ASTM D1440-96
(Test Method)Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method)
Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method)
SCOPE
1.1 This test method covers the determination of the fiber length and length distribution in loose cotton fibers.
Note 1-For another method for measuring fiber length, see Test Method D 1447.
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.
General Information
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Standards Content (Sample)
Designation: D 1440 – 96
Standard Test Method for
Length and Length Distribution of Cotton Fibers (Array
Method)
This standard is issued under the fixed designation D 1440; 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 that length which is exceeded by 25 % of the fibers by weight
in the test specimen.
1.1 This test method covers the determination of the fiber
3.2 For definitions of other terms used in this test method,
length and length distribution in loose cotton fibers.
refer to Terminology D 123.
NOTE 1—For another method for measuring fiber length, see Test
Method D 1447.
4. Summary of Test Method
1.2 This standard does not purport to address all of the
4.1 A sorting apparatus consisting of two banks of parallel
safety concerns, if any, associated with its use. It is the
combs is used to straighten and align the fibers in a 75-mg test
responsibility of the user of this standard to establish appro-
specimen. The fibers are pulled from one bank of combs and
priate safety and health practices and determine the applica-
transferred to the other in such a manner that one end of each
bility of regulatory limitations prior to use.
fiber is aligned with the base comb. The transfer is repeated to
straighten the other ends of the fibers. As the fibers are
2. Referenced Documents
withdrawn from the combs for the third time, they are placed
2.1 ASTM Standards:
in order of length on velvet covered boards. The pulls are
D 123 Terminology Relating to Textiles
measured, and those that fall within each length interval are
D 1441 Practice for Sampling Cotton Fibers for Testing
collected and weighed. From these weight-length data, the
D 1447 Test Method for Length and Length Uniformity of
upper quartile length, mean length, and coefficient of length
Cotton Fibers by Fibrograph Measurement
variation are calculated.
D 1776 Practice for Conditioning Textiles for Testing
5. Significance and Use
3. Terminology
5.1 The array method provides objective measurements for
3.1 Definitions:
determining the fiber length and length distribution in a sample
3.1.1 coeffıcient of variation, CV, n—a measure of the
of cotton. The results can be plotted to show the length-weight
dispersion of observed values equal to the standard deviation
distribution of all the fibers in the sample. Data obtained from
for the values divided by the average of the values; may be
array tests are useful in fiber length research studies, for
expressed as a percentage of the average (CV %).
investigation of changes in fiber length distribution in ginning
3.1.2 length group, n—all fibers, or pulls, whose lengths fall
and mill processing, and for other research purposes.
within a given length interval.
5.2 Upper quartile length is correlated with, but usually
3.1.3 length interval, n—a class interval of ⁄8 in. (3 mm),
longer than, Fibrograph and 2.5 % span length as defined in
usually designated by its midpoint length in odd-numbered
Test Method D 1447. Judgment must be used in making
sixteenths of an inch.
comparisons between length measures from arrays and mea-
1 1
Example:the0to ⁄8-in. interval is designated as ⁄16.
sures obtained by other methods, which may be basically
3.1.4 mean length, n—in testing of cotton fibers, the average
different.
length of all fibers in the test specimen based on weight-length
5.3 The coefficient of length variation is a measure of length
data.
distribution, or nonuniformity of length. Because the fiber
3.1.5 pull, n—a group of fibers grasped by the forceps at
weight-length distribution is usually highly skewed, statistical
one time and drawn from the specimen in the combs.
judgments based on the assumption of normality are not
3.1.6 upper quartile length, n—in testing of cotton fibers,
justified.
5.4 The array method makes a physical separation of fibers
of different lengths. It therefore serves as a standard, or
This test method is under the jurisdiction of ASTM Committee D-13 on
Textiles, and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers. benchmark, with which other methods may be compared and
Current edition approved Nov. 10, 1996. Published March 1997. Originally
by which their precision and accuracy may be judged.
published as D 1440 – 55. Last previous edition D 1440 – 90.
5.5 Test Method D 1440 for testing length and length
Annual Book of ASTM Standards, Vol 07.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1440
a and c—Banks of combs.
b—Forceps, tips padded with hard leather, for transferring fibers from one set of combs to the other.
d—Depressor for placing fibers in combs.
f—Dissecting needle.
g—Fork for scooping up fiber groups off velvet surface.
h—Aluminum plate covered with velvet cloth.
i—Special rule for measuring length of fiber groups.
k—Smooth plate for placing fibers onto velvet surfaces.
l—Wire rack for holding fiber groups wrapped in papers.
m—Smooth pointed tweezers.
n—Lift for raising combs in place.
o—Rack for holding velvet-covered boards.
p—Velvet-covered boards on which several pulls have been arrayed.
