1、Designation: E2819 11Standard Practice forSingle- and Multi-Level Continuous Sampling of a Stream ofProduct by Attributes Indexed by AQL1This standard is issued under the fixed designation E2819; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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 tables and procedures forapplying five different types of continuou
3、s sampling plans forinspection by attributes using MIL-STD-1235B as a basis forsampling a steady stream of lots indexed by AQL.1.2 This practice provides the sampling plans of MIL-STD-1235B in ASTM format for use by ASTM committees andothers. It recognizes the continuing usage of MIL-STD-1235Bin ind
4、ustries supported by ASTM. Most of the original text inMIL-STD-1235B is preserved in Sections 6-10 of this practice.1.3 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
5、 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 PlansE2234 Practice for Sampling a Strea
6、m of Product byAttributes Indexed by AQL2.2 Military Standards:3MIL-STD-1235A1 Functional Curves of the ContinuousSampling PlansMIL-STD-1235B Single- and Multi-Level ContinuousSampling for Attributes3. Terminology3.1 DefinitionsFor a more extensive list of terms in E11standards see Terminology E456.
7、3.1.1 acceptance quality limit (AQL), nquality limit thatis the worst tolerable process average when a continuing seriesof lots is submitted for acceptance sampling. E22343.1.2 average outgoing quality (AOQ), nthe average per-cent defective of outgoing product including all accepted lotsor batches a
8、fter 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 % in-spected and all defective units replaced by acceptable units.E19943.1.3 average outgoing quality limit (AOQL), nthe maxi-mum AOQ
9、 for a given acceptance sampling plan for allpossible incoming percentages defective for the process.E19943.1.4 continuous sampling inspection, na method of sam-pling a stream of product in order of production where thesampling frequency is adjusted based on ongoing inspectionresults.3.1.4.1 Discuss
10、ionOnly those units of product found bythe inspector or screening crew to be nonconforming arerejected. The rest of production, uninspected units as well asunits found to be conforming, is allowed to continue down theproduction line as conforming material.3.1.5 critical defect, na defect that judgme
11、nt 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. E22343.1.6 critical defective, na unit of
12、product which containsone or more critical defects and may also contain major andminor, or both, defects. E22343.1.7 defect, nany nonconformance of the unit of productwith specified requirements. E22343.1.8 inspection, nthe process of measuring, examining,testing, or otherwise comparing the unit of
13、product with therequirements. E22341This practice is under the jurisdiction of ASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.30 on StatisticalQuality Control.Current edition approved May 1, 2011. Published July 2011. DOI: 10.1520/E2819-11.2For refer
14、enced 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 Standardization Documents Order Desk, DODSSP, Bldg. 4,S
15、ection D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.9 inspection by attributes, ninspection whereby eitherthe unit of product is classified simply as
16、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. E22343.1.10 major defect, na defect, other than critical, that islikely to result in failure, or to reduce materially the usabilityof the unit of produc
17、t for its intended purpose. E22343.1.11 major defective, na unit of product which containsone or more major defects, and may also contain minor defectsbut contains no critical defect. E22343.1.12 minor defect, na defect that is not likely to reducematerially the usability of the unit of product for
18、its intendedpurpose, or is a departure from established standards havinglittle bearing on the effective use or operation of the unit.E22343.1.13 minor defective, na unit of product which containsone or more minor defects but contains no critical or majordefect. E22343.1.14 process average (in inspec
19、tion), nthe average per-cent defective or average number of defects per hundred units(whichever is applicable) of product submitted by the supplierfor original inspection. E22343.1.15 unit of product, nthat which is inspected in order todetermine its classification as defective or non-defective or t
20、ocount the number of defects. It may be a single article, a pair,a set, a length, an area, an operation, a volume, a component ofan end product, or the end product itself. E22343.1.15.1 DiscussionThe unit of product may or may notbe the same as the unit of purchase, supply, production, orshipment.3.
