ASTM D3412-95

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 3412 – 95
Standard Test Method for
Coefficient of Friction, Yarn to Yarn
This standard is issued under the fixed designation D 3412; 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 body sliding, rolling, or flowing over another body with which
it is in contact.
1.1 This test method covers the measurement of frictional
3.1.4 radian, n—the plane angle between two radii of a
properties for both continuous filament and spun-staple yarns
circle which intersects the circumference of the circle making
under boundary friction conditions.
an arc equal in length to the radius.
1.2 This test method has been used with yarns having linear
3.1.4.1 Discussion—A radian is equal to 180° divided by p
densities ranging from 1.5 to 200 tex, but may be used with
and is approximately 57.3°.
yarns outside these ranges (15 to 1800 denier).
3.1.5 stick-slip, n—a phenomenon occurring when bound-
NOTE 1—For coefficient of friction, yarn to metal, see Test Method
ary lubrication is deficient, manifested by alternative periods of
D 3108.
sticking and slipping of the surfaces in contact.
1.3 The values stated in SI units are to be regarded as the
3.1.5.1 Discussion—At the specified sliding speed, in yarn
standard. The inch-pound units given in parentheses are for
friction testing, stick-slip cycles are long enough that they can
information only.
be readily recorded. During sticking, the frictional force slowly
1.4 This standard does not purport to address all of the
rises to a peak value, at which the slipping occurs with the
safety concerns, if any, associated with its use. It is the
frictional force rapidly decreasing to a minimum value.
responsibility of the user of this standard to establish appro-
3.1.6 wrap angle, n—in yarn friction testing, the cumulative
priate safety and health practices and determine the applica-
angular contact of the test specimen against the friction-
bility of regulatory limitations prior to use.
inducing device, expressed in radians.
3.1.7 For definitions of other textile terms used in this
2. Referenced Documents
method, refer to Terminology D 123.
2.1 ASTM Standards:
4. Summary of Test Method
D 123 Terminology Relating to Textiles
D 1776 Practice for Conditioning Textiles for Testing
4.1 A length of yarn is moved at a known speed in contact
D 1907 Test Method for Yarn Number by the Skein
with itself or similar yarn at a specified wrap angle. The input
Method
and output tensions are measured and the coefficient of friction
D 2258 Practice for Sampling Yarn for Testing
calculated. Alternatively, apparatus may be used in which the
D 3108 Test Method for Coefficient of Friction, Yarn to
ratio of input to output tension is measured allowing the
Solid Material
coefficient of friction to be indicated directly.
4.2 Two optional procedures are included. Option 1 is based
3. Terminology
on the Twisted Strand Method, using a wrap angle of 15.71 rad
3.1 Definitions:
(900°). Option 2 is based on the Capstan Method, using a wrap
3.1.1 boundary friction, n—friction at low sliding speeds
angle of 3.14 radians (180°).
(0.02 m/min or less) where lubrication occurs under thin-film
NOTE 2—Editions of Test Method D 3412 prior to the 1986 revision
lubricant conditions.
incorrectly stated the wrap angle for Option 1 to be 18.85 rad. This is
3.1.2 coeffıcient of friction, n—the ratio of the tangential
incorrect, since 3 turns of the swivel pulley do not result in a wrap angle
force that is needed to maintain uniform relative motion
of 18.85 radians. This has now been corrected to 15.71 rad. This should be
between two contacting surfaces to the perpendicular force
taken into account in comparing with earlier results.
holding them in contact.
5. Significance and Use
3.1.3 friction, n—the resistance to the relative motion of one
5.1 This test method for testing yarn-to-yarn friction is
being used, but is not recommended, for acceptance testing of
This test method is under the jurisdiction of ASTM Committee D-13 on Textiles
commercial shipments since between-laboratory precision is
and is the direct responsibility of Subcommittee D 13.58 on Yarn Test Methods,
known to be poor.
General.