NOTE 1—Other accessories required for length arraying, not shown above, consist of the following: small whisk broom for cleaning velvet surfaces,
one pair of tweezers with smooth round tips, forceps similar to b but having tips padded with rubber for laying groups on velvet surfaces, small papers
1 1 1
for wrapping groups of fibers (papers 2 ⁄2 by 3 in. (62 by 75 mm)) with small envelopes for them (2 ⁄2 by 4 ⁄4 in. (62 by 110 mm)), and balances having
ranges from 0 to 25 mg and 0 to 100 mg.
FIG. 1 Combs and Accessories for Arraying Fibers According to Length
distribution of cotton fibers (array method) is not commonly 7. Sampling
used for acceptance testing of commercial shipments.
7.1 Prepare the laboratory sample as directed in Test
Method D 1441. Take either two or three subsamples depend-
6. Apparatus and Materials
ing on the precision desired. Take subsamples that weigh
6.1 Double Bank Sorter, and equipment as illustrated in Fig.
approximately 80 mg each for use in preparing the test
1. The method outlined here is especially adapted to the
specimen in one of the following manners:
Suter-Webb Duplex Cotton Fiber Sorter, but the procedure
7.1.1 From a hand sliver, carefully separate a 2-in. (50-mm)
may be carried out with other similar apparatus with more or
length of the sliver for each subsample.
less obvious alterations.
7.1.2 From a mechanically blended 3-g sliver, separate 2-in.
6.2 Balance, with a capacity of at least 25 mg and a
(50-mm) subsamples.
sensitivity of 60.05 mg.
7.1.3 From a mechanically blended 10-g sliver, pull out of
6.3 Balance, with a capacity of at least 100 mg and a
the middle of the sample a subsample about 2 in. (50 mm) long,
sensitivity of 60.1 mg.
extending through its whole thickness, and wide enough to
6.4 Standard Calibration Cotton Samples, for the calibra-
weigh approximately 80 mg. Take subsamples from near the
tion of array length measurements.
beginning, midway, and near the end of the sliver.
NOTE 2—Standard calibration cotton samples are available from the
7.2 If the laboratory samples have not been in the standard
Cotton Division, Agricultural Marketing Service, U.S. Department of
atmosphere for at least 2 h before the preparation of sub-
Agriculture, 3275 Appling Rd., Memphis, TN 38133.
samples, bring the subsamples to approximate equilibrium with
6.5 Secondary Standard Cotton—Lots of cotton the length
the standard atmosphere for testing before preparing speci-
of which has been established by extensive comparisons with
mens. Exposure to moving air in the laboratory for2his
USDA standards.
sufficient.
8. Preparation of Test Specimen
The sole source of supply of the apparatus known to the committee at this time
is the Alfred Suter Co., New York, NY. If you are aware of alternative suppliers,
8.1 Prepare one specimen from each of the three sub-
please provide this information to ASTM Headquarters. Your comments will receive
samples. Gently parallelize the fibers by hand. Remove all
careful consideration at a meeting of the responsible technical committee, which
you may attend. foreign matter, but do not discard any fibers.
D 1440
8.2 Separate from each subsample, by longitudinal division, number of fibers protrude beyond the comb nearest the
a portion weighing approximately 76 mg. If the specimen operator.
weighs more than 77 mg, reduce its weight by removing a
10.4.3 Grip the ends of a few of these fibers with the forceps
small group of fibers from the side of the specimen. If the
(Fig. 1, b) and withdraw them from the combs with a smooth
specimen weighs less than 75 mg, add a small group of fibers
horizontal motion.
taken from the side of the subsample. Never remove fibers
10.4.4 Continue holding the fiber ends with the forceps.
from either the specimen or subsample by pulling from the
Place the forceps at the farther edge of the right bank of combs
ends, as this tends to remove the longest fibers. After adjusting
and draw the fibers carefully through the combs until the edge
the specimen weight to approximately 76 mg, condition the
of the forceps is just touching the near edge of the first comb.
specimen and the remaining portion of the subsample in
Release the fibers from the forceps. With the depressor, push
accordance with Section 9.
the fibers down for a short distance into the teeth of the combs.
