ASTM E2234-2009(2013) Standard Practice for Sampling a Stream of Product by Attributes Indexed by AQL《按AQL索引的属性对产品流进行取样的标准实施规程》.pdf

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1、Designation: E2234 09 (Reapproved 2013) 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 byAQL.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 supported by ASTM. Most of

4、the original text inMIL-STD-105E is preserved in Sections 4-6 of 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 of this standard to establ

5、ish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E456 Terminology Relating to Quality and StatisticsE1994 Practice for Use of Process Oriented AOQL andLTPD Sampling PlansE2586 Practice for

6、Calculating and Using Basic Statistics2.2 Other Standard:MIL-STD-105E Sampling Procedures and Tables for In-spection by Attributes33. Terminology3.1 Definitions:3.1.1 For a more extensive list of terms in E11 standards,see Terminology E456.3.1.2 acceptance quality limit (AQL), nquality limit that is

7、the worst tolerable process average when a continuing series oflots is submitted for acceptance sampling.3.1.2.1 DiscussionThis definition supersedes that given inMIL-STD-105E.3.1.3 average outgoing quality (AOQ), nthe average per-cent defective of outgoing product including all accepted lotsor batc

8、hes 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.E19943.1.4 average outgoing quality limit (AOQL), nthe AOQLis th

9、e maximum of the AOQs for all possible incomingpercentages defective for the process for a given acceptancesampling plan. E19943.1.5 classification of defects, nthe enumeration of pos-sible defects of the unit of product classified according to theirseriousness, that is, critical, major, or minor de

10、fect.3.1.6 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 islikely to prevent performance of the function of a major en

11、ditem.3.1.7 defect, nany nonconformance of the unit of productwith specified requirements.3.1.8 double sampling plan, na multiple sampling plan inwhich up to two samplings can be taken and evaluated toaccept or reject a lot.3.1.9 inspection, nthe process of measuring, examining,testing, or otherwise

12、 comparing the unit of product with therequirements.3.1.10 inspection by attributes, ninspection whereby ei-ther the unit of product is classified simply as defective ornon-defective, or the number of defects in the unit of productis counted, with respect to a given requirement or set ofrequirements

13、.3.1.11 inspection lot, na collection of units of productproduced under conditions that are considered uniform andfrom which a sample is drawn and inspected.1This practice is under the jurisdiction of ASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.30

14、 on StatisticalQuality Control.Current edition approved April 1, 2013. Published April 2013. Originallyapproved in 2005. Last previous edition approved in 2009 as E2234 09. DOI:10.1520/E2234-09R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a

15、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Bar

16、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.12 major defect, na defect, other than critical, that islikely to result in failure, or to reduce materially the usabilityof the unit of product for its intended purpose.3.1.13 minor defect, na defect that is not likely

17、 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.3.1.14 multiple sampling plan, na sampling plan in whichsuccessive samples from a lot are drawn and after

18、 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.3.1.14.1 DiscussionWhen the quality is much less ormuch more than theAQL, the decision can be made on the firstsample, which is smaller than that of

19、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 sampling plan.3.1.15 operating characteristic, nprobability of accep-tance using a speci

20、fied acceptance sampling plan, as a functionof parameters describing quality of the lot.3.1.16 sample, na group of observations, test results,taken from a large collection of observations, test results,which serves to provide information that may be used as a basisfor making a decision concerning th

21、e larger collection. E25863.1.16.1 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 units of product in the sample is thesample size.3.2 Definitions of Terms Specific

22、 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 units designated as a batch for otherpurposes, for example, production, shipment, et

23、c.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 and/orminor defects.3.2.4 defective, na unit of product which contains one ormore defects.3.2.5 defects per hundred units,

24、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 is:Defects per hundred units 5Number of defects 3100Number of units inspected(1)3.2.6 lot

25、, 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 defective, na unit of product which containsone or more minor defects but contains no critical

26、 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:Percent Defective 5Number of defectives 3100Number of units inspected(2)3.2.11 process

27、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 DiscussionOriginal inspection is the first inspec-tion of a particular quantity of product as distingu

28、ished 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 sampling plan (in inspection), na plan that indi-cates the number of units of product f

29、rom 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 product, nthat which is inspected in order todetermine its classification as defective or non-

30、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 of product mayor may not be the same as the unit of purchase, supply,production, or shi

31、pment.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 any contractual requirements. The words “accept,”“acceptance,” “acceptable,” etc, refer

32、 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 ofacceptability by the customer shall be as described in contrac-tual documents. The sampling plans d

33、escribed in this standardare applicable to AQLs of 0.01 percent or higher and aretherefore not suitable for applications where quality levels inthe range of parts per million levels can be realized.4.2 ApplicationSampling plans designated in this publi-cation are applicable, but not limited, to insp

34、ection 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)administrative procedures. These plans are intended primarilyto be used for a continuing series of

35、 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 theE2234 09 (2013)2operating characteristic curves to find a plan which will yieldthe desired protection (see 6.11).5. Definitions5.1 Acceptable Quali

36、ty 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 and an AQL are chosen in accor-dance with the risk assumed. Use of a value of AQL fo

37、r 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 lots or batches be no greaterthan the designated value of AQL. Thus, the AQL is ad

38、esignated 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 probability of acceptance at the designated AQL valuedepends upon the sample size,

39、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 beexpected from a series of lots or batches, provided the stepsindicated in this publ

40、ication 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 quality of outgoingproduct including all accepted lots or batches, plus all rejectedlo

41、ts or batches after the rejected lots or batches have beeneffectively 100 percent inspected and all defectives replaced bynon-defectives.5.3 Average Outgoing Quality Limit (AOQL)The AOQLis the maximum AOQ for a given acceptance sampling plan.Factors for computingAOQL values are given in Table V-Afor

42、each 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 Defects A classification of defects isthe enumeration of possible defects of the unit of productclassified according to their seriousness5.5 Cri

43、tical 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 andexperience indicate is likely to prevent performance of thetactical function

44、 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 and/or minor defects.5.7 Defect.A defect is any nonconformance of the unit ofproduct with

45、 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 onehundred times the number of defects contained therein (one ormore defects being

46、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,examining, testing, or otherwise comparing the unit of productwith the requirements

47、.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

48、 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 differ from a collection of units designatedas a lot or batch for other purposes (for example, production,shipment, etc.).5.13 Lot or Batch Siz

49、eThe lot or batch size is the numberof units of product in a lot or batch.5.14 Major DefectA major defect is a defect, other thancritical, that is likely to result in failure, or to reduce materiallythe usability of the unit of product for its intended purpose.5.15 Major DefectiveA major defective is a unit of prod-uct which contains one or more major defects, and may alsocontain minor defects but contains no critical defect.5.16 Minor DefectA minor defect is a defect that is notlikely to reduce materially the usability of the