1、Designation: D 3937 07Standard Test Method forCrimp Frequency of manufactured Staple Fibers1This standard is issued under the fixed designation D 3937; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in 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 determination of the crimpfrequency of manufactured staple fibers. This test method isapplicable to all crim
3、ped provided the crimp can be viewedtwo-dimensionally as a sine-wave configuration.1.1.1 It should be recognized that yarn manufacturing pro-cesses or treatments to manufactured yarns can influence ormodify crimp in fiber. Hence, the value for crimp of fiberstaken from spun yarns may be different th
4、an that of the samefiber prior to the manufacturing or treatment processes.1.2 Three options are provided for preparation of the speci-mens. Option One (preferred) uses single fibers for the speci-mens with a low magnification available, Option Two (optionalfor staple or tow samples) uses fiber chip
5、s as the specimens,and Option Three uses projected images of single fibers.1.3 The values stated in SI units are to be regarded as thestandard. The inch-pound units in parentheses are for informa-tion only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated wi
6、th 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:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditio
7、ning and Testing TextilesD 2258 Practice for Sampling Yarn for TestingD 3333 Practice for Sampling Manufactured Staple Fibers,Sliver, or Tow for TestingD 4849 Terminology Relating to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns andFibers, refer to Terminology D 484
8、9.3.1.1 The following terms are relevant to this standard:crimp. crimp frequency, crimp index, fiber chip.3.2 For all other terms are related to textiles, refer toTerminology D 123.4. Summary of Test Method4.1 For Option One, a fiber specimen of manufacturedstaple is placed on a short pile or plush
9、surface. The crimpsalong the entire length of the specimen is counted. After thespecimen is counted, the fiber is straightened without defor-mation and its uncrimped length measured. Crimp frequency isreported as the number of crimps per unit of extended length.4.2 For Option Two, the number of crim
10、ps is counted infiber chip specimens. The specimen length is measured onfibers taken from each of the chips.4.3 For Option Three, the fiber specimen is mounted be-tween microscope slides. The image of the specimen isprojected and its crimp is counted. The extended length of thespecimen is measured a
11、s in Option One.4.4 In each option, the crimp frequency is calculated fromthe numbers of crimp counted and the fiber lengths measured.5. Significance and Use5.1 This test method for the determination of crimp fre-quency of manufactured staple fibers may be used for theacceptance testing of commercia
12、l shipments but caution isadvised since between-laboratory precision is known to bepoor. Comparative tests conducted as directed in 5.1.1 may beadvisable.5.1.1 If there are differences or practical significance be-tween reported test results for two laboratories (or more),comparative tests should be
13、 performed to determine if there isa statistical bias between them, using competent statisticalassistance. As a minimum, test samples that are as homoge-neous as possible, drawn from the material from which thedisparate test results were obtained, and randomly assigned inequal numbers to each labora
14、tory for testing. The test resultsfrom the two laboratories should be compared using a statis-tical test for unpaired data, at a probability level chosen priorto testing series. If a bias is found, either its cause must befound and corrected, or future test results for that material mustbe adjusted
15、in consideration of the known bias.1This 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 in 1980. Last previous edition
16、 approved in 2001 as D 3937 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 website.1Copyright ASTM International,
17、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 This test method is used for quality control. It is anunsophisticated procedure which is particularly useful in de-tecting major differences in crimp frequency. This test methodis not considered to be useful in
