ASTM D2258-1999(2012) Standard Practice for Sampling Yarn for Testing 《试验用纱线抽样的标准操作规程》.pdf

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1、Designation: D2258 99 (Reapproved 2012)Standard Practice forSampling Yarn for Testing1This standard is issued under the fixed designation D2258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in

2、 parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice describes a procedure for the division ofshipment

3、s of yarn into test lots and the sampling of such lotsfor testing.1.2 This practice is applicable to single, plied, or cabledyarns, and cords, made of any fiber or mixture of fibers, andsupported on any form of package, including beams.1.3 This practice also describes procedures for the samplingof y

4、arn(s) removed from woven or knitted fabrics, however,when thus sampled, the yarns are usually not representative ofentire shipments, as referred to in 1.1. Consequently, theresultant sampling can only be used to determine the charac-teristics of the yarn and is usually not used for acceptancetestin

5、g. Moreover, it should be recognized that the character-istics of yarns from fabrics may be different than the charac-teristics of the same yarn(s), prior to being entered into thefabric manufacturing process.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately a

6、s the standard. Within the text,the inch-pound units are shown in parentheses. The valuesstated in each system are not exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith this practice.1.5 This stand

7、ard 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AS

8、TM Standards:2D123 Terminology Relating to TextilesD1578 Test Method for Breaking Strength of Yarn in SkeinFormD1907 Test Method for Linear Density of Yarn (YarnNumber) by the Skein MethodD4271 Practice for Writing Statements on Sampling in TestMethods for Textiles3D4849 Terminology Related to Yarns

9、 and Fibers3. Terminology3.1 For terminology related to Yarns and Fibers, see Termi-nology D4849.3.2 The following terms are relevant to this standard: beam,beam set, bulk sample, case, cone, end, fabric package,laboratory sample, lot, lot sample, primary sampling unit,production lot, sample, sampli

10、ng unit, sample skein, specimen,and yarn package.3.3 For definitions of all other textile terms see TerminologyD123.4. Summary of Practice4.1 Instructions are given for dividing the yarn into lots, fordetermining the number of cases, beams, or fabric packages tobe selected from each lot as a lot sam

11、ple, and for determiningthe number of packages, including the number of ends,representing those packages taken from the lot sample as alaboratory sample. See Practice D4271.5. Significance and Use5.1 Assigning a value to any property of the material in acontainer or in a lot, consignment, or deliver

12、y involves ameasurement process that includes both sampling and testingprocedures. The correctness of the value assigned dependsupon the variability due to testing. Even when the variabilitydue to testing is minimized by carefully developed procedures,correct and consistent estimates of the true val

13、ue of theproperty are possible only when the sampling procedure avoidssystematic bias, minimizes variations due to sampling, andprovides a laboratory sample of adequate size.1This practice is under the jurisdiction ofASTM Committee D13 on Textiles andis the direct responsibility of Subcommittee D13.

14、58 on Yarns and Fibers.Current edition approved March 1, 2012. Published April 2012. Originallyapproved in 1964. Last previous edition approved in 2005 as D2258 99(2005).DOI: 10.1520/D2258-99R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at

15、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West

16、 Conshohocken, PA 19428-2959, United States.5.2 Practice D2258 may not give the most efficient samplingplan that might be devised in special situations but does presenta general procedure that gives satisfactory precision with aneconomical amount of sampling and one which does notrequire elaborate s

17、tatistical computation based on previousknowledge of the amount of variation between primary sam-pling units (such as cases, beams or fabric packages), betweenunits of the laboratory sample taken from the primary samplingunits of the lot sample (such as yarn packages taken from acase) and between sp

18、ecimens taken from units of the laboratorysample (such as lengths of yarn taken from a yarn package ora fabric swatch taken from a roll or piece). Many plans thatinclude stratified sampling can be found in textbooks.5.3 The smallest number of specimens required for a givenvariability in the average

19、result will usually be obtained by (1)maximizing the number of shipping containers in the lotsample, (2) taking a single package end per shipping containerin the laboratory sample, and (3) taking only one specimen perpackage. Unfortunately, this is rarely the most economical wayto test a product bec

