ASTM G143-03(2018)
(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
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.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G143 − 03 (Reapproved 2018)
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 Specified Precision, the Average for a Characteristic of a
Lot or Process
1.1 This test method covers the simulation of a roller/web
E177 Practice for Use of the Terms Precision and Bias in
transport tribosystem and the measurement of the static and
ASTM Test Methods
kinetic coefficient of friction of the web/roller couple when
E691 Practice for Conducting an Interlaboratory Study to
sliding occurs between the two. The objective of this test
Determine the Precision of a Test Method
method is to provide users with web/roller friction information
G40 Terminology Relating to Wear and Erosion
that can be used for process control, design calculations, and
G115 Guide for Measuring and Reporting Friction Coeffi-
for any other function where web/roller friction needs to be
cients
known.
G117 Guide for Calculating and Reporting Measures of
1.2 The values stated in SI units are to be regarded as
Precision Using Data from Interlaboratory Wear or Ero-
standard. No other units of measurement are included in this
sion Tests (Withdrawn 2016)
standard.
G163 Guide for Digital Data Acquisition in Wear and
1.3 This standard does not purport to address all of the Friction Measurements (Withdrawn 2016)
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.1 Definitions of Terms Specific to This Standard:
mine the applicability of regulatory limitations prior to use.
3.1.1 blocking, n—unintentional adhesion between plastic
1.4 This international standard was developed in accor-
films or between a film and another surface. D883
dance with internationally recognized principles on standard-
3.1.2 coeffıcient of friction, µ, n—in tribology—the dimen-
ization established in the Decision on Principles for the
sionlessratioofthefrictionforce(F)betweentwobodiestothe
Development of International Standards, Guides and Recom-
normal force (N) pressing these bodies together. G40
mendations issued by the World Trade Organization Technical
3.1.3 friction force, n—the resisting force tangential to the
Barriers to Trade (TBT) Committee.
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
friction under conditions of macroscopic relative motion be-
D1894 Test Method for Static and Kinetic Coefficients of
tween two bodies. G40
Friction of Plastic Film and Sheeting
D3108/D3108M Test Method for Coefficient of Friction, 3.1.5 stick-slip, n—a cyclic fluctuation in the magnitudes of
friction force and relative velocity between two elements in
Yarn to Solid Material
E8/E8M Test Methods for Tension Testing of Metallic Ma- sliding contact, usually associated with a relaxation oscillation
dependent on elasticity in the tribosystem and on a decrease of
terials
the coefficient of friction with onset of sliding or with increase
E122 Practice for Calculating Sample Size to Estimate,With
of sliding velocity. G40
3.1.5.1 Discussion—Classical or true stick-slip, in which
This test method is under the jurisdiction of ASTM Committee G02 on Wear
each cycle consists of a stage of actual stick followed by a
and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction.
stage of overshoot slip, requires that the kinetic coefficient is
CurrenteditionapprovedJune1,2018.PublishedJuly2018.Originallyapproved
lower than the static coefficient.Amodified form of relaxation
in 1996. Last previous edition approved in 2013 as G143 – 03 (2013). DOI:
oscillation, with near-harmonic fluctuation in motion, can
10.1520/G0143-03R18.
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
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G143 − 03 (2018)
occur when the kinetic coefficient of friction decreases gradu-
ally with increasing velocity within a certain velocity range.A
third type of stick-slip can be due to spatial periodicity of the
friction coefficient along the path of contact. Random varia-
tions 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 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
FIG. 1 Schematic of Capstan Friction Test
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
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
FIG. 2 Use of Tensile Test Machine to Perform the Capstan Fric-
tion Test
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
6.1.1 A force measuring device attached to one member of
damaged or damage the roller. High friction on the other hand,
the friction couple,
can lead to steering problems and overloading of driving
6.1.2 A stationary cylindrical surface to be used as one
motors.
member of the friction couple,
5.2 This test method can be used to rank rollers for their
6.1.3 A system to move the flexible strip (web) member of
ability to resist slip versus a particular web material (high
the friction couple, and
friction). Conversely this test method can assess web materials
6.1.4 Masses to be used to tension the free end of the test
or web surface coatings such as waxes and lubricants. In this
strip.
latter case, the goal may be a low-friction product made from
6.2 Force Measurement—Commercially available or home-
a web (film, magnetic media, paper, and so forth).
made strain gage or similar force transducers are acceptable.
5.3 If a tribosystem involves transport of a flexible web on
The device should be linear in the force range anticipated in
a roller, this is an appropriate test to use to measure the friction
testing and the transducer shall be calibrated with known
characteristics of the roller/web couple.
masses or a similar system for each use.
6.2.1 Force transducers shall be accurate within 1 % of the
6. Apparatus
rated scale of the device and should have overload protection.
