ASTM D1577-96
(Test Method)Standard Test Methods for Linear Density of Textile Fibers
Standard Test Methods for Linear Density of Textile Fibers
SCOPE
1.1 These test methods cover the measurement of mass per unit length (linear density) of textile fibers and filaments. Direct weighing and vibroscope procedures with modifications for crimped and uncrimped fibers are included. The options and sections are listed below. OptionSectionsA—Fiber Bundle Weighing7-15B—Single-Fiber Weighing16-23C—Vibroscope, General24-3035 and 36C1—Uncrimped Fibers31 and 32C2—Crimped Fibers33 and 34Precision and Bias37 and 38
Note 1—For linear density of short lengths of yarn, refer to Test Method D 1059. For cotton linear density, refer to Test Methods D 1769, and D 2480. For measurement of wool diameter, refer to Test Methods D 1282, D 2130 and D 3510.
1.2 The crimp, taper and cross-sectional shape of the fiber may influence the linear density measured by single-fiber weighing and vibroscope.
1.3 These test methods measure the linear density of fibers with moisture in equilibrium with the standard atmosphere for testing textiles. The fiber moisture under these conditions is not necessarily the same as the commercial moisture regain for the fibers.
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 are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
1.5This 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: D 1577 – 96
Standard Test Methods for
Linear Density of Textile Fibers
This standard is issued under the fixed designation D 1577; 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 D 123 Terminology Relating to Textiles
D 629 Test Methods for Quantitative Analysis of Textiles
1.1 These test methods cover the measurement of mass per
D 1059 Test Method for Yarn Number Based on Short-
unit length (linear density) of textile fibers and filaments.
Length Specimens
Direct weighing and vibroscope procedures with modifications
D 1282 Test Method for Resistance to Airflow as an Indi-
for crimped and uncrimped fibers are included. The options
cation of Average Fiber Diameter of Wool Top, Card
and sections are listed below.
Sliver, and Scoured Wool
Option Sections
D 1769 Test Method for Linear Density of Cotton Fibers
A—Fiber Bundle Weighing 7-15
(Array Sample)
B—Single-Fiber Weighing 16-23
D 1776 Practice for Conditioning Textiles for Testing
C—Vibroscope, General 24-30
D 1907 Test Method for Yarn Number by the Skein
35 and 36
C1—Uncrimped Fibers 31 and 32
Method
C2—Crimped Fibers 33 and 34
D 2130 Test Method for Diameter of Wool and Other
Precision and Bias 37 and 38
Animal Fibers by Microprojection
NOTE 1—For linear density of short lengths of yarn, refer to Test
D 2257 Test Method for Extractable Matter in Textiles
Method D 1059. For cotton linear density, refer to Test Methods D 1769,
D 2258 Practice for Sampling Yarn for Testing
and D 2480. For measurement of wool diameter, refer to Test Methods
D 2480 Test Method for Maturity Index and Linear Density
D 1282, D 2130 and D 3510.
of Cotton Fibers by the Causticaire Method
1.2 The crimp, taper and cross-sectional shape of the fiber
D 2904 Practice for Interlaboratory Testing of a Textile Test
may influence the linear density measured by single-fiber
Method That Produces Normally Distributed Data
weighing and vibroscope.
D 3333 Practice for Sampling Man-Made Staple Fibers,
1.3 These test methods measure the linear density of fibers
Sliver, or Tow for Testing
with moisture in equilibrium with the standard atmosphere for
D 3510 Test Method for Diameter of Wool and Other
testing textiles. The fiber moisture under these conditions is not
Animal Fibers by Image Analyser
necessarily the same as the commercial moisture regain for the
D 3818 Test Method for Linear Density and Maturity Index
fibers.
of Cotton Fibers (IIC-Shirley Fineness/Maturity Tester)
1.4 The values stated in either SI units or inch-pound units
D 5103 Test Method for Length and Length Distribution of
are to be regarded separately as standard. The values stated in
Man-Made Staple Fibers (Single-Fiber Test)
each system are not exact equivalents; therefore, each system
2.2 ASTM Adjuncts:
shall be used independently of the other. Combining values
TEX-PAC
from the two systems may result in nonconformance with the
specification.
3. Terminology
1.5 This standard does not purport to address all of the
3.1 Definitions:
safety concerns, if any, associated with its use. It is the
3.1.1 effective fiber length—in the vibroscope test for linear
responsibility of the user of this standard to establish appro-
density, that portion of the fiber free to vibrate between fixed
priate safety and health practices and determine the applica-
supports.
bility of regulatory limitations prior to use.
3.1.2 fundamental resonant frequency—in linear density
testing, the lowest frequency at which free oscillations can
2. Referenced Documents
exist in a fiber tensioned between two fixed points.
2.1 ASTM Standards:
3.1.3 linear density, n—mass per unit length.
