ASTM G143-03(2009)
(Test Method)Standard Test Method for Measurement of Web/Roller Friction Characteristics
Standard Test Method for Measurement of Web/Roller Friction Characteristics
SIGNIFICANCE AND USE
This test method is intended to simulate the slip of a flexible web on a roller in a machine or tribosystem that conveys web materials. Flexible webs such as plastic sheeting, paper, elastomers, metal foils, and cloth are often transported in manufacturing processes by combinations of driving and idler rollers. The friction characteristics of the web/roller interface often affects the web transport process. If the web/roller friction is too low, the web can slip on the rollers and be damaged or damage the roller. High friction on the other hand, can lead to steering problems and overloading of driving motors.
This test method can be used to rank rollers for their ability to resist slip versus a particular web material (high friction). Conversely this test method can assess web materials or web surface coatings such as waxes and lubricants. In this latter case, the goal may be a low-friction product made from a web (film, magnetic media, paper, and so forth).
If a tribosystem involves transport of a flexible web on a roller, this is an appropriate test to use to measure the friction characteristics of the roller/web couple.
SCOPE
1.1 This test method covers the simulation of a roller/web transport tribosystem and the measurement of the static and kinetic coefficient of friction of the web/roller couple when sliding occurs between the two. The objective of this test method is to provide users with web/roller friction information that can be used for process control, design calculations, and for any other function where web/roller friction needs to be known.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G143 − 03(Reapproved 2009)
Standard Test Method for
Measurement of Web/Roller Friction Characteristics
This standard is issued under the fixed designation G143; 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 G115 Guide for Measuring and Reporting Friction Coeffi-
cients
1.1 This test method covers the simulation of a roller/web
G117 Guide for Calculating and Reporting Measures of
transport tribosystem and the measurement of the static and
Precision Using Data from Interlaboratory Wear or Ero-
kinetic coefficient of friction of the web/roller couple when
sion Tests
sliding occurs between the two. The objective of this test
G163 Guide for Digital Data Acquisition in Wear and
method is to provide users with web/roller friction information
Friction Measurements
that can be used for process control, design calculations, and
for any other function where web/roller friction needs to be
3. Terminology
known.
3.1 Definitions of Terms Specific to This Standard:
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 3.1.1 blocking, n—unintentional adhesion between plastic
standard.
films or between a film and another surface. D883
1.3 This standard does not purport to address all of the
3.1.2 coeffıcient of friction, µ, n—in tribology—the dimen-
safety concerns, if any, associated with its use. It is the
sionlessratioofthefrictionforce(F)betweentwobodiestothe
responsibility of the user of this standard to establish appro-
normal force (N) pressing these bodies together. G40
priate safety and health practices and determine the applica-
3.1.3 friction force, n—the resisting force tangential to the
bility of regulatory limitations prior to use.
interface between two bodies when, under the action of
external force, one body moves or tends to move relative to the
2. Referenced Documents
other. G40
2.1 ASTM Standards:
3.1.4 kinetic coeffıcient of friction, n— the coefficient of
D883 Terminology Relating to Plastics
D1894 Test Method for Static and Kinetic Coefficients of friction under conditions of macroscopic relative motion be-
tween two bodies. G40
Friction of Plastic Film and Sheeting
D3108 Test Method for Coefficient of Friction,Yarn to Solid
3.1.5 stick-slip, n—a cyclic fluctuation in the magnitudes of
Material
friction force and relative velocity between two elements in
E8 Test Methods for Tension Testing of Metallic Materials
sliding contact, usually associated with a relaxation oscillation
E122 Practice for Calculating Sample Size to Estimate,With
dependent on elasticity in the tribosystem and on a decrease of
Specified Precision, the Average for a Characteristic of a
the coefficient of friction with onset of sliding or with increase
Lot or Process
of sliding velocity. G40
E177 Practice for Use of the Terms Precision and Bias in
3.1.5.1 Discussion—Classical or true stick-slip, in which
ASTM Test Methods
each cycle consists of a stage of actual stick followed by a
E691 Practice for Conducting an Interlaboratory Study to
stage of overshoot slip, requires that the kinetic coefficient is
Determine the Precision of a Test Method
lower than the static coefficient.Amodified form of relaxation
G40 Terminology Relating to Wear and Erosion
oscillation, with near-harmonic fluctuation in motion, can
occur when the kinetic coefficient of friction decreases gradu-
1 ally with increasing velocity within a certain velocity range.A
This test method is under the jurisdiction of ASTM Committee G02 on Wear
and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction. third type of stick-slip can be due to spatial periodicity of the
Current edition approved May 1, 2009. Published May 2009. Originally
friction coefficient along the path of contact. Random varia-
approved in 1996. Last previous edition approved in 2004 as G143–03(2004). DOI:
tions in friction force measurement do not constitute stick-slip.
