ASTM D3412-2007 Standard Test Method for Coefficient of Friction Yarn to Yarn《纱与纱之间摩擦系数的标准试验方法》.pdf

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1、Designation: D 3412 07Standard Test Method forCoefficient of Friction, Yarn to Yarn1This standard is issued under the fixed designation D 3412; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of frictionalproperties for both continuous filament and spun-staple yarnsunder boundary friction condit

3、ions.1.2 This test method has been used with yarns having lineardensities ranging from 1.5 to 200 tex, but may be used withyarns outside these ranges (15 to 1800 denier).NOTE 1For coefficient of friction, yarn to metal, see Test MethodD 3108.1.3 The values stated in SI units are to be regarded as th

4、estandard. The inch-pound units given in parentheses are forinformation only.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 safety and health practices and determ

5、ine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 1907 Test Method for Linear Density of Yarn (YarnNumber) by the Skein MethodD 2258 Practice for Sampli

6、ng Yarn for TestingD 3108 Test Method for Coefficient of Friction, Yarn toSolid MaterialD 4849 Terminology Relating to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns andFibers, refer to Terminology D 4849.3.2 For all other terminology related to textiles, refer toTer

7、minology D 123.4. Summary of Test Method4.1 A length of yarn is moved at a known speed in contactwith itself or similar yarn at a specified wrap angle. The inputand output tensions are measured and the coefficient of frictioncalculated. Alternatively, apparatus may be used in which theratio of input

8、 to output tension is measured allowing thecoefficient of friction to be indicated directly.4.2 Two optional procedures are included. Option 1 is basedon the Twisted Strand Method, using a wrap angle of 15.71 rad(900). Option 2 is based on the Capstan Method, using a wrapangle of 3.14 radians (180).

9、NOTE 2Editions of Test Method D 3412 prior to the 1986 revisionincorrectly stated the wrap angle for Option 1 to be 18.85 rad. This isincorrect, since 3 turns of the swivel pulley do not result in a wrap angleof 18.85 radians. This has now been corrected to 15.71 rad. This should betaken into accoun

10、t in comparing with earlier results.5. Significance and Use5.1 This test method for testing yarn-to-yarn friction isbeing used, but is not recommended, for acceptance testing ofcommercial shipments since between-laboratory precision isknown to be poor.5.1.1 In some cases, the purchaser and supplier

11、may have totest a commercial shipment of one or more specific materialsby the best available method even though the method has notbeen recommended for acceptance testing of commercialshipments. In case of a dispute arising from differences inreported test results when using Test Method D 3412 foracc

12、eptance testing of commercial shipments, the purchaser andthe supplier should conduct comparative tests to determine ifthere is a statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation ofbias. As a minimum, the two parties should take a grou

13、p of testspecimens that are as homogeneous as possible and that arefrom a lot of material of the type in question. The testspecimens should then be randomly assigned in equal numbersto each laboratory for testing. The average results from the twolaboratories should be compared using Students t-test

14、forunpaired data and an acceptable probability level chosen by the1This 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 Jan. 1, 2007. Published January 2007. Originallyapproved

15、 in 1975T. Last previous edition approved in 2001 as D 3412 01.2For referenced 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 websit

16、e.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.two parties before the testing is begun. If a bias is found, eitherits cause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results w

17、ith consid-eration to the known bias.5.2 This test method is intended for the determination ofyarn-to-yarn boundary friction coefficients measured over aspecified length of yarn.5.3 The test method is useful for quality control, research,and the characterization of yarn boundary lubricants.NOTE 3Bec

18、ause the geometry of the yarns is different, Options 1 and2 should not be expected to give the same numerical values on the sameyarns.6. Apparatus6.1 Option 1 (Twisted Strand Method)A schematic dia-gram of the elements required for twisted strand frictionmeasurement is shown in Fig. 1. The yarn is r

19、un over upperpulleys and under a lower pulley and is intertwisted betweenthese pulleys. One end of the yarn (output) is taken up at acontrolled rate. The other end of yarn (input) is maintained ata controlled tension. The number of intertwisting wraps, theapex angle between the input and output yarn

20、s, and the inputand output tensions are precisely known or recorded. Fromthese data the coefficient of yarn-on-yarn friction is calculated.The required elements are:6.1.1 Friction Testing Apparatus (Indirect)3Apparatus inwhich the input tension is measured, or controlled to a setvalue, the output te

