ASTM E2234-2009(2018) Standard Practice for Sampling a Stream of Product by Attributes Indexed by AQL.pdf

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1、Designation: E2234 09 (Reapproved 2018) An American National StandardStandard Practice forSampling a Stream of Product by Attributes Indexed byAQL1This standard is issued under the fixed designation E2234; the number immediately following the designation indicates the year oforiginal adoption or, in

2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice establishes lot or batch sampling plans andprocedures for inspection

3、by attributes using MIL-STD-105Eas a basis for sampling a steady stream of lots indexed byacceptance quality limit (AQL).1.2 This practice provides the sampling plans of MIL-STD-105E in ASTM format for use by ASTM committees andothers. It recognizes the continuing usage of MIL-STD-105Ein industries

4、supported by ASTM. Most of the original text inMIL-STD-105E is preserved in Sections 46of this practice.1.3 No system of units is specified in this standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o

5、f this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the

6、 Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E456 Terminology Relating to Quality and StatisticsE1994 Practice for Use of

7、 Process Oriented AOQL andLTPD Sampling PlansE2586 Practice for Calculating and Using Basic Statistics2.2 Other Standard:MIL-STD-105E Sampling Procedures and Tables for In-spection by Attributes33. Terminology3.1 DefinitionsFor a more extensive list of terms in E11standards, see Terminology E456.3.1

8、.1 acceptance quality limit (AQL), nquality limit that isthe worst tolerable process average when a continuing series oflots is submitted for acceptance sampling.3.1.1.1 DiscussionThis definition supersedes that given inMIL-STD-105E.3.1.2 average outgoing quality (AOQ), nthe average per-cent defecti

9、ve of outgoing product including all accepted lotsor batches after any defectives found in them are replaced byacceptable units, plus all lots or batches which are not acceptedafter such lots or batches have been effectively 100 %inspected and all defective units replaced by acceptable units.E19943.

10、1.3 average outgoing quality limit (AOQL), nthe AOQLis the maximum of the AOQs for all possible incomingpercentages defective for the process for a given acceptancesampling plan. E19943.1.4 classification of defects, nthe enumeration of pos-sible defects of the unit of product classified according t

11、o theirseriousness, that is, critical, major, or minor defect.3.1.5 critical defect, na defect that judgment and experi-ence indicate would result in hazardous or unsafe conditionsfor individuals using, maintaining, or depending upon theproduct, or a defect that judgment and experience indicate isli

12、kely to prevent performance of the function of a major enditem.3.1.6 defect, nany nonconformance of the unit of productwith specified requirements.3.1.7 double sampling plan, na multiple sampling plan inwhich up to two samplings can be taken and evaluated toaccept or reject a lot.1This practice is u

13、nder the jurisdiction of ASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.30 on StatisticalQuality Control.Current edition approved Sept. 1, 2018. Published October 2018. Originallyapproved in 2005. Last previous edition approved in 2013 as E2234 09 (2

14、013).DOI: 10.1520/E2234-09R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Nation

15、al Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized pri

16、nciples on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.8 inspection, nthe process of measuring, examining,testing, or otherw

17、ise comparing the unit of product with therequirements.3.1.9 inspection by attributes, ninspection whereby eitherthe unit of product is classified simply as defective or non-defective, or the number of defects in the unit of product iscounted, with respect to a given requirement or set of require-me

18、nts.3.1.10 inspection lot, na collection of units of productproduced under conditions that are considered uniform andfrom which a sample is drawn and inspected.3.1.11 major defect, na defect, other than critical, that islikely to result in failure, or to reduce materially the usabilityof the unit of

19、 product for its intended purpose.3.1.12 minor defect, na defect that is not likely to reducematerially the usability of the unit of product for its intendedpurpose, or is a departure from established standards havinglittle bearing on the effective use or operation of the unit.3.1.13 multiple sampli