10.1520/G0143-03R09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.6 triboelement, n—one of two or more solid bodies
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
which comprise a sliding, rolling, or abrasive contact, or a
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. body subjected to impingement or cavitation. G40
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G143 − 03 (2009)
3.1.6.1 Discussion—Contacting triboelements may be in
direct contact, or may be separated by an intervening lubricant,
oxide, or other film that affects tribological interactions be-
tween them.
3.1.7 tribosystem, n—any system that contains one or more
triboelements, including all mechanical, chemical, and envi-
ronmental factors relevant to tribological behavior. G40
4. Summary of Test Method
4.1 This test method can be used to measure the friction
characteristics of a flexible web as it slides on a cylindrical
surface.Thewebconformstothecylindricalsurfaceinthearea
of wrap.
4.2 The test method is conducted on a narrow web or strip
taken from a web of interest. One end of the strip is draped
FIG. 1 Schematic of Capstan Friction Test
over a stationary cylinder and the other end is affixed to a force
measuring device.Amass is applied to the free end of the strip
and the strip is pulled by a mechanism that moves the force
transducer perpendicular to the long axis of the cylindrical
surface. The force encountered in pulling the strip in contact
with the stationary cylinder (roller) is continuously measured
and recorded. The static and kinetic coefficients of friction are
calculated from the force measured by the force transducer.
5. Significance and Use
5.1 This test method is intended to simulate the slip of a
flexible web on a roller in a machine or tribosystem that
conveys web materials. Flexible webs such as plastic sheeting,
paper,elastomers,metalfoils,andclothareoftentransportedin
manufacturing processes by combinations of driving and idler
rollers. The friction characteristics of the web/roller interface
often affects the web transport process. If the web/roller
friction is too low, the web can slip on the rollers and be
damaged or damage the roller. High friction on the other hand,
can lead to steering problems and overloading of driving
motors.
5.2 This test method can be used to rank rollers for their
FIG. 2 Use of Tensile Test Machine to Perform the Capstan Fric-
ability to resist slip versus a particular web material (high tion Test
friction). Conversely this test method can assess web materials
or web surface coatings such as waxes and lubricants. In this
6.2 Force Measurement—Commercially available or home-
latter case, the goal may be a low-friction product made from
made strain gage or similar force transducers are acceptable.
a web (film, magnetic media, paper, and so forth).
The device should be linear in the force range anticipated in
testing and the transducer shall be calibrated with known
5.3 If a tribosystem involves transport of a flexible web on
masses or a similar system for each use.
a roller, this is an appropriate test to use to measure the friction
6.2.1 Force transducers shall be accurate within 1 % of the
characteristics of the roller/web couple.
rated scale of the device and should have overload protection.
6. Apparatus The friction force during the entire test should be recorded.
(Warning—Digital filters can alter the force data to the point
6.1 Two possible configurations of the test are shown in
where the data are not valid.Analog strip chart recorders have
Figs. 1 and 2. The essential features of the apparatus are:
been shown to be acceptable recording devices for this test
6.1.1 A force measuring device attached to one member of
method. (See Guide G163 for details on digital data acquisi-
the friction couple,
tion))
6.1.2 A stationary cylindrical surface to be used as one
member of the friction couple, 6.3 Cylindrical Surface—The recommended diameter of the
6.1.3 A system to move the flexible strip (web) member of test cylinder should be the same diameter as the rollers or
the friction couple, and curved surface that is simulated in the friction test. The
6.1.4 Masses to be used to tension the free end of the test cylinder surface texture and material of construction should be
strip. the same as the tribosystem of interest. If materials are being
G143 − 03 (2009)
evaluated without simulating a particular tribosystem, the test 7.1.1 Clean the roller surface in a manner that is consistent
roller can be the same as the roller used in the interlaboratory with the application that is under simulation. Cut virgin strips
tests of this test method: 100-mm diameter (100 mm long), from the test web as the other friction member. Take care not
50-µm thick hard coated (thick hard anodize) 6061-T6 alumi- to fingerprint or alter the test surface in handling the web.
num with a surface roughness of 0.75 to 1 µm Ra (measured
Convenient sample dimensions are 25 mm wide with a length
parallel to the cylinder’s axis; surface was lathe generated). of about 500 mm. Practice E122 or other statistical methods
can be used to determine the necessary number of test
6.4 Sliding Motion—The device shown schematically in
replicates. Three is the minimum.
