Overlength Fiber Content of Manufactured Staple Fiber: Standard Test Method For
Overlength Fiber Content of Manufactured Staple Fiber: Standard Test Method For
Overlength Fiber Content of Manufactured Staple Fiber: Standard Test Method For
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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tests that are as homogeneous as possible, drawn from the same
lot of material as the samples that resulted in disparate results
during initial testing and randomly assigned in equal numbers
to each laboratory. The test results from the laboratories
involved should be compared using a statistical test for
unpaired data, a probability level chosen prior to the testing
series. If a bias is found, either its cause must be found and
corrected, or future test results for that material must be
adjusted in consideration of the known bias.
6. Apparatus
6.1 Fibrosampler,3Model 335A of 335B (Fig. 1), equipped
with the following:
6.1.1 Combs,3Model 336 (Fig. 2).
6.1.2 Spacing Gage.
6.1.3 Specimen Board, board covered with short pile or
FIG. 1 Fibrosampler plush surface on one side, for displaying the test specimen.
6.1.4 Brush, for brushing the test specimen.
6.1.5 Tweezers, for removing the long fibers from the
specimen board for verification.
NOTE 2—Fibrosampler Model 192, which is used for sampling cotton,
(Method D1447) has been used successfully with this method, but the
above listed models and combs yield better results because long fibers are
less likely to be pulled from the combs during beard preparation.
6.2 Laboratory Carding Machine or Opener/Blender Model
3383 is needed for use with Fibrosampler Model 335A.
6.3 Analytical Balance, capable of weighing the specimen
to within 0.01 % of its mass.
6.4 Scale, graduated to the nearest 1 mm (1⁄16-in.).
7. Sampling
7.1 Lot Sampling—As a lot sample for acceptance testing,
FIG. 2 Fibrosampler Combs
take at random the number of shipping containers directed in
the applicable material specification or other agreement be-
tween the purchaser and supplier, such as an agreement to use
cutter, their existence within the fiber population is not uniform
Practice D3333 or Practice D2258. Consider shipping contain-
and their occurrence in the population follows a highly skewed
ers to be the primary sampling units.
distribution.
NOTE 3—An adequate specification or other agreement between the
5.3 Manual methods of determining overlength fiber require
purchaser or supplier requires taking into account the variability between
much more operator time, and the standard deviations of the shipping units, between packages, ends or other laboratory sampling unit
test between laboratories and operators are high. Use of the within a shipping unit if applicable, and within specimens from a single
Fibrosampler method greatly reduces both operator time and package, end or other laboratory sampling unit to provide a sampling plan
standard deviation of testing. with a meaningful producer’s risk, consumer’s risk, acceptable quality
level, and limiting quantity level.
5.4 In manufacturing it is important to know if fibers are
7.2 Laboratory Sample—As a laboratory sample for accep-
overlength due to looping of the tow or multiple length due to
tance testing, take at random from each shipping container in
damaged cutters.
the lot sample the number of laboratory sampling units as
5.5 This method for testing staple fiber for overlength fiber directed in an applicable material specification or other agree-
is not recommended for acceptance testing (see 13.1). ment between purchaser and supplier such as an agreement to
5.5.1 In some cases the purchaser and the supplier may have use Practice D3333 or Practice D2258. Preferably, the same
to test a commercial shipment of one or more specific materials number of laboratory sampling units are taken from each
by the best available method, even though the method has not
been recommended for acceptance testing of commercial
shipments. If there are differences of practical significance 3
The sole source of supply of the apparatus known to the committee at this time
between reported test results for two laboratories (or more), is Special Instruments Laboratory, Inc., 312 W. Vine Ave., P.O. Box 1950,
Knoxville, TN. 37901. If you are aware of alternative suppliers, please provide this
comparative test should be performed to determine if there is a
information to ASTM International Headquarters. Your comments will receive
statistical bias between them, using competent statistical assis- careful consideration at a meeting of the responsible technical committee,1 which
tance. As a minimum, use the samples for such a comparative you may attend.
