ASTM D1440-07(2012)
(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)
SIGNIFICANCE AND USE
The array method provides objective measurements for determining the fiber length and length distribution in a sample of cotton. The results can be plotted to show the length-weight distribution of all the fibers in the sample. Data obtained from array tests are useful in fiber length research studies, for investigation of changes in fiber length distribution in ginning and mill processing, and for other research purposes.
Upper quartile length is correlated with, but usually longer than, Fibrograph and 2.5 % span length as defined in Test Method D1447. Judgment must be used in making comparisons between length measures from arrays and measures obtained by other methods, which may be basically different.
The coefficient of length variation is a measure of length distribution, or nonuniformity of length. Because the fiber weight-length distribution is usually highly skewed, statistical judgments based on the assumption of normality are not justified.
The array method makes a physical separation of fibers of different lengths. It therefore serves as a standard, or benchmark, with which other methods may be compared and by which their precision and accuracy may be judged.
Test Method D1440 for testing length and length distribution of cotton fibers (array method) is not commonly used for acceptance testing of commercial shipments.
a and cBanks of combs.
bForceps, tips padded with hard leather, for transferring fibers from one set of combs to the other.
dDepressor for placing fibers in combs.
fDissecting needle.
gFork for scooping up fiber groups off velvet surface.
hAluminum plate covered with velvet cloth.
iSpecial rule for measuring length of fiber groups.
kSmooth plate for placing fibers onto velvet surfaces.
lWire rack for holding fiber groups wrapped in papers.
mSmooth pointed tweezers.
nLift for raising combs in place.
oRack for holding velvet-covered boards.
pVelvet-covered boards on which several pulls have been arrayed.
...
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 D1447.
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.
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Designation: D1440 − 07 (Reapproved 2012)
Standard Test Method for
Length and Length Distribution of Cotton Fibers (Array
Method)
This standard is issued under the fixed designation D1440; 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 transferred to the other in such a manner that one end of each
fiber is aligned with the base comb. The transfer is repeated to
1.1 This test method covers the determination of the fiber
straighten the other ends of the fibers. As the fibers are
length and length distribution in loose cotton fibers.
withdrawn from the combs for the third time, they are placed
NOTE 1—For another method for measuring fiber length, see Test
in order of length on velvet covered boards. The pulls are
Method D1447.
measured, and those that fall within each length interval are
1.2 This standard does not purport to address all of the
collected and weighed. From these weight-length data, the
safety concerns, if any, associated with its use. It is the
upper quartile length, mean length, and coefficient of length
responsibility of the user of this standard to establish appro-
variation are calculated.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
5. Significance and Use
2. Referenced Documents 5.1 The array method provides objective measurements for
determining the fiber length and length distribution in a sample
2.1 ASTM Standards:
of cotton. The results can be plotted to show the length-weight
D123 Terminology Relating to Textiles
distribution of all the fibers in the sample. Data obtained from
D1441 Practice for Sampling Cotton Fibers for Testing
array tests are useful in fiber length research studies, for
D1447 Test Method for Length and Length Uniformity of
investigation of changes in fiber length distribution in ginning
Cotton Fibers by Photoelectric Measurement
and mill processing, and for other research purposes.
D1776 Practice for Conditioning and Testing Textiles
D7139 Terminology for Cotton Fibers
5.2 Upper quartile length is correlated with, but usually
longer than, Fibrograph and 2.5 % span length as defined in
3. Terminology
Test Method D1447. Judgment must be used in making
3.1 ForallterminologyrelatedtoD13.11,CottonFibers,see
comparisons between length measures from arrays and mea-
Terminology D7139.
sures obtained by other methods, which may be basically
3.1.1 The following terms are relevant to this standard:
different.
coefficient of variation, length group, length interval, mean
5.3 The coefficient of length variation is a measure of length
length, pull, upper quartile length.
distribution, or nonuniformity of length. Because the fiber
3.2 For all other terminology related to textiles see Termi-
weight-length distribution is usually highly skewed, statistical
nology D123.
judgments based on the assumption of normality are not
justified.