Fig. 1 uses a linear motor to pull the test strip. The cylinder is
7.1.2 Do not clean the web specimen unless that is part of
stationary. Any device with controlled acceleration and veloc-
thestudy.Ifpaperorplasticsheetsarebeingtested,theyshould
ity is acceptable.Aball screw driven by a variable speed motor
be tested with untouched as-manufactured surfaces. Cut the
is suitable as is the crosshead on a tensile testing machine. In
web specimen in such a fashion that there is no edge burr on
the latter case, it may be necessary to use a sheave with a
the side that contacts the roller. This is extremely important.
free-wheeling rolling element bearing to transfer the motion
Ensure that the edges of the strip are parallel and in the desired
from a vertical to horizontal plane (see Fig. 2).
orientation with respect to the long axis of the host web. A
NOTE 1—Some devices rotate the cylinder and hold the web with a
useful tool for sample preparation is to affix two single-edged
force transducer. This was done in interlaboratory tests and produced the
razor blades to a block of wood spaced at the desired strip
same results as pulling the web over a stationary cylinder.
width.Thisdevicecanbeusedtocutsamplesfromthinplastic,
6.5 Tensioning Mass—Ordinary masses from balances and
cloth, and paper webs. The interlaboratory tests were con-
similar laboratory equipment are suitable for tensioning. It is
ducted with web strips that were 25 mm in width and 500 mm
imperative to attach the masses and the friction transducers
long.
with a device that prevents lateral motion of the test strip.
Bridle devices such as the one shown in Fig. 3 allow a straight
7.2 Mounting the Specimen—Affix one end of the web strip
pulloftheteststrip.Iflateralslipoccursinaparticulartest,the
tothebridleendoftheforcetransducer;drapethestripoverthe
results will probably be different from a test in which this
test roller (cylindrical surface), and apply the desired tension-
unwanted slip does not occur.
ing mass.Avoid clamp systems that have significant elasticity.
If a tensile-testing machine is used to produce motion, flexible
6.6 Test Environment—The friction characteristics of some
steel cable can be used to pull the strip. Ensure that the strip is
web/roller couples can be affected by the ambient temperature
pulled straight (aligned with the web tension) within 61 mm.
andrelativehumidity.Bothfrictionandtemperatureatthetime
Markers can be used on the test roller to determine if tracking
of testing shall be recorded and, if the tribosystem that is to be
is within the 1-mm limit.
simulated involves some special environment, then this should
besimulated.Testsamplesshouldbeincubatedforanadequate
7.3 Setting the Sliding Parameters:
timetoreachequilibriumintheintendedtestenvironmentprior
7.3.1 Velocity—The capstan friction tester allows selection
to testing. Twenty four hours is a minimum incubation period.
ofslidingvelocity,slidingdistance,andfree-endtensiononthe
6.7 Calibration—A suitable system for calibration of the
strip. It is recommended that values for these parameters be
force transducer is to mount the transducer vertically and
selected to simulate the system of interest.The sliding velocity
simply apply a series of known weights on the transducer with
between webs and transport or drive rollers in manufacturing
the force recording device running. Make sure that the output
machines is usually in the range from a fraction of a percent of
of the force transducer is linearly proportional to the applied
the web speed to a worst case of 10 % of the web speed. (For
force over the range of forces to be measured. Calibrate using
example, if a web conveyance system is being simulated with
weights that produce force comparable in magnitude to the
a web speed of 1 m/s, a low-end test velocity may be 5 mm/s
forces anticipated in the friction test.
andthehigh-endtestvelocity0.1m/s.)Thereisavelocitylimit
in this type of test. High speed will cause instability in the
7. Test Procedure
contact of the web with the conforming cylindrical surface.
7.1 Specimen Preparation:
Users can test the velocity limits of their system, but 0.1 m/s is
about the limit of the systems that were used in interlaboratory
testing. A continuous loop test (Test Method D3108) is more
appropriate for high sliding velocities.
7.3.2 Sliding Distance—If the goal of this test method is the
static coefficient of friction, the test can be stopped after a few
millimetres of sliding. If the goal of this test method is both the
static and the kinetic coefficients of friction, it is desirable to
slide for as long a distance as the test setup will allow.With the
test setup shown in Fig. 1, the maximum travel on commercial
linear motors is about 0.5 m. The allowable motion on the
pulling device is the limiting factor on sliding distance.
