ASTM D1425/D1425M-09
(Test Method)Standard Test Method for Unevenness of Textile Strands Using Capacitance Testing Equipment
Standard Test Method for Unevenness of Textile Strands Using Capacitance Testing Equipment
SIGNIFICANCE AND USE
This test method for the determination of evenness of textile strands is used extensively for acceptance testing of commercial shipments of filament or spun staple yarn, comber laps, roving, sliver, or tops. 6.2 6.3 6.4 6.5 Evenness values obtained on different instruments will be comparable for strands from the same sample provided the following parameters are the same in all cases: (1) the measure of evenness used; (2) the capacitive length zone L (see 3.1.5 and 3.1.5.1); (3) the sample length, Ls (see 3.1.8); (4) instrument test speed, (5) laboratory temperature and humidity conditions (see 12.1 and 12.1.1); and (6) test specimen variation. When different models of an instrument are used, and one or more of the six parameters are not identical, test results may differ.
Values of strand evenness are also used in quality control, process optimization, and together with yarn strength measurements, is the first appraisal of a strand's quality. A low evenness value is, in general, preferred. Higher evenness values generally indicate difficult spinning, lower yarn strength, and poorer fabric appearance. Experience has shown that the relationship of evenness to the prediction of yarn performance and to fabric appearance is not a simple one. An evenness value must, therefore, be used cautiously and be supplemented by additional evenness information, such as mid-term and long-term mass variations, thin, thick, and nep imperfection counts, diagram chart spectrogram chart, length variation curve, and histogram analyses.
Continuous filament yarns should be tested for mass variation on instruments specifically designed to them.; failure to do so will result in inaccurate test results. Further, low-twist, continuous yarns tend to flatten to a ribbon configuration while passing through the condenser of a capacitance instrument. These specific instruments are designed to insert false twist in the condenser during testing to overcome the flattening effect and may result in ...
SCOPE
1.1 This test method covers the indirect measurement of evenness (mass variation) of non-conductive textile strands, including top, comber lap, sliver, roving, and yarn produced from staple fibers and continuous filament yarns, by means of capacitance testing equipment.
1.2 Strands made from fiber blends can be tested using this test method only if the different fibers are uniformly distributed throughout the strand.
1.3 The test method provides numeric values for the measurement and evaluation of short-, mid-, and long-term mass variations of the tested strand in terms of frequently occurring faults classified as thin places, thick places, and neps and graphical representations of evenness values in the form of diagram charts, spectrograms, length variation curves, and histograms.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.5 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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Designation:D1425/D1425M–09
Standard Test Method for
Unevenness of Textile Strands Using Capacitance Testing
1
Equipment
This standard is issued under the fixed designation D1425/D1425M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D2258 Practice for Sampling Yarn for Testing
D4849 Terminology Related to Yarns and Fibers
1.1 This test method covers the indirect measurement of
evenness (mass variation) of non-conductive textile strands,
3. Terminology
including top, comber lap, sliver, roving, and yarn produced
3.1 Definitions:
from staple fibers and continuous filament yarns, by means of
3.1.1 electric constant, n—in textile capacitance testing,the
capacitance testing equipment.
change in the electrical field as measured by the sensors
1.2 Strands made from fiber blends can be tested using this
(capacitors) of an evenness instrument when a non-conductive
testmethodonlyifthedifferentfibersareuniformlydistributed
textile strand travels between capacitor plates.
throughout the strand.
3.1.1.1 Discussion—The dielectric change is measured as
1.3 The test method provides numeric values for the mea-
the ratio of the amount of stored energy between the capacitors
surement and evaluation of short-, mid-, and long-term mass
without a strand and during the movement of a strand through
variations of the tested strand in terms of frequently occurring
thesensorzoneandisindirectproportiontothemassvariation
faults classified as thin places, thick places, and neps and
that is output to a diagram chart.
graphical representations of evenness values in the form of
3.1.2 evenness, CV% (or U%), n— in textiles, the coeffi-
diagram charts, spectrograms, length variation curves, and
cient of mass variation derived from the standard deviation of
histograms.
the mass variation of a specified strand length (L ) over the
s
1.4 The values stated in either SI units or inch-pound units
mass variation (formerly known as unevenness).
are to be regarded separately as standard. The values stated in
3.1.2.1 Discussion—For strands with normal mass variation
each system may not be exact equivalents; therefore, each
distribution, the relationship between CV% and U% is U% is
system shall be used independently of the other. Combining
multiplied by 1.25. Although both CV% and U% are used as
values from the two systems may result in non-conformance
values of evenness, CV% is considered more accurate CV% is
with the standard.
gradually replacing U% as the only calculated measurement of
1.5 This standard does not purport to address all of the
evenness.
safety concerns, if any, associated with its use. It is the
3.1.3 imperfections, n—in textile evenness testing, the indi-
responsibility of the user of this standard to establish appro-
vidual number of thick places, thin places, and neps of a
priate safety and health practices and determine the applica-
sample strand length measured by a capacitive evenness tester
bility of regulatory limitations prior to use.
at selected sensitivity settings.