20、ause it normally costs most to take ashipping container as part of the lot sample, costs an interme-diate amount to take a package from a shipping container aspart of a laboratory sample, and costs least to take and test aspecimen from a package or yarn.5.4 To minimize the cost of sampling a lot of

21、material, it isnecessary to agree on the required variance for the reportedaverage for a lot of material:5.4.1 Estimate the variance due to lot samples, the variancedue to laboratory samples, and the variance due to testingspecimens.5.4.2 Calculate the total variance for average test results forseve

22、ral combinations of the number of lot samples, the numberof laboratory samples per lot sample, and the number ofspecimens per laboratory sample.5.4.3 Calculate the cost of performing each of the samplingschemes considered in 5.4.2.5.4.4 Select the sampling scheme that ( 1) has the requiredprecision

23、and (2) is most economical to perform.6. Procedure6.1 Division into LotsInstructions on the division ofproduct into lots is best given in the appropriate specification.In the absence of such instructions, sample and test as aseparate lot any portion of a shipment or order that differs fromother port

24、ions in specifications, put-up, or physical character-istics, or that is billed or designated by the supplier as aseparate lot. If portions of a larger order are shipped ondifferent dates, from plants or warehouses, or in more than onecarload or truckload, treat each such separately shipped portiona

25、s a separate lot. If the cases in a shipment do not haveconsecutive numbers, divide the shipment into groups of caseshaving consecutive numbers and treat each group as a separatelot if it is separated from an adjacent group by as many as tencase numbers. Treat each beam set as a separate lot.6.2 Lot

26、 SampleAs a lot sample for acceptance testing,unless otherwise agreed upon, as when specified in an appli-cable material specification, proceed as follows:NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween ship

27、ping units, between packages or ends within a shipping unit,and between specimens from a single package so as to provide a samplingplan with a meaningful producers risk, consumers risk, acceptablequality level, and limiting quality level.6.2.1 Cases or Fabric PackagesFor the lot sample, assigneach c

28、ase or fabric package with consecutive numbers and takefor acceptance testing, the number of cases or fabric packagesspecified in Table 1. Select the cases or fabric packages by arandom process using the assigned numbers by either placingthese numbers on small slips or chips, placing them in acontai

29、ner, mixing thoroughly and drawing out the number ornumbers by selection, or by using a random number table or itscomputer equivalent.6.2.1.1 When fabric packages, such as bolts or pieces, arecontained in cases, consider the case as the sampling unit.When fabric packages, such as rolls are self-cont

30、ained, con-sider the individual fabric package as the sampling unit.6.2.1.2 When known, fabric packages, such as rolls, pieces,or bolts produced from one beam set may be treated in thesame manner as beams.6.2.2 BeamsFor the lot sample, assign each beam withconsecutive numbers and take for acceptance

31、 testing, one beamfrom the beam set. Select the beam by a random process usingthe assigned numbers by either placing these numbers on smallslips or chips, placing them in a container, mixing thoroughlyand drawing out the number by selection, or by using a randomnumber table or its computer equivalen

32、t.6.3 Laboratory SampleFor a laboratory sample for accep-tance testing, unless otherwise agreed upon, as when specifiedin an applicable material specification, proceed as follows:6.3.1 CasesWhen sampling cases, take a total of tenpackages from the lot sample. When there are five cases in thelot samp

33、le, select randomly two packages from each case.When there are four cases in the lot sample, select randomlytwo packages from each case then randomly select two of thefour cases and select randomly a third package from each of theselected cases. When there are three cases in the lot sample,select ra

34、ndomly three packages from each case then randomlyselect one of the three cases and select randomly a fourthpackage from the selected case. When there are two cases inthe lot sample, select randomly five packages from each case.When there is one case in the lot sample, select randomly tenpackages fr

35、om the case.6.3.2 Fabric PackagesWhen sampling fabric packages,discard the outside layer of the fabric package, and then take afull width swatch,2m(2yd.) from each selected lot samplingTABLE 1 Number of Cases, Beams, or Fabric PackagesA ,BIn Lot In Lot Sample112to4 25to9 310 to 19 420 or more 5AFor