Interlaboratory tests were conducted with a sliding distance of
FIG. 3 Method for Gripping the Test Strip 150mm.Thisistherecommendedslidingdistanceforthistest.
G143 − 03 (2009)
7.3.3 Test Tension—The tensioning mass aff
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:G143–03 (Reapproved 2004) Designation:G143–03 (Reapproved 2009)
Standard Test Method for
Measurement of Web/Roller Friction Characteristics
This standard is issued under the fixed designation G 143; 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
1.1 This test method covers the simulation of a roller/web transport tribosystem and the measurement of the static and kinetic
coefficient of friction of the web/roller couple when sliding occurs between the two.The objective of this test method is to provide
users with web/roller friction information that can be used for process control, design calculations, and for any other function
where web/roller friction needs to be known.
1.2The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
D883ASTM Standards:
D 883 Terminology Relating to Plastics
D 1894 Test Method for Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting
D 3108 Test Method for Coefficient of Friction, Yarn to Solid Material
E8 Test Methods for Tension Testing of Metallic Materials
E 122 Practice for Choice of Calculating Sample Size to Estimate, With a Specified Tolerable Error, Precision, theAverage for
a Characteristic of a Lot or Process
E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
G40
G40 Terminology Relating to Wear and Erosion
G115 Guide for Measuring and Reporting Friction Coefficients
G117 Guide for Calculating and Reporting Measures of Precision Using Data from Interlaboratory Wear or Erosion Tests
G163
G 163 Guide for Digital Data Acquisition in Wear and Friction Measurements
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 blocking, n—unintentional adhesion between plastic films or between a film and another surface. D883
3.1.2 coeffıcient of friction, µ, n—in tribology—the dimensionless ratio of the friction force (F) between two bodies to the
normal force (N) pressing these bodies together. G40
3.1.3 friction force, n—the resisting force tangential to the interface between two bodies when, under the action of external
force, one body moves or tends to move relative to the other. G40
3.1.4 kinetic coeffıcient of friction, n— the coefficient of friction under conditions of macroscopic relative motion between two
bodies. G40
3.1.5 stick-slip, n—a cyclic fluctuation in the magnitudes of friction force and relative velocity between two elements in sliding
contact, usually associated with a relaxation oscillation dependent on elasticity in the tribosystem and on a decrease of the
This test method is under the jurisdiction of ASTM Committee G02 on Wear and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction .
Current edition approved NovMay 1, 2004.2009. Published November 2004.May 2009. Originally approved in 1996. Last previous edition approved in 20032004 as
G143–03.G 143–03(2004).
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G143–03 (2009)
coefficient of friction with onset of sliding or with increase of sliding velocity. G40
3.1.5.1 Discussion—Classical or true stick-slip, in which each cycle consists of a stage of actual stick followed by a stage of
overshoot slip, requires that the kinetic coefficient is lower than the static coefficient. A modified form of relaxation oscillation,
with near-harmonic fluctuation in motion, can occur when the kinetic coefficient of friction decreases gradually with increasing
velocity within a certain velocity range.Athird type of stick-slip can be due to spatial periodicity of the friction coefficient along
the path of contact. Random variations in friction force measurement do not constitute stick-slip.
3.1.6 triboelement, n—one of two or more solid bodies which comprise a sliding, rolling, or abrasive contact, or a body
subjected to impingement or cavitation. G40
3.1.6.1 Discussion—Contacting triboelements may be in direct contact, or may be separated by an intervening lubricant, oxide,
or other film that affects tribological interactions between them.
3.1.7 tribosystem, n—any system that contains one or more triboelements, including all mechanical, chemical, and
environmental factors relevant to tribological behavior. G40
4. Summary of Test Method
4.1 This test method can be used to measure the friction characteristics of a flexible web as it slides on a cylindrical surface.
The web conforms to the cylindrical surface in the area of wrap.
4.2 The test method is conducted on a narrow web or strip taken from a web of interest. One end of the strip is draped over
a stationary cylinder and the other end is affixed to a force measuring device. A mass is applied to the free end of the strip and
the strip is pulled by a mechanism that moves the force transducer perpendicular to the long axis of the cylindrical surface. The
force encountered in pulling the strip in contact with the stationary cylinder (roller) is continuously measured and recorded. The
static and kinetic coefficients of friction are calculated from the force measured by the force transducer.
5. Significance and Use
5.1 This test method is intended to simulate the slip of a flexible web on a roller in a machine or tribosystem that conveys web
materials. Flexible webs such as plastic sheeting, paper, elastomers, metal foils, and cloth are often transported in manufacturing
processes by combinations of driving and idler rollers. The friction characteristics of the web/roller interface often affects the web
transport process. If the web/roller friction is too low, the web can slip on the rollers and be damaged or damage the roller. High
friction on the other hand, can lead to steering problems and overloading of driving motors.