Current edition approved May 15, 1995. Published July 1995. Originally 5.1.1 In some cases, the purchaser and supplier may have to
published as D 3412 – 75T. Last previous edition D 3412 – 89.
test a commercial shipment of one or more specific materials
Annual Book of ASTM Standards, Vol 07.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 3412
FIG. 1 Twisted Strand Yarn-to-Yarn Friction Apparatus—Twisted-Yarn Method
by the best available method even though the method has not 6.1.1 Friction Testing Apparatus (Indirect) —Apparatus in
been recommended for acceptance testing of commercial which the input tension is measured, or controlled to a set
shipments. In case of a dispute arising from differences in value, the output tension is measured, and the coefficient of
reported test results when using Test Method D 3412 for friction is calculated within or outside the apparatus.
acceptance testing of commercial shipments, the purchaser and 6.1.1.1 Yarn Input Tension Control—A means of controlling
the supplier should conduct comparative tests to determine if the yarn input tension to the nearest 5 % is required. A
there is a statistical bias between their laboratories. Competent demand-feed apparatus tensioned with a fixed weight is suit-
statistical assistance is recommended for the investigation of able.
bias. As a minimum, the two parties should take a group of test 6.1.1.2 Yarn Input Tension Measurement—The yarn input
specimens that are as homogeneous as possible and that are tension is measured to within 65.0 mN (60.5 gf), using a
from a lot of material of the type in question. The test suitable tension gage producing an electrical signal. The signal
specimens should then be randomly assigned in equal numbers is recorded as millinewtons (grams-force) or is used in com-
to each laboratory for testing. The average results from the two bination with the yarn output tension measured to calculate the
laboratories should be compared using Student’s t-test for coefficient of friction. If a demand-feed apparatus tensioned
unpaired data and an acceptable probability level chosen by the with a precise, known fixed mass is used, the yarn input tension
two parties before the testing is begun. If a bias is found, either need not be constantly measured and recorded.
its cause must be found and corrected or the purchaser and the 6.1.1.3 Yarn Output Tension Measurement—Yarn output
supplier must agree to interpret future test results with consid- tension is measured to within 65.0 mN (60.5 gf), using a
eration to the known bias. suitable tension gage producing an electrical signal. The signal
is recorded as millinewtons, (grams-force), or is used in
5.2 This test method is intended for the determination of
combination with the yarn input tension setting or measure-
yarn-to-yarn boundary friction coefficients measured over a
ment to calculate the coefficient of friction.
specified length of yarn.
6.1.2 Friction Testing Apparatus (Direct) —Apparatus in
5.3 The test method is useful for quality control, research,
which the ratio of output to input tensions are compared
and the characterization of yarn boundary lubricants.
directly and the coefficient of friction is indicated on a scale.
6.1.3 Auxilliary Equipment (Indirect and Direct):
NOTE 3—Because the geometry of the yarns is different, Options 1 and
6.1.3.1 Guide Pulley Arrangement—The upper and lower
2 should not be expected to give the same numerical values on the same
yarns. pulleys shalls be of the same diameter. The recommended
pulley diameter is 38 mm (1.5 in.). The separation distance
6. Apparatus
between the upper pulleys, 2 H, shall be 140 6 2 mm (5.5 6
0.1 in.). The separation distance between the axis of the lower
6.1 Option 1 (Twisted Strand Method)—A schematic dia-
pulley and a line connecting the upper pulley axes, V, shall be
gram of the elements required for twisted strand friction
measurement is shown in Fig. 1. The yarn is run over upper
pulleys and under a lower pulley and is intertwisted between
Equipment meeting these requirements may be obtained commercially from:
these pulleys. One end of the yarn (output) is taken up at a Custom Scientific Instruments Inc, 13 Wing Drive, Cedar Knolls, NJ 07292, and
Rothschild-Messinstruments, Traubstr 3, 8002 Zurich, Switzerland, represented in
controlled rate. The other end of yarn (input) is maintained at
the U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388, Spartanburg, SC 29304.
a controlled tension. The number of intertwisting wraps, the 4
Equipment meeting these requirements may be obtained commercially from:
apex angle between the input and output yarns, and the input Rothschild-Messinstruments, Traubstr 3, 8002 Zurich, Switzerland, represented in
the U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388, Spartanburg, SC 29304,
and output tensions are precisely known or recorded. From
and Shirley Developments Ltd, PO Box 6, Didsbury, Manchester M20 8SA,
these data the coefficient of yarn-on-yarn friction is calculated.
England, represented in the U.S. by Lawson Hemphill Sales Inc, PO Drawer 6388,
The required elements are: Spartanburg, SC 29304.
