ASTM D6612-00
(Test Method)Standard Test Method for Yarn Number and Yarn Number Variability Using Automated Tester
Standard Test Method for Yarn Number and Yarn Number Variability Using Automated Tester
SCOPE
1.1 This test method covers the measurement of yarn number up to 4000 dtex (3600 denier) and related variability properties of filament and spun yarns using an automated tester with capability for measuring mass variability characteristics.
1.2 Yarn number variability properties include percent density spread (%DS), coefficient of variation (%CV), density frequency variation.Note 1—For determination of yarn number by use of reel and balance, refer to Test Method D 1907. For another method of measuring variability (unevenness) in yarn, refer to Test Method D 1425.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are in parentheses. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in inaccuracies of results.
1.4 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:D6612–00
Standard Test Method for
Yarn Number and Yarn Number Variability Using Automated
Tester
This standard is issued under the fixed designation D 6612; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 cotton count, n—an indirect yarn numbering system
generally used in the cotton system equal to the number of
1.1 This test method covers the measurement of yarn
840-yd, lengths of yarn/lb.
number up to 4000 dtex (3600 denier) and related variability
3.1.2 coeffıcient of variation (CV), n—a measure of the
properties of filament and spun yarns using an automated tester
dispersion of observed values equal to the standard deviation
with capability for measuring mass variability characteristics.
for the values divided by the average of the values; may be
1.2 Yarn number variability properties include percent den-
expressed as a percentage of the average (%CV).
sity spread (%DS), coefficient of variation (%CV), density
3.1.3 denier, n—the unit of linear density, equal to the mass
frequency variation.
in g/9000-m of fiber, yarn or other textile strand, that is used in
NOTE 1—For determination of yarn number by use of reel and balance,
a direct yarn numbering system.
refer toTest Method D 1907. For another method of measuring variability
3.1.4 linear density, n—mass per unit length.
(unevenness) in yarn, refer to Test Method D 1425.
3.1.5 tex, n—the unit of linear density, equal to the mass in
1.3 The values stated in either SI units or inch-pound units
g/1000-m of fiber, yarn or other textile strand, that is used in a
are to be regarded separately as standard. Within the text, the
direct numbering system.
inch-pound units are in parentheses. The values stated in each
3.1.6 yarn number, n—a measure of the linear density of a
system are not exact equivalents; therefore, each system shall
yarn, expressed as “mass per unit length” or “length per unit
be used independently of the other. Combining values from the
mass,” depending on the yarn numbering system.
two systems may result in inaccuracies of results.
3.1.7 yarn numbering system, n—a system expressing the
1.4 This standard does not purport to address all of the
size of a yarn as a relationship between its length and
safety concerns, if any, associated with its use. It is the
associated mass (see also yarn number, direct yarn numbering
responsibility of the user of this standard to establish appro-
system, and indirect yarn numbering system).
priate safety and health practices and determine the applica-
3.2 Definitions of Terms Specific to This Standard:
bility of regulatory limitations prior to use.
3.2.1 bad/good test (%BGT), n—an index value which
shows the total spread, or greatest variation, for the test;
2. Referenced Documents
mathematically, the difference between the highest and lowest
2.1 ASTM Standards:
massreadingsdeterminedinthetest,expressedasapercentage
D 123 Terminology Relating to Textiles
of the average mass.
D 1425 Test Method for Unevenness of Textile Strands
3.2.2 density frequency variability (DFV), n—an index of
Using Capacitance Testing Equipment
the spacing of irregularities; mathematically, the number of
D 1776 Practice for Conditioning Textiles for Testing
times the measured mass crosses over the mean mass line from
D 1907 Test Method for Yarn Number by the Skein
higher-to-lower values or lower-to-higher values divided by
Method
the distance over which the count is made.
D 2258 Practice for Sampling Yarn for Testing
3.2.3 density spread (%DS), n—a value which indicates the
degree to which the mass varies from its average; mathemati-
3. Terminology
cally, the average of the differences between the maximum and
3.1 Definitions—Terms used in this test method are defined
minimum values within specified subsections, expressed as a
in accordance with Terminology D 123.
percent based on an overall average.