5.2 This test method can be used to rank rollers for their ability to resist slip versus a particular web material (high friction).
Conversely this test method can assess web materials or web surface coatings such as waxes and lubricants. In this latter case, the
goal may be a low-friction product made from a web (film, magnetic media, paper, and so forth).
5.3 If a tribosystem involves transport of a flexible web on a roller, this is an appropriate test to use to measure the friction
characteristics of the roller/web couple.
6. Apparatus
6.1 Two possible configurations of the test are shown in Figs. 1 and 2. The essential features of the apparatus are:
6.1.1 A force measuring device attached to one member of the friction couple,
6.1.2 A stationary cylindrical surface to be used as one member of the friction couple,
6.1.3 A system to move the flexible strip (web) member of the friction couple, and
6.1.4 Masses to be used to tension the free end of the test strip.
6.2 Force Measurement—Commercially available or homemade strain gage or similar force transducers are acceptable. The
device should be linear in the force range anticipated in testing and the transducer shall be calibrated with known masses or a
similar system for each use.
FIG. 1 Schematic of Capstan Friction Test
G143–03 (2009)
FIG. 2 Use of Tensile Test Machine to Perform the Capstan
Friction Test
6.2.1 Force transducers shall be accurate within 1 % of the rated scale of the device and should have overload protection. The
friction force during the entire test should be recorded. ( Warning—Digital filters can alter the force data to the point where the
dataarenotvalid.Analogstripchartrecordershavebeenshowntobeacceptablerecordingdevicesforthistestmethod.(SeeGuide
G 163 for details on digital data acquisition))
6.3 Cylindrical Surface—The recommended diameter of the test cylinder should be the same diameter as the rollers or curved
surface that is simulated in the friction test. The cylinder surface texture and material of construction should be the same as the
tribosystem of interest. If materials are being evaluated without simulating a particular tribosystem, the test roller can be the same
as the roller used in the interlaboratory tests of this test method: 100-mm diameter (100 mm long), 50-µm thick hard coated (thick
hard anodize) 6061-T6 aluminum with a surface roughness of 0.75 to 1 µm Ra (measured parallel to the cylinder’s axis; surface
was lathe generated).
6.4 Sliding Motion—The device shown schematically in Fig. 1 uses a linear motor to pull the test strip. The cylinder is
stationary. Any device with controlled acceleration and velocity is acceptable. A ball screw driven by a variable speed motor is
suitable as is the crosshead on a tensile testing machine. In the latter case, it may be necessary to use a sheave with a free-wheeling
rolling element bearing to transfer the motion from a vertical to horizontal plane (see Fig. 2).
NOTE 1—Some devices rotate the cylinder and hold the web with a force transducer. This was done in interlaboratory tests and produced the same
results as pulling the web over a stationary cylinder.
6.5 Tensioning Mass—Ordinary masses from balances and similar laboratory equipment are suitable for tensioning. It is
imperative to attach the masses and the friction transducers with a device that prevents lateral motion of the test strip. Bridle
devices such as the one shown in Fig. 3 allow a straight pull of the test strip. If lateral slip occurs in a particular test, the results
will probably be different from a test in which this unwanted slip does not occur.
6.6 Test Environment—The friction characteristics of some web/roller couples can be affected by the ambient temperature and
relative humidity. Both friction and temperature at the time of testing shall be recorded and, if the tribosystem that is to be
FIG. 3 Method for Gripping the Test Strip
G143–03 (2009)
simulatedinvolvessomespecialenvironment,thenthisshouldbesimulated.Testsamplesshouldbeincubatedforanadequatetime
to reach equilibrium in the intended test environment prior to testing. Twenty four hours is a minimum incubation period.
6.7 Calibration—Asuitablesystemforcalibrationoftheforcetransduceristomountthetransducerverticallyandsimplyapply
a series of known weights on the transducer with the force recording device running. Make sure that the output of the force
transducerislinearlyproportionaltotheappliedforceovertherangeofforcestobemeasured.Calibrateusingweightsthatproduce
force comparable in magnitude to the forces anticipated in the friction test.
7. Test Procedure
7.1 Specimen Preparation:
7.1.1 Clean the roller surface in a manner that is consistent with the application that is under simulation. Cut virgin strips from
the test web as the other friction member. Take care not to fingerprint or alter the test surface in handling the web. Convenient
sample dimensions are 25 mm wide with a length of about 500 mm. Practice E 122 or other statistical methods can be used to
determine the necessary number of test replicates. Three is the minimum.
