1、Designation: D6612 00 (Reapproved 2011)Standard Test Method forYarn Number and Yarn Number Variability Using AutomatedTester1This standard is issued under the fixed designation D6612; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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 test method covers the measurement of yarnnumber up to 4000 dtex (3600 denier) and related variabili
3、typroperties of filament and spun yarns using an automated testerwith capability for measuring mass variability characteristics.1.2 Yarn number variability properties include percent den-sity spread (%DS), coefficient of variation (%CV), densityfrequency variation.NOTE 1For determination of yarn num
4、ber by use of reel and balance,refer to Test Method D1907. For another method of measuring variability(unevenness) in yarn, refer to Test Method D1425.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Within the text, theinch-pound units are in pa
5、rentheses. The values stated in eachsystem are not exact equivalents; therefore, each system shallbe used independently of the other. Combining values from thetwo systems may result in inaccuracies of results.1.4 This standard does not purport to address all of thesafety concerns, if any, associated
6、 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 ASTM Standards:2D123 Terminology Relating to TextilesD1425 Test Method for Unev
7、enness of Textile StrandsUsing Capacitance Testing EquipmentD1776 Practice for Conditioning and Testing TextilesD1907 Test Method for Linear Density of Yarn (YarnNumber) by the Skein MethodD2258 Practice for Sampling Yarn for TestingD4849 Terminology Related to Yarns and Fibers3. Terminology3.1 For
8、all terminology relating to D13.58, Yarns andFibers, refer to Terminology D4849.3.1.1 The following terms are relevant to this standard:cotton count, coefficient of variation, denier, linear density, tex,yarn number, yarn numbering system, bad/good test, densityfrequency variability, density spread.
9、3.2 For all other textile terms used in this test method, seeTerminology D123.4. Summary of Test Method4.1 A specified length of yarn (specimen) is stripped auto-matically directly from the package, cut, and weighed. Theyarn number is calculated by interfaced computer, displayed ona monitor, and may
10、 be printed. The yarn number can bereported in tex, denier, or cotton count units.4.2 Simultaneously, by means of a capacitance cell, themass of the specimen is measured in subsections and frequencyof mass value crossovers are counted for calculation ofvariability properties: %DS, %CV, %BGT and %DFV
11、.5. Significance and Use5.1 Test Method D6612 for yarn number and yarn numbervariability is satisfactory for acceptance of commercial ship-ments and is used in the trade.5.1.1 If there are differences of practical significance be-tween the reported test results for two or more laboratories,comparati
12、ve tests should be performed by those laboratories todetermine if there is a statistical bias between them, usingcompetent statistical assistance. As a minimum, samples usedfor each comparative tests should be as homogeneous aspossible, drawn from the same lot of material as the samplesthat results
13、in disparate results during initial testing, andrandomly assigned in equal numbers to each laboratory. Other1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved May 1, 2011. P
14、ublished July 2011. Originally approvedin 2000. Last previous edition approved in 2006 as D661200(2006)1. DOI:10.1520/D6612-00R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
15、ion, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.fabrics with established tests values are used for this purpose.The test results from the laboratories involved shou
16、ld becompared appropriate statistical analysis and a probabilitylevel chosen by the two parties before testing begins, at aprobability level chosen prior to the testing series. If a bias isfound, either its cause must be found and corrected, or futuretest results adjusted in consideration of the kno
17、wn bias.5.1.2 The average results from the two laboratories shouldbe compared using appropriate statistical analysis and a prob-ability level chosen by the two parties before the testing isbegun. If a bias is found, either its cause must be found andcorrected or the purchaser and the supplier must a
18、gree tointerpret future test results with consideration to the knownbias.5.2 Test Method D6612 also is used for the quality controlof filament yarns.5.3 Indices of Variability:5.3.1 Coeffcient of Variation%CV is a standard statisticalcalculation and is the most common index of yarn unevenness.For mo
19、st textile applications in the 80330 dtex (70300denier) range, a 1.01.3 %CV is adequate. %CV of yarnscoarser than 666 dtex (600 denier) is not routine and usuallynot meaningful. %CV is less discriminating that %DS.5.3.2 Bad/Good Test%BGT, which will normally be up to20 % greater than %DS value, emph