21、2 Definitions of Terms Specific to This Standard:3.2.1 checking inspection, nsampling inspection per-formed by the supplier on units of product which have alreadybeen 100 % inspected in order to determine the effectiveness ofthe screening crew.3.2.1.1 DiscussionThis inspection is performed at thesam
22、pling rate f or more often.3.2.2 clearance number, ni, the number of consecutiveconforming, that is, defect-free, units in 100 % inspectionrequired prior to qualifying for inspection on a sampling basis.3.2.3 conforming unit, na unit that meets the acceptancecriteria established for the characterist
23、ic being considered.3.2.4 defects concerned, ndefects being inspected forwhile using the sampling plan.3.2.5 inspection by defect class, nwhen one sampling planis associated with inspection for several kinds of defectscollectively and each unit of product inspected is inspected foreach of the defect
24、s in the class.3.2.6 inspection by individual defect, ninspection whereone sampling plan is associated with inspection for a singledefect, or where a sampling plan is applied to each of severaldefects independently.3.2.7 moving product, ninspection where product is flow-ing past the inspection stati
25、on.3.2.7.1 DiscussionIn the typical case the product moveson a conveyor belt or line; however, it may be moved in toteboxes, buggies or other conveyances which are operatedmanually or by mobile materials-handling equipment.3.2.8 multi-level, nplan consisting of periods of 100 %inspection and of samp
26、ling inspection at various rates whichreflect past inspection results.3.2.9 one hundred percent (100 %) inspection, nthe in-spection of every unit of product for the defects concernedlisted for an inspection station.3.2.9.1 DiscussionThe two terms, screening and 100 %inspection, are used interchange
27、ably in this practice.3.2.10 production interval, na finite period of production,N items in length.3.2.10.1 DiscussionThe production interval is normally ashift; it can be a day if it is reasonably certain that shift changesdo not affect quality of product, but shall not be longer than aday.3.2.11 p
28、roduction interval length, nN, specified numberof units to which CSP-F is to be applied.3.2.12 sampling frequency, nf, desired ratio between thenumber of units of product randomly selected and inspected atan inspection station and the number of unit passing theinspection station during periods of sa
29、mpling inspection.3.2.12.1 DiscussionIn this practice, each f is expressed asa fraction of the form, 1/7, 1/25, 1/50, etc. The procedure usedin selecting the sample units should give each unit of productpresented during periods of sampling inspection an equalchance of being selected and inspected. A
30、lso referred to as“frequency of sampling”.3.2.13 sampling inspection, ninspection for the defectsconcerned where the units selected for inspection are selectedby sampling.3.2.14 screening, n100 % inspection where all defectiveunits are removed from the production flow.3.2.14.1 DiscussionThe two term
31、s, screening and 100 %inspection, are used interchangeably in this practice.3.2.15 single-level, nplan consisting of alternating peri-ods of 100 % inspection and sampling inspection wherein thesampling rate is constant.4. Significance and Use4.1 The reason for preserving military sampling standards
32、isthat many organizations throughout the world still use thesestandards in their current form. MIL-STD-1235B is no longersupported by the U.S. Department of Defense as of themid-1990s and is out of print, but does exist in the publicdomain. This practice represents a conversion of MIL-STD-1235B to a
33、n ASTM-supported standard.4.2 This practice provides the tables and procedures forapplying five different types of continuous sampling plans forinspection by attributes. These continuous sampling plans arediscussed in Sections 6-10 of this practice and each sectionincludes information on:(a) Initiat
34、ion of 100 % inspection in use.(b) Requirements on when to switch to sampling inspec-tion.(c) Conditions warranting a return to 100 % inspection.(d) When a change in Code Letter, if desired, can be made.E2819 112(e) What to do when the checking inspector finds a defectthat was originally found confo
35、rming by the screening inspec-tor(s), that is, ineffective screening.(f) Situations where a defect is found before the switch to100 % inspection causing excessive periods of 100 % inspec-tion so action must be taken, that is, long periods of screening.4.2.1 Section 6 (Section 2 in MIL-STD-1235B) des
