1、Designation: D 6612 00 (Reapproved 2006)e1Standard Test Method forYarn Number and Yarn Number Variability Using AutomatedTester1This standard is issued under the fixed designation D 6612; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESection 3 was updated editorially in August 2006.1. Scope1.1 This test method covers the measurement of ya
3、rnnumber up to 4000 dtex (3600 denier) and related variabilityproperties 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), de
4、nsityfrequency variation.NOTE 1For determination of yarn number by use of reel and balance,refer to Test Method D 1907. For another method of measuring variability(unevenness) in yarn, refer to Test Method D 1425.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separate
5、ly as standard. Within the text, theinch-pound units are in parentheses. 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 pu
6、rport 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 ASTM Standards:D
7、123 Terminology Relating to TextilesD 1425 Test Method for Unevenness of Textile StrandsUsing Capacitance Testing EquipmentD 1776 Practice for Conditioning and Testing TextilesD 1907 Test Method for Linear Density of Yarn (YarnNumber) by the Skein MethodD 2258 Practice for Sampling Yarn for TestingD
8、 4849 Terminology Relating to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns andFibers, refer to Terminology D 4849.3.1.1 The following terms are relevant to this standard:cotton count, coefficient of variation, denier, linear density, tex,yarn number, yarn numbering
9、 system, bad/good test, densityfrequency variability, density spread.3.2 For all other textile terms used in this test method, seeTerminology D 123.4. Summary of Test Method4.1 A specified length of yarn (specimen) is stripped auto-matically directly from the package, cut, and weighed. Theyarn numbe
10、r is calculated by interfaced computer, displayed ona monitor, and may 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 cou
11、nted for calculation ofvariability properties: %DS, %CV, %BGT and %DFV.5. Significance and Use5.1 Test Method D 6612 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
12、-tween the reported test results for two or more laboratories,comparative 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 aspo
13、ssible, drawn from the same lot of material as the samplesthat results in disparate results during initial testing, andrandomly assigned in equal numbers to each laboratory. Otherfabrics with established tests values are used for this purpose.The test results from the laboratories involved should be
14、compared 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 is1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Sub
15、committee D13.58 on Yarns and Fibers.Current edition approved June 1, 2006. Published August 2006. Originallyapproved in 2000. Last previous edition approved in 2000 as D 661200.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.found,
16、either its cause must be found and corrected, or futuretest results adjusted in consideration of the known 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.
17、If a bias is found, either its cause must be found andcorrected or the purchaser and the supplier must agree tointerpret future test results with consideration to the knownbias.5.2 Test Method D 6612 also is used for the quality controlof filament yarns.5.3 Indices of Variability:5.3.1 Coeffcient of
18、 Variation%CV is a standard statisticalcalculation and is the most common index of yarn unevenness.For most 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 discr
19、iminating that %DS.5.3.2 Bad/Good Test%BGT, which will normally be up to20 % greater than %DS value, emphasizes 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 Den
20、sity Spread%DS is equivalent to the Uster %unevenness (Test Method D 1425) and is an indication ofshort-term 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
21、 spread for a yarn productwill depend on the yarn manufacturing process and end use. Aspread of 34 % generally 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 Frequen
22、cy VariabilityDFV is an index ofspacing variability, whereas the others are indices of magnitudeor unevenness. 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 I
23、nstrument(ACW), (automatic-cut-and-weigh) ACW with interfacedcomputer (see Fig. 1)6.2 Density Variability 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 (2
24、161200 denier).6.2.4 Ultra-High (3.2-mm slit), 13344000 dtex(12013600 denier).6.3 Calibration Weights, 2-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 anapplic
25、able material specification or other agreement betweenthe purchaser and the supplier, such as an agreement to usePractice D 2258. Consider shipping cases or other shippingunits to be the primary sampling units.NOTE 2An adequate specification or other agreement between thepurchaser and the supplier r
26、equires taking into account the variabilitybetween shipping units, between packages or ends within a shipping 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 Laborator
27、y SampleAs a laboratory sample for accep-tance testing, take at random from each shipping unit in the lotsample 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 PracticeD 2258. Preferably, t
28、he same number of packages should betaken from each shipping unit in the lot sample. If differingnumbers of 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 p
29、ackageof filament yarn and five specimens from each package of spunyarns. A 240-m specimen is needed for variability 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
30、 6 1 (70 6 2F) and 65 6 2%relative humidity, for not less than 4 h, see Practice D 1776.9. Preparation and 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
31、with the freerunning of the yarn from the package.10.2 String up the yarn, input sample and specimen infor-mation, and test the specimen as directed in the manufacturersmanual. The tester is automatically controlled. See the appen-dix for default operation condition values.10.3 The computer software
32、 calculates 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.FIG. 1 ACW/DVA (Automatic-Cut-and Weigh with DensityVariability Accessory) TesterD 6612 00 (2006)e1211. C
33、alculation11.1 Yarn Number:11.1.1 The calculation for the yarn number as dtex or denieris based on Eq 1.N 5 K 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 calcu
34、lation 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)where: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 automa
35、tically averages the five tests froma package of spun yarn and only reports this average for the package.11.1.3 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
36、)where:DS = Density spread, %DS,H = Highest value for yarn number for the 30-m segment,L = Lowest value for yarn 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
37、 is calculated by thecomputer for all the variability observations taken.11.3.2 Calculate the %CV for the lot.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
38、thespecimen and expressed as a percent.11.4.2 Calculate the %BGT for the lot.11.5 Density Frequency Variation: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 yar
39、n was tested as directed in Test MethodD 6612. Describe the material or product sampled and themethod of sampling.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 te
40、st method.13. Precision and Bias13.1 PrecisionAn interlaboratory test is in process; analy-sis for a precision 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 li
41、mitation, Test Method D 6612 has noknown bias.14. Keywords14.1 linear density; variability, yarn; yarn; yarn numberAPPENDIX(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 lea
42、st 30 min before calibrating the scale.X1.1.2 Enter the computer command to automaticallycalibrate both the DVA 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 period
43、ic checks and inspections of thetester as noted in the manufacturers manual.X1.1.5 Set the tester 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
44、.D 6612 00 (2006)e13X1.2 Default specimen lengths for the different yarnnumber ranges are shown in Table X1.1.X1.3 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 hi
45、ghest andlowest mass among the 480 measurements made.X1.4.2 For %CV, the tester makes 480 measurements ofmass, one 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 from
46、higher-to-lower and lower-to-higher in the next 190 m.X1.4.4 For %DS, the specimen is mathematically dividedinto eight 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 a
47、sserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination 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
48、 by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved 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 re
49、ceive 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, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-955