20、ng plan, na sampling plan in whichsuccessive samples from a lot are drawn and after each sampleis inspected a decision is made to accept the lot, reject the lot,or to take another sample, based on quality level of thecombined samples.3.1.13.1 DiscussionWhen the quality is much less ormuch more than

21、theAQL, the decision can be made on the firstsample, which is smaller than that of a single sampling planwith equivalent acceptance quality level. For samples that areclose to theAQLin quality, additional samples are required andthe total sample size will be larger than the correspondingsingle sampl

22、ing plan.3.1.14 operating characteristic, nprobability of accep-tance using a specified acceptance sampling plan, as a functionof parameters describing quality of the lot.3.1.15 sample, na group of observations, test results,taken from a large collection of observations, test results,which serves to

23、 provide information that may be used as a basisfor making a decision concerning the larger collection. E25863.1.15.1 DiscussionA sample consists of one or moreunits of product drawn from an inspection lot, the units of thesample being selected at random without regard to theirquality. The number of

24、 units of product in the sample is thesample size.3.2 Definitions of Terms Specific to This Standard:3.2.1 batch (in inspection), na collection of units ofproduct produced under conditions that are considered uniformand from which a sample is drawn and inspected, and maydiffer from a collection of u

25、nits designated as a batch for otherpurposes, for example, production, shipment, etc.3.2.2 batch size, nthe number of units of product in abatch.3.2.3 critical defective, na unit of product which containsone or more critical defects and may also contain major orminor defects, or both.3.2.4 defective

26、, na unit of product which contains one ormore defects.3.2.5 defects per hundred units, nany given quantity ofunits of product is one hundred times the number of defectscontained therein (one or more defects being possible in anyunit of product) divided by the total number of units of product,that i

27、s:Defects per hundred units 5Number of defects 3100Number of units inspected(1)3.2.6 lot, nsee batch.3.2.7 lot size, nsee batch size.3.2.8 major defective, na unit of product which containsone or more major defects, and may also contain minor defectsbut contains no critical defect.3.2.9 minor defect

28、ive, na unit of product which containsone or more minor defects but contains no critical or majordefect.3.2.10 percent defective, nany given quantity of units ofproduct one hundred times the number of defective units ofproduct contained therein divided by the total number of unitsof product, that is

29、:Percent Defective 5Number of defectives 3100Number of units inspected(2)3.2.11 process average (in inspection), nthe average per-cent defective or average number of defects per hundred units(whichever is applicable) of product submitted by the supplierfor original inspection.3.2.11.1 DiscussionOrig

30、inal inspection is the first inspec-tion of a particular quantity of product as distinguished fromthe inspection of product which has been resubmitted afterprior rejection.3.2.12 sample size code letter, na device used along withthe AQL for locating a sampling plan on a table of samplingplans.3.2.13

31、 sampling plan (in inspection), na plan that indi-cates the number of units of product from each lot or batchwhich are to be inspected (sample size or series of samplesizes) and the criteria for determining the acceptability of thelot or batch (acceptance and rejection numbers).3.2.14 unit of produc

32、t, nthat which is inspected in order todetermine its classification as defective or non-defective or tocount the number of defects.3.2.14.1 DiscussionIt may be a single article, a pair, a set,a length, an area, an operation, a volume, a component of anend product, or the end product itself. The unit

33、 of product mayor may not be the same as the unit of purchase, supply,production, or shipment.4. Significance and Use4.1 PurposeThis publication establishes lot or batch sam-pling plans and procedures for inspection by attributes. Thispublication shall not be interpreted to supersede or conflictwith

34、 any contractual requirements. The words “accept,”“acceptance,” “acceptable,” etc, refer only to the contractorsuse of the sampling plans contained in this standard and do notimply an agreement by the customer (formerly “Government”in original text) to accept any product. Determination ofE2234 09 (2

35、018)2acceptability by the customer shall be as described in contrac-tual documents. The sampling plans described in this standardare applicable to AQLs of 0.01 % or higher and are thereforenot suitable for applications where quality levels in the range ofparts per million levels can be realized.4.2

