1、Designation: D3937 12 (Reapproved 2018)Standard Test Method forCrimp Frequency of Manufactured Staple Fibers1This standard is issued under the fixed designation D3937; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 determination of the crimpfrequency of manufactured staple fibers. This test method isapplica
3、ble to all crimped staple fibers provided the crimp canbe viewed two-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 s
4、pun yarns may be different than 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
5、 tow samples) uses fiber chips 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 co
6、ncerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance wit
7、h internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards
8、:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2258 Practice for Sampling Yarn for TestingD3333 Practice for Sampling Manufactured Staple Fibers,Sliver, or Tow for TestingD4849 Terminology Related to Yarns and Fibers3. Terminology3.1 For all terminology r
9、elating to D13.58, Yarns andFibers, refer to Terminology D4849.3.1.1 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 D123.4. Summary of Test Method4.1 For Option One, a fiber specim
10、en of manufacturedstaple is placed on a short pile or plush 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 un
11、it of extended length.4.2 For Option Two, the number of crimps 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
12、is counted. The extended length of thespecimen is measured as 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 stap
13、le fibers may be used for theacceptance testing of commercial 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 result
14、s for two laboratories (or more),comparative tests should be 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 the1This test method is under the
15、 jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved July 1, 2018. Published August 2018. Originallyapproved in 1980. Last previous edition approved in 2007 as D3937 07(2012).DOI: 10.1520/D3937-12R18.2For r
16、eferenced 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, W
17、est Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World
18、Trade Organization Technical Barriers to Trade (TBT) Committee.1disparate test results were obtained, and randomly assigned inequal numbers to each laboratory for testing. The test resultsfrom the two laboratories should be compared using a statis-tical test for unpaired data, at a probability level
19、 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 in consideration of the known bias.5.2 This test method is used for quality control. It is anunsophisticated procedure which is particularly usefu
20、l in de-tecting major differences in crimp frequency. This test methodis not considered to be useful in research and developmentwhere minor differences or more complete crimpcharacterization, including amplitude and index, may be nec-essary.5.3 Crimp in fiber affects the carding and subsequentproces
21、sing of the fiber into either a yarn or a nonwoven fabric.5.4 Staple crimp in fiber will also affect the 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 und
22、er investigation.6.2 Magnifier, with no greater than 10 magnification,optional for counting crimp of fibers of low linear density inOption One or in measuring lengths.6.3 For Option Three:6.3.1 Projector, capable of a magnification of 10.6.3.2 Microscope Slides, 25 by 75 mm (1 by 3 in.).6.4 Specimen
23、 Board, covered with a short pile or plush.6.5 Tweezers, two pair.6.6 Scale, graduated in millimetres 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
24、 be-tween the purchaser and the supplier, such as an agreement touse Practice D3333 or Practice D2258. 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 variabilitybetw
25、een shipping units, between packages, ends, or other laboratorysampling unit within a shipping unit 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
26、 limiting quantity level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take 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 supp
27、lier such as anagreement to use Practice D3333 or Practice D2258.Preferably, the same number of laboratory sampling units aretaken from each shipping container in the lot sample. Ifdiffering numbers of laboratory sampling units are to be takenfrom shipping containers in the lot sample, determine atr
28、andom which shipping containers are to have each number oflaboratory units drawn.7.2.1 For Staple 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 un
29、it,take twenty-five specimens at random. For Options One andThree, each specimen is a fiber, 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
30、 ten specimens from the same laboratory samplingunit until the standard deviation for all specimens 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 D1776.9. Procedure9.1 Test conditio
31、ned specimens in the standard atmosphereas directed in Practice D1776.9.2 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,
32、 flatten each specimen with the crimpin a plane 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 pressur
33、e as in 9.2.1. Take care not todestroy the 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. Pro
34、ject the image onto a smooth white surface.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
35、50 mm (2in.). If fibers are longer than 50 mm, they may be cut toapproximately 50-mm lengths before counting the crimp.NOTE 2Low-power magnification, no greater than 10, may be usefulin counting the number of crimp units.NOTE 3Users of this test method should be aware of the fact thatcrimp configura
36、tion in a manufactured fiber is not always 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, removeD393
37、7 12 (2018)2a fiber from each chip, place these fibers on 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 option
38、s, place the scale on the specimen board.Grip one end of a 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
39、 tostretch the fiber.9.4.2.1 From the scale, read 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
40、mm (crimp per inch), using Eq 1 or Eq2:F 525CL(1)F 5CL(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
41、If requested, calculate the standard deviation 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 D3937 for crimp frequency. Describe the material orproduct
42、 sampled and the method of sampling used.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
43、or coefficient of variation, orboth, for 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 25observations, the diffe
44、rences should not exceed 1.15 crimps perinch in 95 out of 100 cases when all of the observations aretaken by the same well-trained operator using the same piece oftest equipment and specimens randomly drawn from thesample of material. Larger differences are likely to occur underall other circumstanc
45、es.12.2 Interlaboratory Test DataAn interlaboratory 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
46、results expressed as standard deviations 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 0.49
47、Between-laboratory component 2.35NOTE 4Where separate components of variance are shown formulti-material comparisons, (1) the multi-material, single-operator com-ponent is due to an operator times material (within-laboratories) interac-tion and is combined with the single-material, single-operator c
48、omponentin calculating critical differences, and (2) any increase in the multi-material, between-laboratory component over the single-material,between-operator component is due to a material times laboratoryFIG. 1 Standard Reference Chart for Crimp CountingD3937 12 (2018)3interaction.D3937 12 (2018)
49、412.3 PrecisionFor the components of variance reported in12.2, two averages of observed values should be consideredsignificantly 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 meaningful statement can be made abouttwo specific laboratories, the amount of statistical bias, if any, betweenthem must be established, with each
