the appropriate options to meet the specifics of the product and its environment. All choices as a result of this tailoring should be specified in a written document. 4.9 When specified by the purchaser, this part of ISO 2859 may be referenced in a purchasing or specification contract, inspec
44、tion instruction, or other contractual documents. ISO 2859-3:20054 4.10 The responsible authority and the inspection agency are to be designated in one of the above documents. This part of ISO 2859 assumes that both lot inspection and qualification assessment are conducted by an inspection agency, b
45、eing an independent third party. However, the purchaser may conduct both. It is necessary to replace the term “inspection agency” by “purchasers inspector” or “assessing team” as occasion demands (see 5.1.2, 5.2.3 and Clauses 7 and 8). 5 Supplier and product qualification 5.1 Supplier qualification
46、5.1.1 Requirements for supplier qualification The requirements for supplier qualification are as follows. a) The supplier shall have implemented and maintained a documented system for controlling product quality and design changes. It is assumed that the system includes inspection by the supplier of
47、 each lot produced and the recording of inspection results. b) The supplier shall have instituted a system that is capable of detecting and correcting shifts in quality levels and monitoring process changes that may adversely affect quality. The suppliers personnel responsible for the application of
48、 the system shall demonstrate a clear understanding of the applicable standards, systems and procedures to be followed. c) The supplier shall not have experienced any change that might adversely affect quality. 5.1.2 Assessment for supplier qualification An assessment team may be dispatched for the
49、assessment for supplier qualification. When the assessment is conducted by the inspection agency, a typical example of what is to be examined and how functions and responsibilities are shared is shown in Clause 8. When the purchaser conducts the assessment for supplier qualification, the functions and responsibilities of the assessment team are similar to those of the inspection agency. If the supplier has been qualified for anothe
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