36、ApplicationSampling plans designated in this publi-cation are applicable, but not limited, to inspection of thefollowing: (1) end items, (2) components and raw materials, (3)operations or services, (4) materials in process, (5) supplies instorage, (6) maintenance operations, (7) data or records, (8)

37、administrative procedures. These plans are intended primarilyto be used for a continuing series of lots or batches. The plansmay also be used for the inspection of isolated lots or batches,but, in this latter case, the user is cautioned to consult theoperating characteristic curves to find a plan wh

38、ich will yieldthe desired protection (see 6.11).5. Definitions5.1 Acceptable Quality Level (AQL)When a continuousseries of lots is considered, the AQL is the quality level which,for the purposes of sampling inspection, is the limit of asatisfactory process average (see 5.19).5.1.1 A sampling plan an

39、d an AQL are chosen in accor-dance with the risk assumed. Use of a value of AQL for acertain defect or group of defects indicates that the samplingplan will accept the great majority of the lots or batchesprovided the process average level of percent defective (ordefects per hundred units) in these

40、lots or batches be no greaterthan the designated value of AQL. Thus, the AQL is adesignated value of percent defective (or defects per hundredunits) for which lots will be accepted most of the time by thesampling procedure being used.5.1.2 The sampling plans provided herein are so arrangedthat the p

41、robability of acceptance at the designated AQL valuedepends upon the sample size, being generally higher for largesamples than for small ones, for a given AQL. The AQL alonedoes not identify the chances of accepting or rejecting indi-vidual lots or batches but more directly relates to what might bee

42、xpected from a series of lots or batches, provided the stepsindicated in this publication are taken. It is necessary to refer tothe operating characteristic curve of the plan to determine therelative risks.5.2 Average Outgoing Quality (AOQ)For a particularprocess average, the AOQ is the average qual

43、ity of outgoingproduct including all accepted lots or batches, plus all rejectedlots or batches after the rejected lots or batches have beeneffectively 100 % inspected and all defectives replaced bynon-defectives.5.3 Average Outgoing Quality Limit (AOQL)The AOQLis the maximum AOQ for a given accepta

44、nce sampling plan.Factors for computingAOQL values are given in Table V-Aforeach of the single sampling plans for normal inspection and inTable V-B for each of the single sampling plans for tightenedinspection.5.4 Classification of DefectsA classification of defects isthe enumeration of possible def

45、ects of the unit of productclassified according to their seriousness5.5 Critical DefectA critical defect is a defect that judg-ment and experience indicate would result in hazardous orunsafe conditions for individuals using, maintaining, or de-pending upon the product, or a defect that judgment ande

46、xperience indicate is likely to prevent performance of thetactical function of a major end item such as a ship, aircraft,tank, missile, or space vehicle.5.6 Critical DefectiveA critical defective is a unit ofproduct which contains one or more critical defects and mayalso contain major or minor defec

47、ts, or both.5.7 DefectA defect is any nonconformance of the unit ofproduct with specified requirements.5.8 DefectiveA defective is a unit of product whichcontains one or more defects.5.9 Defects per Hundred UnitsThe number of defects perhundred units of any given quantity of units of product is oneh

48、undred times the number of defects contained therein (one ormore defects being possible in any unit of product) divided bythe total number of units of product, that is:Defects per hundred units 5Number of defects 3100Number of units inspected5.10 InspectionInspection is the process of measuring,exam

49、ining, testing, or otherwise comparing the unit of productwith the requirements.5.11 Inspection by AttributesInspection by attributes isinspection whereby either the unit of product is classifiedsimply as defective or non-defective, or the number of defectsin the unit of product is counted, with respect to a givenrequirement or set of requirements.5.12 Lot or BatchThe term lot or batch shall mean“inspection lot” or “inspection batch”, that is, a collection ofunits of product from which a sample is to be drawn andinspected and may