18、research and developmentwhere minor differences or more complete crimp characteriza-tion, including amplitude and index, may be necessary.5.3 Crimp in fiber affects the carding and subsequentprocessing of the fiber into either a yarn or a nonwoven fabric.5.4 Staple crimp in fiber will also affect th
19、e bulk oropenness of a yarn and therefore the hand and visual appear-ance of the finished textile product.6. Apparatus6.1 Short Pile or Plush Surface, of a color contrasting withcolor of fibers under investigation.6.2 Magnifier, with no greater than 103 magnification,optional for counting crimp of f
20、ibers of low linear density inOption One or in measuring lengths.6.3 For Option Three:6.3.1 Projector, capable of a magnification of 103.6.3.2 Microscope Slides, 25 by 75 mm (1 by 3 in.).6.4 Specimen Board, covered with a short pile or plush.6.5 Tweezers, two pair.6.6 Scale, graduated in millimetres
21、 or116-in. units.7. Sampling7.1 Lot samplingAs a lot sample for acceptance testing,take at random the number of shipping containers directed inthe applicable material specification or other agreement be-tween the purchaser and the supplier, such as an agreement touse Practice D 3333 or Practice D 22
22、58. Consider shippingcontainers to be the primary sampling units.NOTE 1An adequate specification or other agreement between thepurchaser or the supplier requires taking into account the variabilitybetween shipping units, between packages, ends, or other laboratorysampling unit within a shipping unit
23、 if applicable, and within specimensfrom a single package, end or other laboratory sampling unit to provide asampling plan with a meaningful producers risk, consumers risk,acceptable quality level, and limiting quantity level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take
24、at random from each shipping container inthe lot sample the number of laboratory sampling units asdirected in an applicable material specification or other agree-ment between the purchaser and the supplier such as anagreement to use Practice D 3333 or Practice D 2258. Prefer-ably, the same number of
25、 laboratory sampling units are takenfrom each shipping container in the lot sample. If differingnumbers of laboratory sampling units are to be taken fromshipping containers in the lot sample, determine at randomwhich shipping containers are to have each number of labora-tory units drawn.7.2.1 For St
26、aple FiberTake 50-g samples from laboratorysampling units.7.2.2 For Sliver (or Top) or TowTake 1 m from theleading end which has a clean, uniform appearance.7.3 Test SpecimensFrom each laboratory sampling unit,take twenty-five specimens at random. For Options One andThree, each specimen is a fiber,
27、and for Option Two, thespecimen is a fiber chip. If the standard deviation determinedfor the ten specimens is more than a value agreed uponbetween the purchaser and the supplier, continue testing ingroups of ten specimens from the same laboratory samplingunit until the standard deviation for all spe
28、cimens tested is notmore than the agreed to value or, by agreement, stop testingafter a specified number.8. Conditioning8.1 Condition the specimens as directed in Practice D 1776.9. Procedure9.1 Test conditioned specimens in the standard atmospherefor testing textiles, which is 21 6 1C (70 6 2F) and
29、 65 62 % relative humidity.9.2 Specimen Preparation Options:9.2.1 Option One Single Fiber (Preferred)Carefully re-move 25 fibers at random from each laboratory sampling unit,using tweezers. Place these specimens on a specimen board.Using fingertip pressure, flatten each specimen with the crimpin a p
30、lane parallel with the board. Take care not to destroy thecrimp.9.2.2 Option Two Fiber ChipCarefully remove 25 fiberchips at random from each laboratory sampling unit usingtweezers. Place these specimens on a specimen board andflatten with fingertip pressure as in 9.2.1. Take care not todestroy the
31、crimp.9.2.3 Option Three Fiber ProjectionCarefully remove 25fiber at random from each laboratory sampling unit, usingtweezers. Place these specimens on microscope slides withoutdisturbing the crimp. Place the prepared slide on the stage ofthe projector. Project the image onto a smooth white surface.