36、cases containing only a few packages per case, enough cases must betaken in the lot sample so there will be at least ten packages in the lot sample. (See6.2.2.1 and 6.2.2.2.)BTable 1 is an empirical practice schedule found by experience to besatisfactory for the lot sample from homogeneous lots of y

37、arn or fabric supportpackages, such as rolls or boards.D2258 99 (2012)2unit. Treat each type of yarn in the fabric, the warp and fillingyarns in woven fabrics, and the machine direction of knittedfabrics as separate sampling units. Take a total of ten endsfrom the fabric swatches. When there are fiv

38、e swatches in thelot sample, select randomly two ends from each swatch. Whenthere are four swatches in the lot sample, select randomly twoends from each swatch then randomly select two of the fourswatches and select randomly a third end from each of theselected swatches. When there are three swatche

39、s in the lotsample, select randomly three ends from each swatch thenrandomly select one of the three swatches and select randomlya fourth end from the selected swatch. When there are twoswatches in the lot sample, select randomly five ends from eachswatch. When there is one swatch in the lot sample,

40、 selectrandomly ten ends from the swatch. Remove ends from thefabric swatches as directed in 6.3.4, 6.3.5, and 6.3.6,asrequired.NOTE 2Individual yarns removed from fabric may come from severalyarn shipments and may not be representative of a given yarn lot. Yarnsremoved from fabric are generally use

41、d for identification purposes.6.3.3 BeamsWhen sampling beams of yarn, take ten endsfrom the first beam in the lot sample. Randomly take the firstend from among those included between 2.5 and 7.5 % of thebeam end count from one beam flange. Take the other nineends from positions each 10 % of the beam

42、 end count from thefirst end toward the other beam flange. When sampling yarn onbeams, reel sample skeins, or reel test skeins directly from thebeams using minimal tension to prevent stretching of yarns.Place the beam containing the yarn to be tested on two bearingshigh enough for the beam flanges t

43、o clear the floor. Attach acrank arm to one end of the beam shaft. Place the reel aconvenient distance from the beam to draw the yarn from thebeam at less than a 20 angle. Fasten the required number ofends from the beams to the reel. Let one operator turn the beamslowly to unwind the yarn while a se

44、cond operator turns thereel fast enough to take up the yarn as it comes from the beam.NOTE 3In using beams after the test ends have been removed, a set ofspools containing the same kind of yarn or thread as that on the beam maybe placed behind the beam on a small creel to replace the ends that haveb

45、een used for testing. When the ends which supply the test skeins come upon the beam, the auxiliary spools may be broken out.6.3.4 Sample SkeinsIt is often preferable, but is notmandatory except when sampling yarn on beams, to reelsample skeins. Skeins condition more rapidly than tightlywound package

46、s, and it is sometimes more convenient tohandle the laboratory sample in skein form. From each of theyarn packages or ends selected for the laboratory sample, reela skein containing sufficient length to provide all the specimensrequired. If yarn strength or yarn number is to be determinedby skein me

47、thods, the test skeins specified in Test MethodD1578 and Test Method D1907 may be reeled directly from theyarn packages or beams, and additional sample skeins may bereeled as a source of specimens for other tests. Remove theyarn from packages either by drawing over the end of bobbins,cops, cones, et

48、c., or from the side of flanged spools or beams,whichever is done in normal use. When the normal means ofyarn removal is not known, draw the yarn from the side of thepackage. Removal of yarn over-end drawing from the sideresults in a difference of twist of 1/p d, where d is the packagediameter. When

49、 several ends are wound parallel on a singlepackage or beam, draw each end through a separate guide andreel a skein from each selected end in the laboratory sample,drawing from the side of the package form or beam.6.3.5 Removing Yarn from Woven Fabrics Cut the fabricparallel to the direction (warp or filling yarns) to be tested.Ravel and discard the warp (or filling) yarns until full lengthyarns can be removed from the fabric swatch.NOTE 4If the fabric is tightly woven, it may be necessary to cut thefringe frequently to allow the yarns to be raveled from the fabric