20、asizes the greatest spreadin the entire length tested, (%DS is an average). If the value isgreater than 50 % of the %DS, it suggests that there is a processthat needs to be investigated.5.3.3 Density Spread%DS is equivalent to the Uster %unevenness (Test Method D1425) and is an indication ofshort-te
21、rm variability. Yarns with extreme values are morelikely to cause trouble in subsequent yarn processes, whichmakes this perhaps the most useful index. The minimumachievable and maximum tolerance spread for a yarn productwill depend on the yarn manufacturing process and end use. Aspread of 34 % gener
22、ally is, for most textile applications, inthe range of 160550 dtex (150 to 500 deniers). More criticalapplications, such as those using finer yarns, may require lowervalues.5.3.4 Density Frequency VariabilityDFV is an index ofspacing variability, whereas the others are indices of magnitudeor unevenn
23、ess. Frequency variability can induce resonance inhigh-speed processing and is a common source of barre, dyestreaks, or patterned unevenness in fabrics.6. Apparatus6.1 Automatic Yarn Numbering Instrument (ACW), (auto-matic-cut-and-weigh) ACW with interfaced computer (see Fig.1)6.2 Density Variabilit
24、y Accessory (DVA),3with yarn num-ber ranges:6.2.1 Low (9.7-mm slit), up to 30 dtex (up to 27 denier).6.2.2 Medium (1.2-mm slit), 31239 dtex (25215 denier).6.2.3 High (2.2-mm slit), 2401333 dtex (2161200 denier).6.2.4 Ultra-High (3.2-mm slit), 13344000 dtex(12013600 denier).6.3 Calibration Weights, 2
25、-g and others as needed to coverthe tex (denier) ranges of interest.7. Sampling7.1 Lot SampleAs a lot sample for acceptance testing,take at random the number of shipping units directed in anapplicable material specification or other agreement betweenthe purchaser and the supplier, such as an agreeme
26、nt to usePractice D2258. Consider shipping cases or other shippingunits to be the primary sampling units.NOTE 2An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between packages or ends within a ship
27、ping unit,and between specimens from a single package to provide a sampling planwith a meaningful producers risk, consumers risk, acceptable qualitylevel, and limiting quality level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take at random from each shipping unit in the lot
28、sample the number of packages directed in an applicablematerial specification or other agreement between the pur-chaser and the supplier, such as an agreement to use PracticeD2258. Preferably, the same number of packages should betaken from each shipping unit in the lot sample. If differingnumbers o
29、f packages are to be taken from shipping units in thelot sample, determine at random, which shipping units are tohave each number of packages drawn.7.3 Test SpecimenTest one specimen from each packageof filament yarn and five specimens from each package of spunyarns. A 240-m specimen is needed for v
30、ariability parameters.see Table X1.1 for the lengths of yarn for yarn numberspecimen lengths.8. Conditioning8.1 Condition the packages in the standard atmosphere fortesting textiles, which is 21 6 1 (70 6 2F) and 65 6 2%relative humidity, for not less than 4 h, see Practice D1776.9. Preparation and
31、Calibration of Apparatus9.1 Set up the tester as prescribed in Appendix X1.10. Procedure10.1 Check each package for cleanliness, overthrown endsand any package formation, which might interfere with the freerunning of the yarn from the package.10.2 String up the yarn, input sample and specimen infor-
32、mation, and test the specimen as directed in the manufacturersmanual. The tester is automatically controlled. See the appen-dix for default operation condition values.FIG. 1 ACW/DVA (Automatic-Cut-and Weigh with DensityVariability Accessory) TesterD6612 00 (2011)210.3 The computer software calculate
33、s the yarn number andcompares this value to the capacitance head estimate of theyarn number. If the two agree within specified limits, thesystem proceeds, otherwise the test is aborted.11. Calculation11.1 Yarn Number:11.1.1 The calculation for the yarn number as dtex or denieris based on Eq 1.N 5 K
34、3 M/L (1)where:N = yarn number in direct system, dtex (denier),K = constant depending on numbering system, 10 000(9000),M = mass of specimen, g, andL = length of specimen, m.11.1.2 The calculation for cotton count N is based on Eq 2,Eq 3, or Eq 4:N 5 K 3 L/M (2)N 5 5905.41/T (3)N 5 5314.87/D (4)wher
35、e:N = cotton count,K = constant for cotton 0.590541,L = length of specimen, m,M = mass of specimen, g,T = linear density, dtex, andD = linear density, denier.NOTE 3The tester computer automatically averages the five tests froma package of spun yarn and only reports this average for the package.11.1.