4. Summary of Test Method
5.4 The array method makes a physical separation of fibers
4.1 A sorting apparatus consisting of two banks of parallel
of different lengths. It therefore serves as a standard, or
combs is used to straighten and align the fibers in a 75-mg test
benchmark, with which other methods may be compared and
specimen. The fibers are pulled from one bank of combs and
by which their precision and accuracy may be judged.
5.5 Test Method D1440 for testing length and length distri-
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers. bution of cotton fibers (array method) is not commonly used
Current edition approved July 1, 2012. Published August 2012. Originally
for acceptance testing of commercial shipments.
approved in 1955. Last previous edition approved in 2007 as D1440 – 07. DOI:
10.1520/D1440-07R12.
6. Apparatus and Materials
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Double Bank Sorter, and equipment as illustrated in Fig.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 1. The method outlined here is especially adapted to the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1440 − 07 (2012)
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
Suter-Webb Duplex Cotton Fiber Sorter, but the procedure precision desired. Take subsamples that weigh approximately
may be carried out with other similar apparatus with more or 80 mg each for use in preparing the test specimen in one of the
less obvious alterations. following manners:
7.1.1 From a hand sliver, carefully separate a 2-in. (50-mm)
6.2 Balance, with a capacity of at least 25 mg and a
length of the sliver for each subsample.
sensitivity of 60.05 mg.
7.1.2 From a mechanically blended 3-g sliver, separate 2-in.
6.3 Balance, with a capacity of at least 100 mg and a
(50-mm) subsamples.
sensitivity of 60.1 mg.
7.1.3 From a mechanically blended 10-g sliver, pull out of
themiddleofthesampleasubsampleabout2in.(50mm)long,
6.4 Standard Calibration Cotton Samples, for the calibra-
tion of array length measurements. extending through its whole thickness, and wide enough to
weigh approximately 80 mg. Take subsamples from near the
NOTE 2—Standard calibration cotton samples are available from the
beginning, midway, and near the end of the sliver.
Cotton Division, Agricultural Marketing Service, U.S. Department of
Agriculture, 3275 Appling Rd., Memphis, TN 38133.
7.2 If the laboratory samples have not been in the standard
6.5 Secondary Standard Cotton—Lots of cotton the length atmosphere for at least 2 h before the preparation of
subsamples, bring the subsamples to approximate equilibrium
of which has been established by extensive comparisons with
with the standard atmosphere for testing before preparing
USDA standards.
specimens. Exposure to moving air in the laboratory for2his
7. Sampling
sufficient.
7.1 Prepare the laboratory sample as directed in Practice
8. Preparation of Test Specimen
D1441. Take either two or three subsamples depending on the
8.1 Prepare one specimen from each of the three sub-
samples. Gently parallelize the fibers by hand. Remove all
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, foreign matter, but do not discard any fibers.
pleaseprovidethisinformationtoASTMHeadquarters.Yourcommentswillreceive
8.2 Separate from each subsample, by longitudinal division,
careful consideration at a meeting of the responsible technical committee, which
you may attend. a portion weighing approximately 76 mg. If the specimen
D1440 − 07 (2012)
weighs more than 77 mg, reduce its weight by removing a 10.4.2 Drop front combs of the left bank until a smaller
small group of fibers from the side of the specimen. If the number of fibers protrude beyond the comb nearest the
specimen weighs less than 75 mg, add a small group of fibers operator.
taken from the side of the subsample. Never remove fibers 10.4.3 Griptheendsofafewofthesefiberswiththeforceps
from either the specimen or subsample by pulling from the (Fig. 1, b) and withdraw them from the combs with a smooth
ends, as this tends to remove the longest fibers.After adjusting horizontal motion.
the specimen weight to approximately 76 mg, condition the 10.4.4 Continue holding the fiber ends with the forceps.
specimen and the remaining portion of the subsample in Place the forceps at the farther edge of the right bank of combs
accordance with Section 9. and draw the fibers carefully through the combs until the edge
of the forceps is just touching the near edge of the first comb.
Release the fibers from the forceps. With the depressor, push
9. Conditioning
the fibers down for a short distance into the teeth of the combs.