2. Referenced Documents 3.1.4 length between, L ,, n—in textile evenness testing, the
b
2 length of strand segments weighed to determine evenness for
2.1 ASTM Standards:
the direct method (cut & weigh) of measuring evenness.
D123 Terminology Relating to Textiles
3.1.5 length capacitance zone, L , n—, the width of the
c
D1776 Practice for Conditioning and Testing Textiles
measurement field of the capacitive sensor.
3.1.5.1 Discussion—The capacitive sensor measurement
1
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
field determines the length between the indirect method of
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
evennesstesting.TheLcisthelengthofstrandbeingmeasured
Current edition approved July 1, 2009. Published August 2009. Originally
between the sensing elements at any moment. L is analogous
approved in 1956. Discontinued May 2005 and reinstated as D1425/D1425M-09.
c
DOI: 10.1520/D1425_D1425M-09.
to L of the direct method.
b
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.6 mass variation, n—in textile evenness testing, the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
changes of the cross sectional mass along the length of a
Standards volume information, refer to the standard’s Document Summary page on
continuous strand or of a portion of a strand.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D1425–96 Designation:D1425/D1425M–09
Standard Test Method for
Unevenness of Textile Strands Using Capacitance Testing
1
Equipment
This standard is issued under the fixed designation D 1425/D1425M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1This test method covers the indirect measuring of unevenness of textile strands from tow, top, sliver, roving, and yarn
produced from staple fibers and filament yarns by means of continuous runs using capacitance testing equipment.
1.2The test method provides a value of “short-term unevenness,” a single value expressing the complicated strand property that
is unevenness.
1.3The test method is applicable to all yarns, rovings, slivers, and tops, except as indicated below.
1.3.1Low twist filament yarns should be tested only if additional twist is inserted during testing.
NOTE1—In many cases, low twist yarns tend to flatten to a ribbon while passing through the condenser of the instrument, and the recorded value of
unevenness is increased above the true value.
1.3.2Strands made from fiber blends should be tested only if blending is uniform along the strand.
NOTE2—Nonuniform blending may cause a higher reading of unevenness than the true value if the component fibers differ in dielectric constant. The
magnitude of the increase of unevenness readings due to nonuniform blending cannot be stated in general terms.
1.4The values stated in either acceptable metric units or in other units shall be regarded separately as standard.The values stated
in each system may not be exact equivalents; therefore, each system must be used independently of the other, without combining
values in any way.
1.1 This test method covers the indirect measurement of evenness (mass variation) of non-conductive textile strands, including
top,comberlap,sliver,roving,andyarnproducedfromstaplefibersandcontinuousfilamentyarns,bymeansofcapacitancetesting
equipment.
1.2 Strands made from fiber blends can be tested using this test method only if the different fibers are uniformly distributed
throughout the strand.
1.3 Thetestmethodprovidesnumericvaluesforthemeasurementandevaluationofshort-,mid-,andlong-termmassvariations
of the tested strand in terms of frequently occurring faults classified as thin places, thick places, and neps and graphical
representations of evenness values in the form of diagram charts, spectrograms, length variation curves, and histograms.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D 123 Terminology Relating to Textiles
D 1776 Practice for Conditioning and Testing Textiles
2
D 2258 Practice for Sampling Yarn for Testing Practice for Sampling Yarn for Testing
D 4849 Terminology Related to Yarns and Fibers
1
This test method is under the jurisdiction of ASTM Committee D-13 D13 on Textiles and is the direct responsibility of Subcommittee D13.58 on Yarn Test Methods,
General.
Current edition approved Feb. 10, 1996. Published April 1996. Originally published as D1425–56 T. Last previous edition D1425–89.on Yarns and Fibers.
Current edition approved July 1, 2009. Published August 2009. Originally approved in 1956. Last previous edition approved in 1996 12 D1425 – 96.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 07.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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D1425/D1425M–09
3. Terminology
3.1 Definitions:
3.1.1 coeffıcient of variation unevenness, CV%electricconstant, n—
...
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