7.1.2 Do not clean the web specimen unless that is part of the study. If paper or plastic sheets are being tested, they should be
tested with untouched as-manufactured surfaces. Cut the web specimen in such a fashion that there is no edge burr on the side that
contacts the roller. This is extremely important. Ensure that the edges of the strip are parallel and in the desired orientation with
respect to the long axis of the host web. A useful tool for sample preparation is to affix two single-edged razor blades to a block
of wood spaced at the desired strip width. This device can be used to cut samples from thin plastic, cloth, and paper webs. The
interlaboratory tests were conducted with web strips that were 25 mm in width and 500 mm long.
7.2 Mounting the Specimen—Affix one end of the web strip to the bridle end of the force transducer; drape the strip over the
test roller (cylindrical surface), and apply the desired tensioning mass. Avoid clamp systems that have significant elasticity. If a
tensile-testing machine is used to produce motion, flexible steel cable can be used to pull the strip. Ensure that the strip is pulled
straight (aligned with the web tension) within 61 mm. Markers can be used on the test roller to determine if tracking is within
the 1-mm limit.
7.3 Setting the Sliding Parameters :
7.3.1 Velocity—Thecapstanfrictiontesterallowsselectionofslidingvelocity,slidingdistance,andfree-endtensiononthestrip.
It is recommended that values for these parameters be selected to simulate the system of interest. The sliding velocity between
webs and transport or drive rollers in manufacturing machines is usually in the range from a fraction of a percent of the web speed
to a worst case of 10 % of the web speed. (For example, if a web conveyance system is being simulated with a web speed of 1
m/s, a low-end test velocity may be 5 mm/s and the high-end test velocity 0.1 m/s.) There is a velocity limit in this type of test.
Highspeedwillcauseinstabilityinthecontactofthewebwiththeconformingcylindricalsurface.Userscantestthevelocitylimits
of their system, but 0.1 m/s is about the limit of the systems that were used in interlaboratory testing.Acontinuous loop test (Test
Method D 3108) is more appropriate for high sliding velocities.
7.3.2 Sliding Distance—If the goal of this test method is the static coefficient of friction, the test can be stopped after a few
millimetres of sliding. If the goal of this t
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:G143–96 Designation:G143–03 (Reapproved 2009)
Standard Test Method for
Measurement of Web/Roller Friction Characteristics
This standard is issued under the fixed designation G 143; 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
1.1This test method can be used to simulate a roller/web transport tribosystem and to measure the static and kinetic coefficient
of friction of the web/roller couple when sliding occurs between the two.The objective of this test method is to provide users with
web/roller friction information that can be used for process control, design calculations, and for any other function where
web/roller friction needs to be known.
1.2
1.1 This test method covers the simulation of a roller/web transport tribosystem and the measurement of the static and kinetic
coefficient of friction of the web/roller couple when sliding occurs between the two.The objective of this test method is to provide
users with web/roller friction information that can be used for process control, design calculations, and for any other function
where web/roller friction needs to be known.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
D 883 Terminology Relating to Plastics
D 1894 Test Method for Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting
D 3108 Test Method for Coefficient of Friction, Yarn to MetalSolid Material
E8 Test Methods for Tension Testing of Metallic Materials
E 122 PracticeforChoiceofSampleSizetoEstimateaMeasureofQualityforaLotorProcessPracticeforCalculatingSample
Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process
E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
G40 Terminology Relating to Erosion and Wear Terminology Relating to Wear and Erosion
G115 Guide for Measuring and Reporting Friction Coefficients
G117 Guide for Calculating and Reporting Measures of Precision Using Data from Interlaboratory Wear or Erosion Tests
Guide for Calculating and Reporting Measures of Precision Using Data from Interlaboratory Wear or Erosion Tests
G 163 Guide for Digital Data Acquisition in Wear and Friction Measurements
3. Terminology
3.1Definitions:
3.1 Definitions of Terms Specific to This Standard:
3.1.1 blockblocking, v—in plastics , the tendency for one plastic surface to adhere to another surface (usually another plastic)
after being in intimate contact for some residence time. Sometimes it takes hours, sometimes months. n—unintentional adhesion
between plastic films or between a film and another surface. D883
3.1.2 coeffıcient of friction, µ, n—in tribology—the dimensionless ratio of the friction force (F) between two bodies to the
normal force (N) pressing these bodies together. G40
3.1.3 friction force, n—the resisting force tangential to the interface between two bodies when, under the action of external
force, one body moves or tends to move relative to the other. G40
This test method is under the jurisdiction of ASTM Committee G-2 G02 on Wear and Erosion and is the direct responsibility of Subcommittee G02.50 on Erosion .
