1、Designation: E2234 09An 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 the case of revisi
2、on, 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 standard establishes lot or batch sampling plansand procedures for inspection by attributes using
3、 MIL-STD-105E as a basis for sampling a steady stream of lots indexed byAQL.1.2 This standard 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-105 inindustries supported by ASTM. Most of the original text i
4、nMIL-STD-105E is preserved in Sections4-6ofthis standard.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 establish appro-priate safet
5、y 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 Calculating and Using
6、Basic Statistics2.2 Other Standard:MIL-STD-105E Sampling Procedures and Tables for In-spection by Attributes33. Terminology3.1 Definitions: E1994Terminology For a more extensivelist of terms in E11 standards see Terminology E456.3.1.1 acceptance quality limit (AQL), nquality limit thatis the worst t
7、olerable process average when a continuing seriesof lots 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 defective of outgoing product including all accepted lotsor batches after a
8、ny 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.E19943.1.3 average outgoing quality limit (AOQL), nthe AOQLis the maximum o
9、f 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 to theirseriousness, that is, critical, major, or minor defect.3.1.5
10、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 enditem.3.1.6
11、 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.3.1.8 inspection, nthe process of measuring, examining,testing, or otherwise comparing
12、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-ments.3.1.10 ins
13、pection 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 on Statist
14、icalQuality Control.Current edition approved Nov. 1, 2009. Published December 2009. Originallyapproved in 2005. Last previous edition approved in 2008 as E223408. DOI:10.1520/E2234-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm
15、.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.1Copyright ASTM International, 100 Barr Harbor Dri
16、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 product for its intended purpose.3.1.12 minor defect, na defect that is not likely to reducema
17、terially 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 sampling plan, na sampling plan in whichsuccessive samples from a lot are drawn and after each sample
18、is 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 the AQL, the decision can be made on the firstsample, which is smaller than that of a single sa
19、mpling planwith equivalent acceptance quality level. For samples that areclose to the AQL in quality, additional samples are required andthe total sample size will be larger than the correspondingsingle sampling plan.3.1.14 operating characteristic, nprobability of accep-tance using a specified acce
20、ptance 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 provide information that may be used as a basisfor making a decision concerning the larger
21、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 units of product in the sample is thesample size.3.2 Definitions of Terms Specific to This S
22、tandard: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, etc.3.2.2 ba
23、tch 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, nany given
24、 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, nsee bat
25、ch.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 or majord
26、efect.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 3 100Number of units inspected(2)3.2.11 process average (
27、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 distinguished fro
28、mthe 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 from each
29、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-defective
30、 or tocount the number of defects.3.2.14.1 Discussion It 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 shipment.4.
31、 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 9accept9, 9accep-tance”, “acceptable”, etc, refer only
32、to the contractors use ofthe sampling plans contained in this standard and do not implyan agreement by the customer (formerly “Government” inoriginal text) to accept any product. Determination of accept-ability by the customer shall be as described in contractualdocuments. The sampling plans describ
33、ed in this standard areapplicable to AQLs of 0.01 percent or higher and are thereforenot suitable for applications where quality levels in the range ofparts per million levels can be realized.4.2 ApplicationSampling plans designated in this publi-cation are applicable, but not limited, to inspection
34、 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 lots
35、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 092operating characteristic curves to find a plan which will yieldthe desired protection (see 6.11).5. Definitions5.1 Acceptable Quality Level (AQL
36、)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 for acertain de
37、fect 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 adesignated val
38、ue 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, being general
39、ly 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 publication are t
40、aken. 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 rejectedlots or batches
41、 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 computing AOQL values are given in Table V-A foreach of the
42、 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 Critical Defec
43、tA 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 of a major
44、 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 specified
45、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 possible in
46、 any unit of product) divided bythe total number of units of product, i.e.:Defects per hundred units 5Number of defects x 100/Number of units inspected5.10 InspectionInspection is the process of measuring,examining, testing, or otherwise comparing the unit of productwith the requirements.5.11 Inspec
47、tion 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 sh
48、all mean“inspection lot” or “inspection batch”, i.e., a collection of unitsof product from which a sample is to be drawn and inspectedand may differ from a collection of units designated as a lot orbatch for other purposes (e.g., production, shipment, etc.).5.13 Lot or Batch SizeThe lot or batch siz
49、e 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 ofproduct which contains one or more major defects, and mayalso contain 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 unit of productfor its i