3.1.3.1 Discussion—The preferred units of measurement
These test methods are under the jurisdiction of ASTM Committee D-13 on
Textiles and are the direct responsibility of Subcommittee D13.57 on Fiber Test
Methods, General.
Annual Book of ASTM Standards, Vol 07.01.
Current edition approved Sept. 10, 1996. Published December 1996. Originally
Annual Book of ASTM Standards, Vol 07.02.
published as D 1577 – 58 T. Last previous edition D 1577 – 90.
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Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1577
are grams and metres, or multiples or submultiples of these. tension tests and adjustment of the data obtained for the linear
The tex unit, grams per kilometre, is recommended for yarns. density of the test specimen. These options offer advantages in
In these methods the linear density of the fibers is calculated in accuracy and ease of operations over calculation from specific
decitex (dtex) units; which are tex units multiplied by 1000 gravity and microscopically measured cross-sectional area.
millitex (mtex). 4.7 Additional information specific to Option C is in Section
3.1.4 tex—the unit of linear density; equal to the mass in 26.
grams of 1000 meters of fiber, yarn, or other textile strand, that
5. Sampling
is used in a direct yarn numbering system.
3.1.5 For definitions of other textile terms used in these 5.1 Lot Sampling—As a lot sample for acceptance testing,
methods, refer to Terminology D 123. take at random the number of shipping containers directed in
the applicable material specification or other agreement be-
4. Significance and Use
tween the purchaser and supplier, such as an agreement to use
Practice D 3333 or Practice D 2258, as applicable. Consider
4.1 Option A for bundle weighing of Test Method D 1577 is
shipping containers to be the primary sampling units.
used in the trade for acceptance testing of commercial ship-
ments. Option B for single-fiber weighing and Option C for the
NOTE 3—An adequate specification or other agreement between the
vibroscope may be used for acceptance testing (see Section
purchaser or supplier requires taking into account the variability between
shipping units, between packages, ends or other laboratory sampling unit
37); however, caution is advised when using Option B or
within a shipping unit if applicable, and within specimens from a single
Option C because between-laboratory precision information is
package, end or other laboratory sampling unit to provide a sampling plan
incomplete. Comparative tests as directed in 4.1.1 may be
with a meaningful producer’s risk, consumer’s risk, acceptable quality
advisable.
level, and limiting quantity level.
4.1.1 In case of dispute arising from differences in reported
5.2 Laboratory Sample—As a laboratory sample for accep-
test results when using Test Method D 1577 for acceptance
tance testing, take at random from each shipping container in
testing of commercial shipments, the purchaser and the sup-
the lot sample the number of laboratory sampling units as
plier should conduct comparative tests to determine if there is
directed in an applicable material specification or other agree-
a statistical bias between their laboratories. Competent statis-
ment between purchaser and supplier such as an agreement to
tical assistance is recommended for the investigation of bias.
use Practice D 3333 or Practice D 2258, as applicable. Prefer-
As a minimum, the two parties should take a group of samples
ably, the same number of laboratory sampling units are taken
that are as homogeneous as possible and that are from a lot of
from each shipping container in the lot sample. If differing
material of the type in question. These samples should then be
numbers of laboratory sampling units are to be taken from
randomly assigned in equal numbers to each laboratory for
shipping containers in the lot sample, determine at random
testing. The average results from the two laboratories should be
which shipping containers are to have each number of labora-
compared using the appropriate statistical analysis and a
tory units drawn.
probability level chosen by the two parties before testing is
5.2.1 For staple fiber—Take 50-g samples from laboratory
begun. If a bias is found, either the cause must be found and
sampling units.
corrected or the purchaser and the supplier must agree to
5.2.2 For sliver (or top) or tow—Take a metre (yard) from
interpret future test results with consideration to the known
the leading end which has a clean, uniform appearance.
bias.
5.2.3 For yarns—Prepare at least a 50-m (50-yd) skein from
4.2 Option A for bundle weighing is generally considered to
each package.
be the referee procedure for acceptance testing.
4.3 Option A is not recommended for measurement of linear
6. Conditioning
density of blends of production fibers having different nominal
6.1 Condition the laboratory samples as directed in Practice
linear densities.
D 1776.
4.4 The accuracy of the linear density values obtained by
Options A and B is dependent upon the accuracy with which
OPTION A—FIBER BUNDLE WEIGHING
the fibers can be cut and weighed.
7. Scope
NOTE 2—On short staple fiber, an accuracy in cutting of 1.0 % is
difficult to obtain. This problem is further complicated if crimp is present
7.1 This test method option covers the measurement of the
in the fibers.
average linear density of textile fibers by cutting and weighing.
