ASTM_D_3937_-_12.pdf

Designation:D393712Standard 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 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 determination of the crimpfrequency of manufactured staple fibers.This test method isapplicable 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 spun 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 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 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: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 relating 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 specimen 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 unit 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 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 staple 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 results 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 thedisparate 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 chosen prior1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 1980.Last previous edition approved in 2007 as D3937 07.DOI:10.1520/D3937-12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 to 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 useful in de-tecting major differences in crimp frequency.T