1、Designation:D412007(Reapproved 2012)Standard Test Method forFiber Cohesion in Roving,Sliver,and Top in Dynamic Tests1This standard is issued under the fixed designation D4120;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year o
2、f 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 describes the measurement of fibercohesion as the dynamic cohesive force required to maintaindrafting in
3、 rovings,slivers or tops when they are subjected tostress induced by passing between pairs of drafting rolls ofdifferent surface speeds.The cohesive force is converted tocohesive tenacity based on the linear density of the material.NOTE1For static tests refer to Test Method D2612.1.2 This standard d
4、oes 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 Standa
5、rds:2D123 Terminology Relating to TextilesD519 Test Method for Length of Fiber in Wool TopD1440 Test Method for Length and Length Distribution ofCotton Fibers(Array Method)D1447 Test Method for Length and Length Uniformity ofCotton Fibers by Photoelectric MeasurementD1575 Test Method for Fiber Lengt
6、h of Wool in ScouredWool and in Card SliverD1776 Practice for Conditioning and Testing TextilesD2258 Practice for Sampling Yarn for TestingD2612 Test Method for Fiber Cohesion in Sliver and Top(Static Tests)D3333 Practice for Sampling Manufactured Staple Fibers,Sliver,or Tow for TestingD4849 Termino
7、logy 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:cohesive force,fiber cohesion,roving,sliver,tenacity,top.3.2 For all other terms are related to textiles,refer to
8、Terminology D123.4.Summary of Test Method4.1 This test method provides an indication of the ability offibers to hold together by measuring the force required to slidefibers in a direction parallel to their length.Specific lengths ofroving,sliver,or top are drafted between two pairs of rollers,with e
9、ach pair moving at a different peripheral speed.The draftforces are recorded.Test specimens are then weighed and thelinear density calculated.Drafting tenacity,calculated as thedraft resisting force per unit linear density,is considered to bea measure of the dynamic fiber cohesion.5.Significance and
10、 Use5.1 This test method for the determination of cohesion insliver,roving,or top in dynamic tests may be used for theacceptance testing of commercial shipments but caution isadvised since information on between-laboratory precision islacking.Comparative tests as directed in 5.1.1 may be advis-able.
11、5.1.1 If there are differences or practical significance be-tween reported test results for two laboratories(or more),comparative test should be performed to determine if there is astatistical bias between them,using competent statistical assis-tance.As a minimum,test samples that are as homogeneous
12、 aspossible,drawn from the material from which the disparate testresults were obtained,and randomly assigned in equal numbersto each laboratory for testing.The test results from the twolaboratories should be compare using a statistical test forunpaired data,at a probability level chosen prior to the
13、 testingseries.If a bias is found either its cause must be found andcorrected,or future test results for that material must beadjusted in consideration of the known bias.5.2 The cohesive forces overcome in continuous drafting ofslivers,rovings,or tops are affected by surface lubricants andsuch fiber
14、 properties as linear density,surface configuration,fiber length,fiber crimp,and fiber-frictional characteristics.5.2.1 The concept of drafting is one of the most importantprinciples in the production of yarn from fibrous raw stock.1This test method is under the jurisdiction ofASTM Committee D13 on
15、Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved July 1,2012.Published August 2012.Originallyapproved in 1982.Last previous edition approved in 2007 as D4120 07.DOI:10.1520/D4120-07R12.2For referenced ASTM standards,visit the ASTM website,w
16、ww.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 5.2.2 The values of force to maintain drafting determined bythis method are induced by mechanical means similar to thoseused in textile processing.5.2.3 The attenuation of textile fiber strands while in motioncl