Current edition approved Oct. 10, 1996. Published December 1996.on Friction .
Current edition approved May 1, 2009. Published May 2009. Originally approved in 1996. Last previous edition approved in 2004 as G 143–03(2004).
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 08.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G143–03 (2009)
3.1.4 kinetic coeffıcient of friction, n— the coefficient of friction under conditions of macroscopic relative motion between two
bodies. G40
3.1.5 stick-slip, n—a cyclic fluctuation in the magnitudes of friction force and relative velocity between two elements in sliding
contact, usually associated with a relaxation oscillation dependent on elasticity in the tribosystem and on a decrease of the
coefficient of friction with onset of sliding or with increase of sliding velocity. G40
3.1.5.1 Discussion—Classical or true stick-slip, in which each cycle consists of a stage of actual stick followed by a stage of
overshoot slip, requires that the kinetic coefficient is lower than the static coefficient. A modified form of relaxation oscillation,
with near-harmonic fluctuation in motion, can occur when the kinetic coefficient of friction decreases gradually with increasing
velocity within a certain velocity range.Athird type of stick-slip can be due to spatial periodicity of the friction coefficient along
the path of contact. Random variations in friction force measurement do not constitute stick-slip.
3.1.6 triboelement, n—one of two or more solid bodies which comprise a sliding, rolling, or abrasive contact, or a body
subjected to impingement or cavitation. G40
3.1.6.1 Discussion—Contacting triboelements may be in direct contact, or may be separated by an intervening lubricant, oxide,
or other film that affects tribological interactions between them.
3.1.7 tribosystem, n—any system that contains one or more triboelements, including all mechanical, chemical, and
environmental factors relevant to tribological behavior. G40
4. Summary of Test Method
4.1 This test method can be used to measure the friction characteristics of a flexible web as it slides on a cylindrical surface.
The web conforms to the cylindrical surface in the area of wrap.
4.2 The test method is conducted on a narrow web or strip taken from a web of interest. One end of the strip is draped over
a stationary cylinder and the other end is affixed to a force measuring device. A mass is applied to the free end of the strip and
the strip is pulled by a mechanism that moves the force transducer perpendicular to the long axis of the cylindrical surface. The
force encountered in pulling the strip in contact with the stationary cylinder (roller) is continuously measured and recorded. The
static and kinetic coefficients of friction are calculated from the force measured by the force transducer.
5. Significance and Use
5.1 This test method is intended to simulate the slip of a flexible web on a roller in a machine or tribosystem that conveys web
materials. Flexible webs such as plastic sheeting, paper, elastomers, metal foils, and cloth are often transported in manufacturing
processes by combinations of driving and idler rollers. The friction characteristics of the web/roller interface often affects the web
transport process. If the web/roller friction is too low, the web can slip on the rollers and be damaged or damage the roller. High
friction on the other hand, can lead to steering problems and overloading of driving motors.
5.2 This test method can be used to rank rollers for their ability to resist slip versus a particular web material (high friction).
Conversely this test method can assess web materials or web surface coatings such as waxes and lubricants. In this latter case, the
goal may be a low-friction product made from a web (film, magnetic media, paper, and so forth).
5.3 If a tribosystem involves transport of a flexible web on a roller, this is an appropriate test to use to measure the friction
characteristics of the roller/web couple.
6. Apparatus
6.1 Two possible configurations of the test are shown in Figs. 1 and 2. The essential features of the apparatus are:
6.1.1 A force measuring device attached to one member of the friction couple. couple,
FIG. 1 Schematic of Capstan Friction Test
G143–03 (2009)
FIG. 2 Use of Tensile Test Machine to Perform the Capstan
Friction Test
6.1.2 A stationary cylindrical surface to be used as one member of the friction couple,
6.1.3 A system to move the flexible strip (web) member of the friction couple, and
6.1.4 Masses to be used to tension the free end of the test strip.
6.2 Force Measurement—Commercially available or homemade strain gage or similar force transducers are acceptable. The
device should be linear in the force range anticipated in testing and the transducer shall be calibrated with known masses or a
similar system for each use.