32、9.3 Counting Crimp:9.3.1 For all options, count and record the number of crimpunits along the entire length of the specimen (see Fig. 1). Noteany gross differences observed in crimp distribution or even-ness.9.3.2 Where possible count the crimp in at least 50 mm (2in.). If fibers are longer than 50
33、mm, they may be cut toapproximately 50-mm lengths before counting the crimp.NOTE 2Low-power magnification, no greater than 103, may beuseful in counting the number of crimp units.NOTE 3Users of this test method should be aware of the fact thatcrimp configuration in a manufactured fiber is not always
34、 uniform over thelength of the fiber.9.4 Measuring Fiber Length:9.4.1 For all options, hold one end of the fiber with a fingerof one hand and gently straighten the fiber with the other hand.Be careful not to stretch the fiber. If Option 2 is used, removea fiber from each chip, place these fibers on
35、a specimen boardand measure the lengths as being representative of the chips. IfOption 3 is used, transfer fiber from the slide to the pile orplush surface to measure the extended length. Do not measurethe projected image.9.4.2 For all options, place the scale on the specimen board.Grip one end of a
36、 fiber near the tip with tweezers and hold thetip of the fiber aligned with the zero on the scale. Then, grip theother end of the fiber near its tip with a second pair of tweezersand gently straighten the fiber along the scale. Be careful not tostretch the fiber.D39370729.4.2.1 From the scale, read
37、the extended specimen lengthto the nearest 1 mm (116 in.).9.5 Continue counting and measuring as directed in 9.3 and9.4 to test the remaining specimens.10. Calculation10.1 Calculate the crimp frequency of each specimen to thenearest 0.1 crimp per 25 mm (crimp per inch), using Eq 1 or Eq2:F 5 C 3 25/
38、L (1)F 5 C/L (2)where:F = crimp frequency, crimp/25 mm (crimp/1 in.),C = number of crimps counted, andL = extended length of the crimp-counted segment, mm(in.).10.2 Calculate the average crimp frequency for each labo-ratory sampling unit and for the lot.10.3 If requested, calculate the standard devi
39、ation or coef-ficient of variation, or both, for each laboratory sampling unitand for the lot sample container and the lot.11. Report11.1 State that the specimens were tested as directed in TestMethod D 3937 for crimp frequency. Describe the material orproduct sampled and the method of sampling used
40、.11.2 Report the following information:11.2.1 Average crimp frequency for each lot sample con-tainer tested and for each laboratory sampling unit and for thelot.11.2.2 Any gross differences in crimp configuration unifor-mity observed,11.2.3 Standard deviation or coefficient of variation, orboth, for
41、 the lot sample container and for each laboratorysampling unit and for the lot, if calculated.11.2.4 The specimen preparation option used, and11.2.5 Magnification, if used.12. Precision and Bias12.1 SummaryIn comparing two averages of 25 observa-tions, the differences should not exceed 1.15 crimps p
42、er inch in95 out of 100 cases when all of the observations are taken bythe same well-trained operator using the same piece of testequipment and specimens randomly drawn from the sample ofmaterial. Larger differences are likely to occur under all othercircumstances.12.2 Interlaboratory Test DataAn in
43、terlaboratory test wasrun in 1980 in which randomly drawn samples of five materialswere tested in each of six laboratories. Each laboratory usedtwo operators, each of whom tested 25 specimens of eachmaterial. The components of variance for crimps per unitlength results expressed as standard deviatio
44、ns were calculatedto be as follows:Crimps per InchSingle-material comparisons:Single-operator component 2.07Within-laboratory component 0.49Between-laboratory component 1.90Multi-material comparisons:Single-operator component 0.78Within-laboratory component 0.49Between-laboratory component 2.35NOTE
45、4Where separate components of variance are shown for multi-material comparisons, (1) the multi-material, single-operator component isdue to an operator times material (within-laboratories) interaction and iscombined with the single-material, single-operator component in calcu-lating critical differe
46、nces, and (2) any increase in the multi-material,between-laboratory component over the single-material, between-operatorcomponent is due to a material times laboratory interaction.12.3 PrecisionFor the components of variance reported in12.2, two averages of observed values should be consideredsignif
47、icantly different at the 95 % probability level if thedifference equals or exceeds critical differences as shown inTable 1.NOTE 5The tabulated values of the critical differences should beconsidered to be a general statement. Particularly with respect to between-laboratory precision. Before a meaning
48、ful statement can be made abouttwo specific laboratories, the amount of statistical bias, if any, betweenthem must be established, with each comparison being based on recentdata obtained on randomized specimens from one sample of the materialto be tested.FIG. 1 Standard Reference Chart for Crimp Cou
49、ntingD393707312.4 BiasThe value of crimps per unit length can bedefined only in terms of a specific test method. Within thislimitation, this test method for testing crimp frequency has noknown bias.13. Keywords13.1 crimp; textile fibersASTM 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 determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibil
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