ASTM D4120-07(2012)
(Test Method)Standard Test Method for Fiber Cohesion in Roving, Sliver, and Top in Dynamic Tests
Standard Test Method for Fiber Cohesion in Roving, Sliver, and Top in Dynamic Tests
SIGNIFICANCE AND USE
This test method for the determination of cohesion in sliver, roving, or top in dynamic tests may be used for the acceptance testing of commercial shipments but caution is advised since information on between-laboratory precision is lacking. Comparative tests as directed in 5.1.1 may be advisable.
If there are differences or practical significance between reported test results for two laboratories (or more), comparative test should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, test samples that are as homogeneous as possible, drawn from the material from which the disparate test results were obtained, and randomly assigned in equal numbers to each laboratory for testing. The test results from the two laboratories should be compare using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.
The cohesive forces overcome in continuous drafting of slivers, rovings, or tops are affected by surface lubricants and such fiber properties as linear density, surface configuration, fiber length, fiber crimp, and fiber-frictional characteristics.
The concept of drafting is one of the most important principles in the production of yarn from fibrous raw stock.
The values of force to maintain drafting determined by this method are induced by mechanical means similar to those used in textile processing.
The attenuation of textile fiber strands while in motion closely approximates actual textile processing conditions, and the relative values of force may be used to predict processing behaviors.
Fiber cohesion is affected by the alignment of fiber in the textile strand and strand compaction in addition to the factors listed in 5.2. Although fibers are more nearly aligned in draw sliver than in car...
SCOPE
1.1 This test method describes the measurement of fiber cohesion as the dynamic cohesive force required to maintain drafting in rovings, slivers or tops when they are subjected to stress induced by passing between pairs of drafting rolls of different surface speeds. The cohesive force is converted to cohesive tenacity based on the linear density of the material.
Note 1—For static tests refer to Test Method D2612.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D4120 − 07 (Reapproved 2012)
Standard Test Method for
Fiber Cohesion in Roving, Sliver, and Top in Dynamic Tests
This standard is issued under the fixed designation D4120; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 The following terms are relevant to this standard:
cohesive force, fiber cohesion, roving, sliver, tenacity, top.
1.1 This test method describes the measurement of fiber
cohesion as the dynamic cohesive force required to maintain
3.2 For all other terms are related to textiles, refer to
drafting in rovings, slivers or tops when they are subjected to
Terminology D123.
stress induced by passing between pairs of drafting rolls of
different surface speeds. The cohesive force is converted to
4. Summary of Test Method
cohesive tenacity based on the linear density of the material.
4.1 This test method provides an indication of the ability of
NOTE 1—For static tests refer to Test Method D2612.
fibers to hold together by measuring the force required to slide
1.2 This standard does not purport to address all of the fibers in a direction parallel to their length. Specific lengths of
safety concerns, if any, associated with its use. It is the
roving, sliver, or top are drafted between two pairs of rollers,
responsibility of the user of this standard to establish appro- witheachpairmovingatadifferentperipheralspeed.Thedraft
priate safety and health practices and determine the applica-
forces are recorded. Test specimens are then weighed and the
bility of regulatory limitations prior to use. linear density calculated. Drafting tenacity, calculated as the
draft resisting force per unit linear density, is considered to be
2. Referenced Documents
a measure of the dynamic fiber cohesion.
2.1 ASTM Standards:
D123Terminology Relating to Textiles
5. Significance and Use
D519Test Method for Length of Fiber in Wool Top
5.1 This test method for the determination of cohesion in
D1440Test Method for Length and Length Distribution of
sliver, roving, or top in dynamic tests may be used for the
Cotton Fibers (Array Method)
acceptance testing of commercial shipments but caution is
D1447Test Method for Length and Length Uniformity of
advised since information on between-laboratory precision is
Cotton Fibers by Photoelectric Measurement
lacking. Comparative tests as directed in 5.1.1 may be advis-
D1575Test Method for Fiber Length of Wool in Scoured
able.