9.1 Practice D1776 covers the conditioning of textiles for
Repeat this procedure until the transfer of all protruding fibers
testing. If the laboratory samples have a moisture content of
is complete.The fibers should not protrude more than ⁄16 in. (2
10 % or higher, Practice D1776 should be used to condition the
mm) beyond the nearer comb of the right bank.
samples for testing. For samples below 10 % moisture content,
10.4.5 Drop an additional comb of the left bank and
the conditioning procedure outlined in 9.2 and 9.3 is consid-
continuetransferringthefibers.Donotwithdrawinonepullall
ered adequate for length testing by this test method.
of the fibers protruding from a comb, but take four or more
9.2 If the laboratory samples have not been in the standard
separate pulls, withdrawing in each pull those fibers which
atmosphere for at least 2 h before the preparation of the
protrude farthest.The width of the specimen placed in the right
subsample, bring the subsamples to approximate equilibrium
comb bank should be no greater than the width of the forceps
with the standard atmosphere for testing before preparing
being used.
specimens. Exposure to moving air in the laboratory for4his
10.4.6 Continue the transferring procedure, dropping combs
sufficient.
as necessary, until all the fibers have been transferred from the
left to the right set of combs.
9.3 After the specimens have been prepared, condition them
10.4.7 Using the dissecting needle (Fig. 1, f ), gently un-
in the standard atmosphere for testing. Exposure to moving air
tangle the fiber ends extending beyond the front comb. With
in the standard atmosphere for a minimum period of2his
the forceps, pull out any fibers that extend more than approxi-
adequate for this test method.
mately ⁄16 in. (2 mm) beyond the front comb and replace them
in the same bank of combs in the manner described in 10.4.4.
10. Procedure
Continue until the front ends of the fibers are straight and even.
10.1 Weigh the conditioned specimen to the nearest 0.1 mg.
10.4.8 Drop the back combs of the bank containing the
Do not touch the specimen with the fingers after conditioning.
specimen until fibers are encountered. Pull these protruding
If the specimen weighs more than 75.4 mg, use the tweezers
fibers from the back of the combs and place them on the test
(Fig. 1, m) to remove a small group of fibers from the side of
specimen in the same manner as was done in the transfer of the
the specimen. If the weight is less than 74.6 mg, add a small
specimen. Continue this straightening process until fibers
group of fibers taken with tweezers from the side of the
pulled from the back combs extend through the front comb and
subsample. Do all sorting, measuring, and weighing in the
the ends of the specimen are straight and even. This completes
standard atmosphere for testing.
the first transfer.
10.2 Before testing other samples, each technician shall
10.5 Second Transfer:
have made an array on a check test cotton (Note 2), if this has
10.5.1 Raise the empty bank of combs to the working
not been done during the previous month. Results of regularly
position and rotate the sorting apparatus 180° so that the
scheduled check tests may be used for this purpose. If the
specimen is on the left.
results do not agree with the standard value for the check test
10.5.2 Repeat the procedure used in the first transfer, steps
cotton within 60.02 in. (0.51 mm) in both upper quartile and
10.4.2 – 10.4.8, transferring the specimen back to the first set
mean length and 62.0 % for the coefficient of length variation,
of combs.
the technician must make some appropriate change in tech-
10.6 Array:
nique and repeat the check test until acceptable results are
10.6.1 Insert top combs.
obtained.
10.6.2 Revolve the sorting apparatus 180° and drop front
10.3 If two or three technicians are available, have each
combs until the longest fibers are reached.
technician sort one of the three specimens.
10.6.3 Using the rubber-tipped forceps (Fig. 1, b), pull out a
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.
D1440 − 07 (2012)
Pressthefibersdownfirmlyagainstthevelvet,releasefromthe 11.1.1 Upper Quartile Length (25 % point)—Starting with
forceps, and continue the sliding movement of the plate to the longest group, add the weights until a sum is obtained that
press down the front ends of the fibers. is equal to, or greater than, one fourth of the total weight of the
10.6.4 Continue the process of withdrawal and placement of array and note the lower limit of the array length group at or in
fibers on the velvet boards, placing each successive pull
...
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