36、3 Calculate the average yarn number for eachlaboratory-sampling. unit and for the lot.11.2 Density Spread (%DS):11.2.1 The calculation for %DS for each specimen is basedon Eq 5.DS 5HL!/8A (5)where:DS = Density spread, %DS,H = Highest value for yarn number for the 30-m segment,L = Lowest value for ya
37、rn number for the 30-m segment,andA = reference yarn number obtained by the DVA.11.2.2 Calculate the %DS value for the lot.11.3 Coeffcient of Variation (TCV):11.3.1 The %CV for each specimen is calculated by thecomputer for all the variability observations taken.11.3.2 Calculate the %CV for the lot.
38、11.4 Bad/Good Test (%BGT):11.4.1 The BGT is calculated by the computer as thedifference between the maximum and minimum readings forthe total specimen divided by the average yarn number for thespecimen and expressed as a percent.11.4.2 Calculate the %BGT for the lot.11.5 Density Frequency Variation:
39、11.5.1 The DFV is determined by the computer as theaverage number of crossovers of the analog signal not using thefirst 50 m.11.5.2 Calculate the DFV for the lot.12. Report12.1 State the yarn was tested as directed in Test MethodD6612. Describe the material or product sampled and themethod of sampli
40、ng.12.2 Report the following information:12.2.1 The yarn number for each specimen and for the lot,12.2.2 The %BGT, %CV, %DS, and DFV for each speci-men, and12.2.3 Any modification in the test method.13. Precision and Bias13.1 PrecisionAn interlaboratory test is in process; analy-sis for a precision
41、and bias statement will be provided as soonas possible.13.2 BiasThe values for yarn number and yarn numbervariability properties can be defined only in terms of a testmethod. Within this limitation, Test Method D6612 has noknown bias.14. Keywords14.1 linear density; variability, yarn; yarn; yarn num
42、berAPPENDIX(Nonmandatory Information)X1. ACW AUTOMATED TESTER WITH DVAX1.1 Preparation and Calibration of Apparatus:X1.1.1 Turn on the motor and allow theACW/DVAtester towarm up for at least 30 min before calibrating the scale.X1.1.2 Enter the computer command to automaticallycalibrate both the DVA
43、unit and the scale, and zero the scale.X1.1.3 To eliminate errors due to long-term drift, set thetester to automatically tare the balance after each set of 20tests.X1.1.4 Make other periodic checks and inspections of thetester as noted in the manufacturers manual.D6612 00 (2011)3X1.1.5 Set the teste
44、r for operation in Mode 2 with the ModelACW, T, and DVA.X1.1.6 Computer commands and prompts, error messages,diagnostic test commands, and trouble shooting informationare given in the manufacturers manual.X1.2 Default specimen lengths for the different yarnnumber ranges are shown in Table X1.1.X1.3
45、Default operation parameters for the DVA are shownin Table X1.2.X1.4 Values Obtained by the Computer During the Test forUse in Calculations:X1.4.1 For %BGT, the tester determines the highest andlowest mass among the 480 measurements made.X1.4.2 For %CV, the tester makes 480 measurements ofmass, one
46、every 0.5 m.X1.4.3 For DFV, after measuring the mean mass of the first50 m as a reference, the tester counts the number of times themeasured mass crosses over the average mass line fromhigher-to-lower and lower-to-higher in the next 190 m.X1.4.4 For %DS, the specimen is mathematically dividedinto ei
47、ght subsections of 30 m each and the maximum andminimum mass values within each subsection determined.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that de
48、termination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved
49、or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
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