Wool and in Card Sliver
5.1.1 If there are differences or practical significance be-
D1776Practice for Conditioning and Testing Textiles
tween reported test results for two laboratories (or more),
D2258Practice for Sampling Yarn for Testing
comparativetestshouldbeperformedtodetermineifthereisa
D2612Test Method for Fiber Cohesion in Sliver and Top
statistical bias between them, using competent statistical assis-
(Static Tests)
tance.As a minimum, test samples that are as homogeneous as
D3333Practice for Sampling Manufactured Staple Fibers,
possible,drawnfromthematerialfromwhichthedisparatetest
Sliver, or Tow for Testing
resultswereobtained,andrandomlyassignedinequalnumbers
D4849Terminology Related to Yarns and Fibers
to each laboratory for testing. The test results from the two
3. Terminology
laboratories should be compare using a statistical test for
unpaired data, at a probability level chosen prior to the testing
3.1 For all terminology relating to D13.58, Yarns and
series. If a bias is found either its cause must be found and
Fibers, refer to Terminology D4849.
corrected, or future test results for that material must be
adjusted in consideration of the known bias.
ThistestmethodisunderthejurisdictionofASTMCommitteeD13onTextiles
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
5.2 The cohesive forces overcome in continuous drafting of
Current edition approved July 1, 2012. Published August 2012. Originally
slivers, rovings, or tops are affected by surface lubricants and
approved in 1982. Last previous edition approved in 2007 as D4120–07. DOI:
10.1520/D4120-07R12. such fiber properties as linear density, surface configuration,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
fiber length, fiber crimp, and fiber-frictional characteristics.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2.1 The concept of drafting is one of the most important
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. principles in the production of yarn from fibrous raw stock.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4120 − 07 (2012)
5.2.2 Thevaluesofforcetomaintaindraftingdeterminedby tainerinthelotsamplethenumberoflaboratorysamplingunits
this method are induced by mechanical means similar to those as directed in an applicable material specification or other
used in textile processing. agreement between purchaser and supplier such as an agree-
5.2.3 Theattenuationoftextilefiberstrandswhileinmotion ment to use Practice D3333 or Practice D2258. Preferably, the
closely approximates actual textile processing conditions, and same number of laboratory sampling units are taken from each
the relative values of force may be used to predict processing shipping container in the lot sample. If differing numbers of
behaviors. laboratory sampling units are to be taken from shipping
containers in the lot sample, determine at random which
5.3 Fiber cohesion is affected by the alignment of fiber in
shippingcontainersaretohaveeachnumberoflaboratoryunits
the textile strand and strand compaction in addition to the
drawn.
factorslistedin5.2.Althoughfibersaremorenearlyalignedin
7.2.1 Eachlaboratorysamplingunitshouldbeatleast100m
drawsliverthanincardsliver,thedrawsliverismorecompact.
long.
Thus,foragivenproductionrun,thedraftingforcesarehigher
for draw sliver than for card sliver. 7.3 Test Specimens— —From each laboratory sampling
unit, take one specimen. If the standard deviation determined
5.4 In addition to the aforementioned effects on drafting
for the laboratory sample is more than a value agreed upon
forces, the direction of specimen movement through drafting
between the purchaser and supplier, continue testing one
rollers may give different drafting force. Fibers in slivers may
specimen from each unit in the laboratory sample until the
have hooks of varying severity at one or both ends. Passage
standarddeviationforallspecimenstestedisnotmorethanthe
through drafting rollers results in higher drafting forces when
agreed to value or, by agreement, stop testing after a specified
the predominance of fiber hooks are oriented in the trailing
number.
mode of the strand.
8. Preparation and Calibration of Equipment
6. Apparatus and Materials
8.1 Install the tensiometer measuring head in the cohesion
6.1 Cohesion Meter, with rollers and controls for varying
meter. Selection of the proper capacity head may be deter-
drafts and rates of drafting.
mined by trial tests on the mate
...
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