21、nsion is measured, and the coefficient offriction is calculated within or outside the apparatus.6.1.1.1 Yarn Input Tension ControlAmeans of controllingthe yarn input tension to the nearest 5 % is required. Ademand-feed apparatus tensioned with a fixed weight is suit-able.6.1.1.2 Yarn Input Tension M

22、easurementThe yarn inputtension is measured to within 65.0 mN (60.5 gf), using asuitable tension gage producing an electrical signal. The signalis recorded as millinewtons (grams-force) or is used in com-bination with the yarn output tension measured to calculate thecoefficient of friction. If a dem

23、and-feed apparatus tensionedwith a precise, known fixed mass is used, the yarn input tensionneed not be constantly measured and recorded.6.1.1.3 Yarn Output Tension MeasurementYarn outputtension is measured to within 65.0 mN (60.5 gf), using asuitable tension gage producing an electrical signal. The

24、 signalis recorded as millinewtons, (grams-force), or is used incombination with the yarn input tension setting or measure-ment to calculate the coefficient of friction.6.1.2 Friction Testing Apparatus (Direct)4Apparatus inwhich the ratio of output to input tensions are compareddirectly and the coef

25、ficient of friction is indicated on a scale.6.1.3 Auxilliary Equipment (Indirect and Direct):6.1.3.1 Guide Pulley ArrangementThe upper and lowerpulleys shalls be of the same diameter. The recommendedpulley diameter is 38 mm (1.5 in.). The separation distancebetween the upper pulleys, 2 H, shall be 1

26、40 6 2 mm (5.5 60.1 in.). The separation distance between the axis of the lowerpulley and a line connecting the upper pulley axes, V, shall be280 6 2mm(116 0.1 in.). All pulleys shall be in the sameplane. The lower pulley may optionally be mounted so that itcan be swiveled around an axis at right an

27、gles to its axis ofrotation and then fixed in position in the same plane as theupper pulleys.6.1.3.2 Drive UnitThe yarn takeup shall run between 20and 100 mm/min (0.75 and 4.0 in./min).6.2 Option 2 (Capstan Method)A schematic diagram ofthe elements required for the Capstan Method is shown in Fig.2.

28、Suitable elements are:6.2.1 CylinderA rotating mandrel of 50 6 2 mm (2.0 60.1 in.) outside diameter.6.2.2 Drive UnitA mechanism designed to rotate thecylinder at a surface speed of 20 6 1 mm/min (0.75 6 0.04in./mm).3Equipment meeting these requirements may be obtained commercially from:Custom Scient

29、ific Instruments Inc, 13 Wing Drive, Cedar Knolls, NJ 07292, andRothschild-Messinstruments, Traubstr 3, 8002 Zurich, Switzerland, represented inthe U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388, Spartanburg, SC 29304.4Equipment meeting these requirements may be obtained commercially from:Rothsch

30、ild-Messinstruments, Traubstr 3, 8002 Zurich, Switzerland, represented inthe U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388, Spartanburg, SC 29304,and Shirley Developments Ltd, PO Box 6, Didsbury, Manchester M20 8SA,England, represented in the U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388,Spa

31、rtanburg, SC 29304.FIG. 1 Twisted Strand Yarn-to-Yarn Friction ApparatusTwisted-Yarn MethodD34120726.2.3 Winding UnitA device to wrap the yarn on thesurface of the cylinder. A helix angle of 0.2 to 0.3 rad (10 to15) is needed to prevent burrowing by the hanging strand ofyarn.6.2.4 Tension GageA suit

32、able tension gage, producing anelectrical signal, to measure the yarn output tension which isrecorded as millinewtons or after calculation as coefficient offriction.6.2.5 WeightsAset of weights or other device to preset theinput tension.NOTE 4Measured stick-slip differentials are greatly dependent o

33、ntension transducer spring constants, yarn modulus, and recorder frequencyresponses. If interlaboratory checks are required, the same type of tensiontransducer and recorder should be used and the distance between thetransducer and the hanging weight to center line of the mandrel must bespecified.7.