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D3513 − 02 (2012)
shipping container in the lot sample. If differing numbers of of the sample plate. Then relax the hand pressure against the
laboratory sampling units are to be taken from shipping plate to prevent fiber damage or breakage.
containers in the lot sample, determine at random which 8.5.4 With the right hand, turn the pivot arm one complete
shipping containers are to have each number of laboratory units counterclockwise revolution. This carries the comb teeth
drawn. across the face of the protruding test sample and allows a
7.2.1 Take 100-g samples of staple fiber, sliver or top for segment of the fiber beard to form on the comb. See Note 4.
each laboratory sampling unit. 8.5.5 Ease the test specimen from the plate. Rotate the test
7.3 Test Specimens—From each laboratory sampling unit, specimen to present a new surface and move it up the sample
take one specimen. If the standard deviation determined for the plate.
laboratory sample is more than a value agreed upon between 8.5.6 Continue as directed in 8.5.3 through 8.5.4 until the
the purchaser and supplier, continue testing one specimen from comb is uniformly loaded with a milligram mass of 160 to 190
each unit in the laboratory sample until the standard deviation times the nominal staple length.
for all specimens tested is not more than the agreed to value or, NOTE 5—The comb can usually be loaded in three to five turns around
by agreement, stop testing after a specified number. the cylinder.
8. Preparation of Test Specimens 8.5.7 Withdraw the comb from its holder.
8.1 Clean the card clothing on the Fibrosampler before or 9. Preparation and Adjustment of Apparatus
after the preparation of each beard to maintain effective 9.1 Set up and adjust the Fibrosampler as directed in the
combing action. To do this, raise the release button (F, Fig. 1) manufacturer’s instruction manual.
to allow the doffer roller to fall into the cleaning position. 9.1.1 Check the clearance between comb and sampling
Rotate the pivot arm clockwise while holding the doffer against holes in the sampler drum, using the supplied gage. Adjust as
the card clothing. At the bottom of the pivot arm a cleaner necessary.
comb may be rotated into the doffer clothing by the left hand 9.1.2 Test the Fibrosampler comb clamp mechanism for
while the doffer roll is rotated clockwise by the right hand. fiber beard holding capability. This may be accomplished by
8.2 Remove a 25 6 5-g test specimen from each laboratory withdrawing the dog (c, Fig. 2) to open the clamp manually,
sample. placing a small tuft of fiber under the teeth of the comb, closing
8.3 Prepare a fiber beard specimen from each test specimen the clamp mechanism by forcing the dog into the comb, and
as directed in 8.4 using Fibrosampler Model 335A, or in 8.5 then pulling the fibers. The clamp holding capacity should be
using Fibrosampler Model 335B. high enough to allow the comb to be picked up by a tuft of 50
to 100 fibers.
8.4 Fibrosampler Model 335A:
8.4.1 Process the test specimen through a laboratory blender 10. Procedure
such as a laboratory carding machine, or a Model 338
10.1 Place the comb, with the fiber beard firmly clamped, on
Opener/Blender.
the specimen board. Brush the beard to lay flat against the
8.4.2 Place an empty comb in the comb holder.
board surface. The density of the beard will be observed to
8.4.3 With the left hand, place the test specimen in the
taper and end at a line representing the nominal cut length of
cylinder and press it against the curved perforated sample
the staple.
plate.
8.4.4 With a 10 to 20-mm diameter circular motion of the 10.2 Measure the distance (to the nearest 1 mm) from the
left hand work the fibers until they protrude through the holes base of the comb to the line, representing the nominal cut
of the sample plate. Then relax the hand pressure against the staple, observed in 10.1. Overlength fibers will be observed to
plate to prevent fiber damage or breakage. extend beyond this well-defined line.
8.4.5 With the right hand, turn the pivot arm one complete 10.3 Establish a line, located to the nearest 1 mm and
counterclockwise revolution. This carries the comb teeth parallel to the face of the comb, that is 1.1 times the distance
across the face of the protruding test sample and allows a fiber measured in 10.2.
beard to be drawn from the test specimen.
10.4 Unclamp the fibers by withdrawing the dog (E, Fig. 2).
NOTE 4—Excessive hand pressure on the test specimen during this step With tweezers, remove those fibers that extend beyond the line
will require excessive force to turn the pivot arm and will not allow the established in 10.3. Determine, by measurement to the nearest
fibers to be drawn onto the comb properly and cause excessive fiber
damage during comb loading.