36、cribesspecific procedures and applications of the CSP-1 samplingplansa single-level continuous sampling procedure whichprovides for alternating between sequences of 100 % inspec-tion and sampling inspection.4.2.2 Section 7 (Section 3 in MIL-STD-1235B) describesspecific procedures and applications of
37、 the CSP-F samplingplansa variation of the CSP-1 plans in that CSP-F plans areapplied to a relatively short run of product, thereby permittingsmaller clearance numbers to be used.4.2.3 Section 8 (Section 4 in MIL-STD-1235B) describesspecific procedures and applications of the CSP-2 samplingplansa mo
38、dification of CSP-1 in that 100 % inspectionresumes only after a prescribed number of defect-free unitsseparate any two defective sample units.4.2.4 Section 9 (Section 5 in MIL-STD-1235B) describesspecific procedures and applications of the CSP-T samplingplansa multi-level continuous sampling proced
39、ure whichprovides for reducing the sampling frequency upon demonstra-tion of superior product quality.4.2.5 Section 10 (Section 6 in MIL-STD-1235B) describesspecific procedures and applications of the CSP-V samplingplansa single-level continuous sampling procedure which isan alternative to CSP-T in
40、that these plans provide for reducingthe clearance number in good quality situations where reduc-tion of sampling frequency has no economic merit.5. General Description of Sampling Plans5.1 This practice establishes continuous sampling plans andprocedures for inspection by attributes. When this prac
41、tice isreferenced in a contract, specification, inspection standard orsimilar document, the provisions of this practice shall governthe application of all attributes type continuous sampling plansand procedures. Unless otherwise noted herein, the provisionsof this practice shall be carried out by th
42、e supplier.5.2 ApplicationThe conditions that must exist beforethese sampling plans may be used are: (a) moving product, (b)ample space, equipment and manpower at or near the site ofinspection to permit rapid 100 % inspection when required, (c)relatively easy and quick inspection, (d) a process whic
43、h isproducing, or is capable of producing, material whose qualityis stable, and (e) the inspection is non-destructive. The sam-pling plans designated herein are applicable, but not limited, toinspection of various entities, viz., end items, components, rawmaterials, data or records, and any other en
44、tities, provided thatthe foregoing conditions are satisfied.5.3 Classification of Defects:5.3.1 Method of Classifying DefectsA classification ofdefects is the enumeration of possible defects of the unit ofproduct classified according to their seriousness. Defects willnormally be grouped into one or
45、more of the following classes;however, defects may be grouped into other classes, or intosubclasses within these classes.5.3.1.1 Critical DefectA critical defect is a defect thatjudgment and experience indicate is likely to result in hazard-ous or unsafe conditions for individuals using, maintaining
46、, ordepending upon the product; or a defect that judgment andexperience indicate is likely to prevent performance of thetactical function of a major end item such as a ship, aircraft,tank, missile, or space vehicle. Note that for a special provisionrelating to critical defects, see 5.8.2.5.3.1.2 Maj
47、or DefectA major defect is a defect other thancritical that is likely to result in failure or materially reduce theusability of the unit of product for its intended purpose.5.3.1.3 Minor DefectA minor defect is a defect that is notlikely to reduce materially the usability of the unit of productfor i
48、ts intended purpose, or is a departure from establishedstandards having little bearing on the effective use or operationof the unit.5.3.2 Method of Classifying DefectivesA defective is aunit of product which contains one or more defects. Defectiveswill usually be classified as follows:5.3.2.1 Critic
49、al DefectiveAcritical defective contains oneor more critical defects and may also contain major and minor,or both, defects. Note that for a special provision relating tocritical defectives, see 5.7.2.5.3.2.2 Major DefectiveAmajor defective contains one ormore major defects, and may also contain minor defects, butcontains no critical defects.5.3.2.3 Minor DefectiveAminor defective contains one ofmore minor defects but contains no critical or major defects.5.4 Acceptable Quality Level (AQL):5.4.1 DefinitionFor continuous sampling pl