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
and is the direct responsibility of Subcommittee D13.58 on Yarn Test Methods.
Current edition approved Nov. 10, 2000. Published February 2001.
Annual Book of ASTM Standards, Vol 07.01.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
D6612
4. Summary of Test Method will depend on the yarn manufacturing process and end use.A
spread of 3–4 % generally is, for most textile applications, in
4.1 A specified length of yarn (specimen) is stripped auto-
the range of 160–550 dtex (150 to 500 deniers). More critical
matically directly from the package, cut, and weighed. The
applications,suchasthoseusingfineryarns,mayrequirelower
yarnnumberiscalculatedbyinterfacedcomputer,displayedon
values.
a monitor, and may be printed. The yarn number can be
5.3.4 Density Frequency Variability—DFV is an index of
reported in tex, denier, or cotton count units.
spacingvariability,whereastheothersareindicesofmagnitude
4.2 Simultaneously, by means of a capacitance cell, the
or unevenness. Frequency variability can induce resonance in
massofthespecimenismeasuredinsubsectionsandfrequency
high-speed processing and is a common source of barre, dye
of mass value crossovers are counted for calculation of
streaks, or patterned unevenness in fabrics.
variability properties: %DS, %CV, %BGT and %DFV.
6. Apparatus
5. Significance and Use
6.1 Automatic Yarn Numbering Instrument
5.1 Test Method D 6612 for yarn number and yarn number
(ACW), (automatic-cut-and-weigh) ACW with interfaced
variability is satisfactory for acceptance of commercial ship-
computer (see Fig. 1)
ments and is used in the trade.
6.2 Density Variability Accessory (DVA), with yarn num-
5.1.1 If there are differences of practical significance be-
ber ranges:
tween the reported test results for two or more laboratories,
6.2.1 Low (9.7-mm slit), up to 30 dtex (up to 27 denier).
comparative tests should be performed by those laboratories to
6.2.2 Medium (1.2-mm slit), 31–239 dtex (25–215 denier).
determine if there is a statistical bias between them, using
6.2.3 High (2.2-mm slit), 240–1333 dtex (216–1200 denier).
competent statistical assistance. As a minimum, samples used
6.2.4 Ultra-High (3.2-mm slit), 1334–4000 dtex
for each comparative tests should be as homogeneous as
(1201–3600 denier).
possible, drawn from the same lot of material as the samples
6.3 Calibration Weights, 2-g and others as needed to cover
that results in disparate results during initial testing, and
the tex (denier) ranges of interest.
randomly assigned in equal numbers to each laboratory. Other
fabrics with established tests values are used for this purpose.
7. Sampling
The test results from the laboratories involved should be
7.1 Lot Sample—As a lot sample for acceptance testing,
compared appropriate statistical analysis and a probability
take at random the number of shipping units directed in an
level chosen by the two parties before testing begins, at a
applicable material specification or other agreement between
probability level chosen prior to the testing series. If a bias is
the purchaser and the supplier, such as an agreement to use
found, either its cause must be found and corrected, or future
Practice D 2258. Consider shipping cases or other shipping
test results adjusted in consideration of the known bias.
units to be the primary sampling units.
5.1.2 The average results from the two laboratories should
be compared using appropriate statistical analysis and a prob- NOTE 2—An adequate specification or other agreement between the
purchaser and the supplier requires taking into account the variability
ability level chosen by the two parties before the testing is
between shipping units, between packages or ends within a shipping unit,
begun. If a bias is found, either its cause must be found and
and between specimens from a single package to provide a sampling plan
corrected or the purchaser and the supplier must agree to
with a meaningful producer’s risk, consumer’s risk, acceptable quality
interpret future test results with consideration to the known
level, and limiting quality level.
bias.
7.2 Laboratory Sample—As a laboratory sample for accep-
5.2 Test Method D 6612 also is used for the quality control
tance testing, take at random from each shipp
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