6.2.1 Force transducers shall be accurate within 1 % of the rated scale of the device and should have overload protection. The
friction force during the entire test should be recorded. Note1—Caution:( Warning—Digital filters can alter the force data to the
point where the data are not valid. Analog strip chart recorders have been shown to be acceptable recording devices for this test
method. (See Guide G 163 for details on digital data acquisition))
6.3 Cylindrical Surface—The recommended diameter of the test cylinder should be the same diameter as the rollers or curved
surface that is simulated in the friction test. The cylinder surface texture and material of construction should be the same as the
tribosystem of interest. If materials are being evaluated without simulating a particular tribosystem, the test roller can be the same
as the roller used in the interlaboratory tests of this test method: 100-mm diameter (100 mm long), 50-µm thick hard coated (thick
hard anodize) 6061-T6 aluminum with a surface roughness of 0.75 to 1 µm Ra (measured parallel to the cylinder’s axis; surface
was lathe generated).
6.4 Sliding Motion—The device shown schematically in Fig. 1 uses a linear motor as the device to pull the test strip. The
cylinder is stationary.Any device with controlled acceleration and velocity is acceptable.Aball screw driven by a variable speed
motor is suitable as is the crosshead on a tensile testing machine. In the latter case, it may be necessary to use a sheave with a
free-wheeling rolling element bearing to transfer the motion from a vertical to horizontal plane (see Fig. 2).
NOTE2—Some 1—Some devices rotate the cylinder and hold the web with a force transducer. This was done in interlaboratory tests and produced the
same results as pulling the web over a stationary cylinder.
6.5 Tensioning Mass—Ordinary masses from balances and similar laboratory equipment are suitable for tensioning. It is
imperativetoattachthemassesandthefrictiontransducerswithadevicethatpreventslateralmotionoftheteststrip.SwivelBridle
devices such as the one shown in Fig. 3 allow a straight pull of the test strip. If lateral slip occurs in a particular test, the results
will probably be different from a test in which this unwanted slip does not occur.
6.6 Test Environment—The friction characteristics of some web/roller couples can be affected by the ambient temperature and
relative humidity. Both friction and temperature at the time of testing shall be recorded and, if the tribosystem that is to be
simulatedinvolvessomespecialenvironment,thenthisshouldbesimulated.Testsamplesshouldbeincubatedforanadequatetime
to reach equilibrium in the intended test environment prior to testing. Twenty four hours is a minimum incubation period.
6.7 Calibration—Asuitablesystemforcalibrationoftheforcetransduceristomountthetransducerverticallyandsimplyapply
a series of known weights on the transducer with the force recording device running. Make sure that the output of the force
transducerislinearlyproportionaltotheappliedforceovertherangeofforcestobemeasured.Calibrateusingweightsthatproduce
force comparable in magnitude to the forces anticipated in the friction test.
G143–03 (2009)
FIG. 3 Method for Gripping the Test Strip
7. Test Procedure
7.1 Specimen Preparation:
7.1.1 Clean the roller surface in a manner that is consistent with the application that is under simulation. Cut virgin strips from
the test web as the other friction member. Take care not to fingerprint or alter the test surface in handling the web. Convenient
sample dimensions are 25 mm wide with a length of about 500 mm. Practice E 122 or other statistical methods can be used to
determine the necessary number of test replicates. Three is the minimum.
7.1.2 Do not clean the web specimen unless that is part of the study. If paper or plastic sheets are being tested, they should be
tested with untouched as-manufactured surfaces. Cut the web specimen in such a fashion that there is no edge burr on the side that
contacts the roller. This is extremely important. Ensure that the edges of the strip are parallel and in the desired orientation with
respect to the long axis of the host web. A useful tool for sample preparation is to affix two single-edged razor blades to a block
of wood spaced at the desired strip width. This device can be used to cut samples from thin plastic, cloth, and paper webs. The
interlaboratory tests were conducted with web strips that were 25 mm in width and 500 mm long.
7.2 Mounting the Specimen—Affix one end of the web strip to the swivelbridle end of the force transducer; drape the strip over
the test roller (cylindrical surface), and apply the desired tensioning mass.Avoid clamp systems that have significant elasticity. If
a tensiontensile-testing machine is used to produce motion, flexible steel cable can be used to pull the strip. Ensure that the strip
is pulled straight (aligned with the web tension) within 61 mm. Markers can be used on the test roller to determine if tracking
is within the 1-mm limit.
7.3 Setting the Sliding Parameters :
7.3.1 Velocity—Thecapstanfrictiontesterallowsselectionofslidingvelocity,slidingdistance,andfree-endtensiononthestrip.
It is recommended that values for these parameters be selected to simulate the system of interest. The sliding velocity between
webs and transport or drive rollers in manufacturing machines is usually i
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.