Repeat this procedure until the transfer of all protruding fibers
9. Conditioning
is complete. The fibers should not protrude more than ⁄16 in. (2
9.1 Practice D 1776 covers the conditioning of textiles for
mm) beyond the nearer comb of the right bank.
testing. If the laboratory samples have a moisture content of
10.4.5 Drop an additional comb of the left bank and
10 % or higher, Practice D 1776 should be used to condition
continue transferring the fibers. Do not withdraw in one pull all
the samples for testing. For samples below 10 % moisture
of the fibers protruding from a comb, but take four or more
content, the conditioning procedure outlined in 9.2 and 9.3 is
separate pulls, withdrawing in each pull those fibers which
considered adequate for length testing by this test method.
protrude farthest. The width of the specimen placed in the right
9.2 If the laboratory samples have not been in the standard
comb bank should be no greater than the width of the forceps
atmosphere for at least 2 h before the preparation of the
being used.
subsample, bring the subsamples to approximate equilibrium
10.4.6 Continue the transferring procedure, dropping combs
with the standard atmosphere for testing before preparing
as necessary, until all the fibers have been transferred from the
specimens. Exposure to moving air in the laboratory for4his
left to the right set of combs.
sufficient.
10.4.7 Using the dissecting needle (Fig. 1, f ), gently un-
9.3 After the specimens have been prepared, condition them
tangle the fiber ends extending beyond the front comb. With
in the standard atmosphere for testing. Exposure to moving air
the forceps, pull out any fibers that extend more than approxi-
in the standard atmosphere for a minimum period of2his
mately ⁄16 in. (2 mm) beyond the front comb and replace them
adequate for this test method.
in the same bank of combs in the manner described in 10.4.4.
Continue until the front ends of the fibers are straight and even.
10. Procedure
10.4.8 Drop the back combs of the bank containing the
10.1 Weigh the conditioned specimen to the nearest 0.1 mg.
specimen until fibers are encountered. Pull these protruding
Do not touch the specimen with the fingers after conditioning.
fibers from the back of the combs and place them on the test
If the specimen weighs more than 75.4 mg, use the tweezers
specimen in the same manner as was done in the transfer of the
(Fig. 1, m) to remove a small group of fibers from the side of
specimen. Continue this straightening process until fibers
the specimen. If the weight is less than 74.6 mg, add a small
pulled from the back combs extend through the front comb and
group of fibers taken with tweezers from the side of the
the ends of the specimen are straight and even. This completes
subsample. Do all sorting, measuring, and weighing in the
the first transfer.
standard atmosphere for testing.
10.5 Second Transfer:
10.2 Before testing other samples, each technician shall
10.5.1 Raise the empty bank of combs to the working
have made an array on a check test cotton (Note 2), if this has
position and rotate the sorting apparatus 180° so that the
not been done during the previous month. Results of regularly
specimen is on the left.
scheduled check tests may be used for this purpose. If the
10.5.2 Repeat the procedure used in the first transfer, steps
results do not agree with the standard value for the check test
10.4.2-10.4.8 through , transferring the specimen back to the
cotton within 60.02 in. (0.51 mm) in both upper quartile and
first set of combs.
mean length and 62.0 % for the coefficient of length variation,
10.6 Array:
the technician must make some appropriate change in tech-
10.6.1 Insert top combs.
nique and repeat the check test until acceptable results are
10.6.2 Revolve the sorting apparatus 180° and drop front
obtained.
combs until the longest fibers are reached.
10.3 If two or three technicians are available, have each
10.6.3 Using the rubber-tipped forceps (Fig. 1, b), pull out a
technician sort one of the three specimens.
10.4 First Transfer: few of the longest fibers protruding from the front comb. Lay
10.4.1 Place the test specimen in the left bank of combs the pull near one end of the velvet covered board and near the
perpendicular to and approximately in the center of the combs. long edge that is farthest from the hand holding the forceps.
Using the depressor (Fig. 1, d), depress the test specimen at Continue holding with the forceps and cover the pull with the
least ⁄16 in. (2 mm) below the tips of the comb teeth, but no smooth plate (Fig. 1, k), press down gently and move forceps
lower than half the length of the teeth. The comb fork can be and plate together toward the nearer edge of the board, thus
used to raise any fibers that are depressed below this level. dragging the fibers across the velvet and straightening them.
10.4.2 Drop front combs of the left bank until a smaller Press the fibers down firmly against the velvet, release from the
D 1440
forceps, and continue the sliding movement of the plate to 11.1.1 Upper Quartile Length (25 % point)—Starting with
press down the front ends of the fibers. the longest group, add the weights until
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