ASTM D6612-00(2006)e1
(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.
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 (Reapproved 2006)
Standard Test Method for
Yarn Number and Yarn Number Variability Using Automated
Tester
This standard is issued under the fixed designation D6612; 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.
´ NOTE—Section 3 was updated editorially in August 2006.
1. Scope 3. Terminology
1.1 This test method covers the measurement of yarn 3.1 For all terminology relating to D13.58, Yarns and
number up to 4000 dtex (3600 denier) and related variability Fibers, refer to Terminology D4849.
properties of filament and spun yarns using an automated tester 3.1.1 The following terms are relevant to this standard:
with capability for measuring mass variability characteristics. cotton count, coefficient of variation, denier, linear density, tex,
1.2 Yarn number variability properties include percent den- yarn number, yarn numbering system, bad/good test, density
sity spread (%DS), coefficient of variation (%CV), density frequency variability, density spread.
frequency variation. 3.2 For all other textile terms used in this test method, see
Terminology D123.
NOTE 1—For determination of yarn number by use of reel and balance,
refer to Test Method D1907. For another method of measuring variability
4. Summary of Test Method
(unevenness) in yarn, refer to Test Method D1425.
4.1 A specified length of yarn (specimen) is stripped auto-
1.3 The values stated in either SI units or inch-pound units
matically directly from the package, cut, and weighed. The
are to be regarded separately as standard. Within the text, the
yarnnumberiscalculatedbyinterfacedcomputer,displayedon
inch-pound units are in parentheses. The values stated in each
a monitor, and may be printed. The yarn number can be
system are not exact equivalents; therefore, each system shall
reported in tex, denier, or cotton count units.
be used independently of the other. Combining values from the
4.2 Simultaneously, by means of a capacitance cell, the
two systems may result in inaccuracies of results.
massofthespecimenismeasuredinsubsectionsandfrequency
1.4 This standard does not purport to address all of the
of mass value crossovers are counted for calculation of
safety concerns, if any, associated with its use. It is the
variability properties: %DS, %CV, %BGT and %DFV.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 Test Method D6612 for yarn number and yarn number
variability is satisfactory for acceptance of commercial ship-
2. Referenced Documents
ments and is used in the trade.
2.1 ASTM Standards:
5.1.1 If there are differences of practical significance be-
D123 Terminology Relating to Textiles
tween the reported test results for two or more laboratories,
D1425 Test Method for Unevenness of Textile Strands
comparative tests should be performed by those laboratories to
Using Capacitance Testing Equipment
determine if there is a statistical bias between them, using
D1776 Practice for Conditioning and Testing Textiles
competent statistical assistance. As a minimum, samples used
D1907 Test Method for Linear Density of Yarn (Yarn
for each comparative tests should be as homogeneous as
Number) by the Skein Method
possible, drawn from the same lot of material as the samples
D2258 Practice for Sampling Yarn for Testing
that results in disparate results during initial testing, and
D4849 Terminology Related to Yarns and Fibers
randomly assigned in equal numbers to each laboratory. Other
fabrics with established tests values are used for this purpose.
This test method is under the jurisdiction ofASTM Committee D13 onTextiles The test results from the laboratories involved should be
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
compared appropriate statistical analysis and a probability
Current edition approved June 1, 2006. Published August 2006. Originally
level chosen by the two parties before testing begins, at a
approved in 2000. Last previous edition approved in 2000 as D6612–00. DOI:
probability level chosen prior to the testing series. If a bias is
10.1520/D6612-00R06E01.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
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D6612–00 (2006)
found, either its cause must be found and corrected, or future 6.2.1 Low (9.7-mm slit), up to 30 dtex (up to 27 denier).
test results adjusted in consideration of the known bias. 6.2.2 Medium (1.2-mm slit), 31–239 dtex (25–215 denier).
5.1.2 The average results from the two laboratories should
6.2.3 High (2.2-mm slit), 240–1333 dtex (216–1200 denier).
be compared using appropriate statistical analysis and a prob-
6.2.4 Ultra-High (3.2-mm slit), 1334–4000 dtex
ability level chosen by the two parties before the testing is
(1201–3600 denier).
begun. If a bias is found, either its cause must be found and
6.3 Calibration Weights, 2-g and others as needed to cover
corrected or the purchaser and the supplier must agree to
the tex (denier) ranges of interest.
interpret future test results with consideration to the known
bias.
7. Sampling
5.2 Test Method D6612 also is used for the quality control
7.1 Lot Sample—As a lot sample for acceptance testing,
of filament yarns.
take at random the number of shipping units directed in an
5.3 Indices of Variability:
applicable material specification or other agreement between
5.3.1 Coeffıcient of Variation—%CVis a standard statistical
the purchaser and the supplier, such as an agreement to use
calculation and is the most common index of yarn unevenness.
Practice D2258. Consider shipping cases or other shipping
For most textile applications in the 80–330 dtex (70–300
units to be the primary sampling units.
denier) range, a 1.0–1.3 %CV is adequate. %CV of yarns
NOTE 2—An adequate specification or other agreement between the
coarser than 666 dtex (600 denier) is not routine and usually
purchaser and the supplier requires taking into account the variability
not meaningful. %CV is less discriminating that %DS.
between shipping units, between packages or ends within a shipping unit,
5.3.2 Bad/Good Test—%BGT, which will normally be up to
and between specimens from a single package to provide a sampling plan
20 % greater than %DS value, emphasizes the greatest spread
with a meaningful producer’s risk, consumer’s risk, acceptable quality
in the entire length tested, (%DS is an average). If the value is
level, and limiting quality level.
greaterthan50 %ofthe%DS,itsuggeststhatthereisaprocess
7.2 Laboratory Sample—As a laboratory sample for accep-
that needs to be investigated.
tance testing, take at random from each shipping unit in the lot
5.3.3 Density Spread—%DS is equivalent to the Uster %
sample the number of packages directed in an applicable
unevenness (Test Method D1425) and is an indication of
material specification or other agreement between the pur-
short-term variability. Yarns with extreme values are more
chaser and the supplier, such as an agreement to use Practice
likely to cause trouble in subsequent yarn processes, which
D2258. Preferably, the same number of packages should be
makes this perhaps the most useful index. The minimum
taken from each shipping unit in the lot sample. If differing
achievable and maximum tolerance spread for a yarn product
numbers of packages are to be taken from shipping units in the
will depend on the yarn manufacturing process and end use.A
lot sample, determine at random, which shipping units are to
spread of 3–4 % generally is,
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