1 mm (1/16 in.), whether the fibers are actually overlength, or
multiple length, or extending across the line because fiber ends
8.4.6 Withdraw the comb from its holder. are entangled in a nep, or tied.
8.5 Fibrosampler 335B: NOTE 6—Overlength fibers by definition include multiple-length fibers.
8.5.1 Place an empty comb in the comb holder. When determining the cause of overlength fibers, however, it is advisable
8.5.2 With the left hand, place the test specimen in the to exclude multiple-length fibers from the overlength count. It may also be
cylinder and press a small segment of the specimen across and advisable to count the number, but not measure the length, of neps or tied
against the lower area of the perforated sample plate. fibers since they are indicative of other processing problems.
8.5.3 With a 10 to 20-mm diameter circular motion of the 10.4.1 Measure the fiber lengths as directed in Test Method
left hand, work the fibers until they protrude through the holes D1447.
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D3513 − 02 (2012)
10.5 Count the number of overlength fibers verified in 10.4. 12. Report
10.6 Count the number of multiple length fibers verified in 12.1 State that the specimens were tested as directed in Test
10.4. Method D3513. Describe the material or product sampled and
10.7 Remove the fiber beard from the comb and weigh the the method of sampling used.
specimen to the nearest 0.01 % of its mass. Include the weight 12.2 Report the following information:
of fibers removed from the beard if there is a sufficient number 12.2.1 Report the type Fibrosampler used in the test and, in
to affect the fiber beard weight. the case of the Model 335A, the method of sample opening and
blending,
11. Calculation 12.2.2 Percent overlength fiber for each specimen,
11.1 Using the stated value of the linear density and the 12.2.3 Percent multiple length for each specimen,
nominal cut length, calculate the number of fibers in the fiber 12.2.4 The average overlength measurement for each
beard, using specimen, if calculated,
N 5 104 M/ ~ L 3 T ! (1)
12.2.5 The average multiple length measurement for each
specimen, if calculated, and
where: 12.2.6 The individual overlength and multiple length
N = number of fibers in the fiber beard, measurements, if requested.
M = mass of the test specimen, mg,
T = fiber linear density, decitex, and 13. Precision and Bias
L = nominal fiber length, mm. 13.1 Precision—The distribution of overlength fibers in
NOTE 7—To convert denier to decitex divide denier by 0.9. commercial production is highly skewed, rendering such
11.2 Calculate the percent overlength fiber, using Eq 2: samples unsatisfactory for interlaboratory tests. Consequently,
Overlength, fiber, % 5 100 n/N (2) two series of samples were prepared in which seven known
levels of multiple-length fiber were added in amounts ranging
where: from zero to 4.0 %. A 3.3-dtex, 80-mm (31/8-in.) rayon was
n = number of overlength fibers in the fiber beard as added to a 3.3-dtex, 40-mm (19/16-in.) rayon and blended on
determined in 10.5 and a cotton carding machine. A 3.3-dtex, 100-mm (4-in.) polyester
N = number of fibers in the fiber beard as calculated in 11.1. was added to a 3.3-dtex, 50-mm (2-in.) polyester and blended
11.3 Calculate the percent multiple length fiber, using Eq 3: on a Spinlab Model 338 Opener/Blender.
13.1.1 Within a laboratory the correlation between the
Multiple 2 length fiber, % 5 100 p/N (3) known amount of overlength contaminant in a prepared speci-
where: men and the overlength count by this procedure was good. This
p = number of multiple length fiber as determined in 10.6 relationship does not hold with between-laboratory tests.
and Therefore, new laboratory tests will be undertaken by this
N = number of fibers in the fiber beard as calculated in 11.1. method.
NOTE 8—The Fibrosampler produces a length-biased beard.4 For 13.2 Bias—No justifiable statement on the bias of this test
example, the probability of a double-length fiber appearing in the test method can be made using normally manufactured cut staple.
beard is twice as great as that of a unity length fiber.
The occurrence of overlength fiber is an incident of seldom
11.4 If requested, calculate the average of the measurements occurrence and is therefore nonuniformly distributed in the
made in 10.4 for the overlength fibers and for the multiple manufactured product.
length fibers for each specimen.
14. Keywords
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“A Method of Fiber-Length Analysis Using the Fibrograph” by Dr. K. L. 14.1 length; multiple—length staple fibers; overlength
Hertel, Textile Research, Vol X, No. 12, October 1940. staple fibers ; staple fibers
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