34、Sampling7.1 Lot SampleAs a lot sample for acceptance testing,take at random the number of shipping containers directed inan applicable material specification or other agreement be-tween the purchaser and the supplier, such as an agreement touse Practice D 2258. Consider shipping containers to be the

35、primary sampling units.NOTE 5An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between packages or ends within a shipping unit,and between specimens from a single package so as to provide a samplingp

36、lan with a meaningful producers risk, consumers risk, acceptablequality level, and limiting quality level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take at random from each shipping unit in the lotsample the number of packages or ends directed in anapplicable material spec

37、ification or other agreement betweenthe purchaser and the supplier such as an agreement to usePractice D 2258. Preferably, the same number of packagesshould be taken from each shipping unit in the lot sample. Ifdiffering numbers of packages are to be taken from shippingunits in the lot sample, deter

38、mine at random which shippingunits are to have each number of packages drawn.7.3 Test SpecimensTest one specimen from each packagein the laboratory sample.8. Conditioning8.1 Preparation of Test PackagesRemove sufficient yarnfrom the test packages to avoid testing non-representativelayers. If in doub

39、t, remove about 10 % of the length of yarn onthe package.8.2 The strand to be tested must have a uniform moisturecontent along its length. Atmospheric conditions must there-fore be stable and the strand must be in equilibrium with theprevailing atmosphere. To satisfy this condition, testing shouldbe

40、 carried out after thorough conditioning in the standardatmosphere for testing textiles.8.3 PreconditioningPrecondition packages of yarn for atleast3hinanatmosphere with a relative humidity between 5and 25 % and a temperature not exceeding 50C (121F).8.4 ConditioningCondition the preconditioned pack

41、agesof yarn in the standard atmosphere for testing textiles (relativehumidity 65 6 2 % and temperature 21 6 1C (70 6 2F) inmoving air until it has reached moisture equilibrium for testing,as directed in Practice D 1776.9. Procedure9.1 Test all specimens in the standard atmosphere for testingtextiles

42、, which is a relative humidity 65 6 2 % and temperature216 1C (70 6 2F).9.2 Option 1 (Twisted Strand Method):9.2.1 Calibrate the apparatus to the specified full scalereading. Check the freedom of the pulleys by running yarnthrough the apparatus to determine the difference betweeninput and output ten

43、sions with no yarn friction. Designate thisvalue as DT.9.2.2 Feed the yarn through the apparatus. If the testapparatus is equipped with a rotating lower pulley, rotate theswivel pulley clockwise through three complete revolutions.Otherwise, remove the yarn from the lower pulley by placingit around f

44、ingers, rotate the hand to twist the yarn loop threecomplete revolutions, and then replace the yarn under thelower pulley. The first half revolution brings the input andoutput sections of the yarn into contact and corresponds to awrap angle of zero. The additional two and one-half revolu-tions produ

45、ces a wrap angle of 15.7 rad (900).9.2.3 Measure the length W of the intertwisted portion ofyarn. Measure the distance between the upper pulley axes 2Hand the distance between the lower pulley axis and a lineconnecting the upper pulley axes V, or use the predeterminedvalues for these constants. Calc

46、ulate the apex angle a formedbetween the input and output yarns using Eq 1:a52 arctan 5SHV 2 WD(1)9.2.4 Place a mark on the input yarn immediately above itsentry into the intertwisted region.9.2.5 Adjust the input tension to 10.0 6 0.5 mN/tex (0.1gf/den). If the yarn linear density is not known, det

47、ermine asdirected in Test Method D 1907 (Option I). For heavy yarns(30 tex or greater), an input tension of less than 10.0 mN/tex(0.1 gf/den) may be used for convenience.9.2.6 Start the yarn takeup drive unit. Adjust the takeupspeed to between 20 and 100 mm/min (0.75 and 4.0 in./min).FIG. 2 Yarn-to-

48、Yarn Friction ApparatusCapstan MethodD34120739.2.7 After the mark (9.2.4) has passed completely throughthe intertwisted region and is on the output side above theinterwrapped region, measure the coefficient of friction or theinput and output tensions. Record the values until an additional100 mm (4 i

49、n.) of yarn has passed out of the interwrappedregion. If stick-slip is present, record ten consecutive maxi-mum values.9.3 Option 2 (Capstan Method):9.3.1 Using an auxiliary pulley above the mandrel, calibratethe apparatus by dead weight.9.3.2 Wrap enough yarn from the specimen onto the cylin-der to cover the surface.9.3.3 Transfer the yarn-wrapped cylinder to the frictionapparatus and hang a single strand of the same yarn over thecylinder, as shown in Fig. 2. For spun-staple yarns, use adouble strand to prevent the twist from backing out.9.3.