D 3412
between shipping units, between packages or ends within a shipping unit,
280 6 2mm(11 6 0.1 in.). All pulleys shall be in the same
and between specimens from a single package so as to provide a sampling
plane. The lower pulley may optionally be mounted so that it
plan with a meaningful producer’s risk, consumer’s risk, acceptable
can be swiveled around an axis at right angles to its axis of
quality level, and limiting quality level.
rotation and then fixed in position in the same plane as the
7.2 Laboratory Sample—As a laboratory sample for accep-
upper pulleys.
tance testing, take at random from each shipping unit in the lot
6.1.3.2 Drive Unit—The yarn takeup shall run between 20
sample the number of packages or ends directed in an
and 100 mm/min (0.75 and 4.0 in./min).
applicable material specification or other agreement between
6.2 Option 2 (Capstan Method)—A schematic diagram of
the purchaser and the supplier such as an agreement to use
the elements required for the Capstan Method is shown in Fig.
Practice D 2258. Preferably, the same number of packages
2. Suitable elements are:
should be taken from each shipping unit in the lot sample. If
6.2.1 Cylinder—A rotating mandrel of 50 6 2 mm (2.0 6
differing numbers of packages are to be taken from shipping
0.1 in.) outside diameter.
units in the lot sample, determine at random which shipping
6.2.2 Drive Unit—A mechanism designed to rotate the
units are to have each number of packages drawn.
cylinder at a surface speed of 20 6 1 mm/min (0.75 6 0.04
7.3 Test Specimens—Test one specimen from each package
in./mm).
in the laboratory sample.
6.2.3 Winding Unit—A device to wrap the yarn on the
surface of the cylinder. A helix angle of 0.2 to 0.3 rad (10 to
8. Conditioning
15°) is needed to prevent burrowing by the hanging strand of
8.1 Preparation of Test Packages—Remove sufficient yarn
yarn.
from the test packages to avoid testing non-representative
6.2.4 Tension Gage—A suitable tension gage, producing an
layers. If in doubt, remove about 10 % of the length of yarn on
electrical signal, to measure the yarn output tension which is
the package.
recorded as millinewtons or after calculation as coefficient of
8.2 The strand to be tested must have a uniform moisture
friction.
content along its length. Atmospheric conditions must there-
6.2.5 Weights—A set of weights or other device to preset the
fore be stable and the strand must be in equilibrium with the
input tension.
prevailing atmosphere. To satisfy this condition, testing should
NOTE 4—Measured stick-slip differentials are greatly dependent on
be carried out after thorough conditioning in the standard
tension transducer spring constants, yarn modulus, and recorder frequency
atmosphere for testing textiles.
responses. If interlaboratory checks are required, the same type of tension
8.3 Preconditioning—Precondition packages of yarn for at
transducer and recorder should be used and the distance between the
least3hinan atmosphere with a relative humidity between 5
transducer and the hanging weight to center line of the mandrel must be
specified.
and 25 % and a temperature not exceeding 50°C (121°F).
8.4 Conditioning—Condition the preconditioned packages
7. Sampling
of yarn in the standard atmosphere for testing textiles (relative
7.1 Lot Sample—As a lot sample for acceptance testing,
humidity 65 6 2 % and temperature 21 6 1°C (70 6 2°F)) in
take at random the number of shipping containers directed in
moving air until it has reached moisture equilibrium for testing,
an applicable material specification or other agreement be-
as directed in Practice D 1776.
tween the purchaser and the supplier, such as an agreement to
9. Procedure
use Practice D 2258. Consider shipping containers to be the
primary sampling units.
9.1 Test all specimens in the standard atmosphere for testing
textiles, which is a relative humidity 65 6 2 % and temperature
NOTE 5—An adequate specification or other agreement between the
216 1°C (70 6 2°F).
purchaser and the supplier requires taking into account the variability
9.2 Option 1 (Twisted Strand Method):
9.2.1 Calibrate the apparatus to the specified full scale
reading. Check the freedom of the pulleys by running yarn
through the apparatus to determine the difference between
input and output tensions with no yarn friction. Designate this
value as DT.
9.2.2 Feed the yarn through the apparatus. If the test
apparatus is equipped with a rotating lower pulley, rotate the
swivel pulley clockwise through three complete revolutions.
Otherwise, remove the yarn from the lower pulley by placing
it around fingers, rotate the hand to twist the yarn loop three
complete revolutions, and then replace the yarn under the
lower pulley. The first half revolution brings the input and
output sections of the yarn into contact and corresponds to a
wrap angle of zero. The additional two and one-half revolu-
tions produces a wrap angle of 15.7 rad (900°).
9.2.3 Measure the length W of the intertwisted portion of
FIG. 2 Yarn-to-Yarn Friction Apparatus—Capstan Method yarn. Measure the distance between the upper pulley axes 2H
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