4.4.1 The accuracy of weighing can be controlled by the
8. Summary of Test Method
number of fibers composing the bundle. However, with short
fiber of low linear density the number of fibers to be counted 8.1 Average linear density, in tex or denier units, of single
becomes prohibitive unless the bundle mass is kept low. fibers in a bundle is calculated from mass and length measure-
4.5 Options A and B are fundamental procedures which are ments on the bundle and the number of single fibers in the
used to standardize the vibroscope equipment used in Options bundle.
C1 and C2.
9. Apparatus
4.6 Test Method Options B and C are most useful for the
measurement of linear density of single fibers when further 9.1 Balance, having a capacity of 15 mg and sensitivity of
tests upon the same test specimen are required, for example, at least 0.005 mg.
D 1577
9.2 Metal Template, Die, or Mechanical Cutting Device, weighing. Refer to Test Method D 1907, Test Method D 2257,
having a precision of 61 % and designed to permit cutting or the Non-fibrous Material Section of Test Methods D 629 for
fibers of a specified length while under tension sufficient to procedures on the removal of finish.
remove crimp.
NOTE 5—Hot-water or hot solvent may cause considerable shrinkage
9.2.1 For fibers less than 50 mm in length, a template or die
and consequent changes in linear density, and should not be used.
25 mm in width for measurements in tex units (22.5 mm in
12.2 The specimens chosen from staple fiber may require
width for measurements in denier units) has been found
combing to align the fibers and remove short ends. Because
satisfactory.
fibers are easily stretched, combing must be done with extra
9.2.2 For fibers more than 50 mm in length, a mechanical
care. Comb the specimen as follows:
cutting device, for example, a cutting board having two clamps
12.2.1 Grip the specimen at one end in suitable clamp or
at a greater distance apart than the selected length and having
tweezers. Ease the specimen onto the stationary coarse comb
two central clamps for fixing specimens to the board during
needles 3 to 5 mm on the clamp side of the center of the tuft.
cutting, each with a side adjacent to the path of one of a pair of
Draw the specimen gently toward the center.
traversing blades positioned the selected length apart. Tem-
12.2.2 Lift the specimen off the comb. Replace the speci-
plates or dies of the type described in 9.2.1 can be made with
men on the needles 3 to 5 mm closer to the clamp than the last
appropriate widths for use on longer fibers.
position. Draw the specimen gently to the center as before.
9.3 Weights, for preloading crimped fibers.
12.2.3 Continue to comb the specimen as directed in 12.2.2
9.4 Forceps or Clamps, having gripping surfaces padded
until the clamp is reached and all unclamped fibers are drawn
with fiber board, cork, or rubber, and wide enough to hold a
to the center.
bundle of fibers firmly.
12.2.4 Reverse the specimen. Clamp it in the combed
9.5 Stationary Coarse Comb, approximately 63 mm in
segment approximately 3 to 5 mm from the uncombed seg-
width and having needles approximately 12.5 mm in length
ment, near the center. Comb the other end of the specimen,
and spaced 19 needles to the centimetre.
progressing from tip to center in 3 to 5 mm increments. Discard
9.6 Cathetometer.
the combings.
12.3 Arrange fibers from filament yarn or tows in parallel
10. Verification of Equipment Parameters
alignment.
10.1 Determine that the length defined by the templates or
the cutting edges of dies and mechanical cutting devices is
13. Procedure
correct within 1 % by accurate measurement of these devices
13.1 Test the specimens in the standard atmosphere for
with a cathetometer.
testing textiles, which is 21 6 1°C (70 6 2°F) and 656 2%
10.2 Determine that the balance and pretension weights are
relative humidity.
correct within 60.5 % by comparison with standard weights.
13.2 Place the bundle of fibers prepared as directed in 12.2
or 12.3 in a cutting device or on a flat cutting surface. Make
11. Test Specimens
certain the fibers are in parallel alignment.
11.1 From each laboratory sampling unit in a container, take
13.3 If crimp is present, remove it by pretensioning the
five specimens at random. If the standard deviation determined
specimen under a tension determined as directed in X1.1 of the
for the container from which the laboratory sampling units
Appendix.
were taken is more than a value agreed upon between the
purchaser and supplier, continue testing in groups of five NOTE 6—Upon visual examination, if crimp does not appear to be
completely removed even at greater pretensioning than the minimum
specimens from the same laboratory sampling units in the
determined, note this in the report.
container until the standard deviation for all specimens tested
for the container is not more than the agreed-to value or stop
13.4 Cut the specimen to the selected length using template,
with a specified number testing by agreement.
die, or cutting device.
11.2 Select tufts or bundles of fibers containing a sufficient
13.5 Weigh the specimen to the nearest 0.005 mg.
number of fibers to weigh between 0.5 and 7.5 mg when cut to
13.6 Count the number of fibers in the bundle.
the specified length. If fibers from yarns are to be tested,
NOTE 7—Counting of fine fibers is facilitated b
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