6.1 Two possible configurations of the test are shown in The friction force during the entire test should be recorded.
Figs. 1 and 2. The essential features of the apparatus are: (Warning—Digital filters can alter the force data to the point
G143 − 03 (2018)
where the data are not valid.Analog strip chart recorders have simply apply a series of known weights on the transducer with
been shown to be acceptable recording devices for this test the force recording device running. Make sure that the output
method. (See Guide G163 for details on digital data acquisi- of the force transducer is linearly proportional to the applied
tion)) force over the range of forces to be measured. Calibrate using
weights that produce force comparable in magnitude to the
6.3 Cylindrical Surface—The recommended diameter of the
forces anticipated in the friction test.
test cylinder should be the same diameter as the rollers or
curved surface that is simulated in the friction test. The
7. Test Procedure
cylinder surface texture and material of construction should be
7.1 Specimen Preparation:
the same as the tribosystem of interest. If materials are being
7.1.1 Clean the roller surface in a manner that is consistent
evaluated without simulating a particular tribosystem, the test
with the application that is under simulation. Cut virgin strips
roller can be the same as the roller used in the interlaboratory
from the test web as the other friction member. Take care not
tests of this test method: 100-mm diameter (100 mm long),
to fingerprint or alter the test surface in handling the web.
50-µm thick hard coated (thick hard anodize) 6061-T6 alumi-
Convenient sample dimensions are 25 mm wide with a length
num with a surface roughness of 0.75 to 1 µm Ra (measured
of about 500 mm. Practice E122 or other statistical methods
parallel to the cylinder’s axis; surface was lathe generated).
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.
7.2 Mounting the Specimen—Affix one end of the web strip
Bridle devices such as the one shown in Fig. 3 allow a straight
tothebridleendoftheforcetransducer;drapethestripoverthe
pulloftheteststrip.Iflateralslipoccursinaparticulartest,the
test roller (cylindrical surface), and apply the desired tension-
results will probably be different from a test in which this
ing mass.Avoid clamp systems that have significant elasticity.
unwanted slip does not occur.
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
7.3 Setting the Sliding Parameters:
besimulated.Testsamplesshouldbeincubatedforanadequate
7.3.1 Velocity—The capstan friction tester allows selection
timetoreachequilibriumintheintendedtestenvironmentprior
ofslidingvelocity,slidingdistance,andfree-endtensiononthe
to testing. Twenty four hours is a minimum incubation period.
strip. It is recommended that values for these parameters be
6.7 Calibration—A suitable system for calibration of the
selected to simulate the system of interest.The sliding velocity
force transducer is to mount the transducer vertically and
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
andthehigh-endtestvelocity0.1m/s.)Thereisavelocitylimit
in this type of test. High speed will cause instability in the
contact of the web with the conforming cylindrical surface.
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/D3108M)
is more appropriate for high sliding velocities.
7.3.2 Sliding Distance—If the goal of this test method is the
FIG. 3 Method for Gripping the Test Strip static coefficient of friction, the test ca
...
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 2018)
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 Specified Precision, the Average for a Characteristic of a
Lot or Process
1.1 This test method covers the simulation of a roller/web
E177 Practice for Use of the Terms Precision and Bias in
transport tribosystem and the measurement of the static and
ASTM Test Methods
kinetic coefficient of friction of the web/roller couple when
E691 Practice for Conducting an Interlaboratory Study to
sliding occurs between the two. The objective of this test
Determine the Precision of a Test Method
method is to provide users with web/roller friction information
G40 Terminology Relating to Wear and Erosion
that can be used for process control, design calculations, and
G115 Guide for Measuring and Reporting Friction Coeffi-
for any other function where web/roller friction needs to be
cients
known.
G117 Guide for Calculating and Reporting Measures of
1.2 The values stated in SI units are to be regarded as
Precision Using Data from Interlaboratory Wear or Ero-
standard. No other units of measurement are included in this 3
sion Tests (Withdrawn 2016)
standard.
G163 Guide for Digital Data Acquisition in Wear and
1.3 This standard does not purport to address all of the
Friction Measurements (Withdrawn 2016)
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.1 Definitions of Terms Specific to This Standard:
mine the applicability of regulatory limitations prior to use.
3.1.1 blocking, n—unintentional adhesion between plastic
1.4 This international standard was developed in accor-
films or between a film and another surface. D883
dance with internationally recognized principles on standard-
3.1.2 coeffıcient of friction, µ, n—in tribology—the dimen-
ization established in the Decision on Principles for the
sionless ratio of the friction force (F) between two bodies to the
Development of International Standards, Guides and Recom-
normal force (N) pressing these bodies together. G40
mendations issued by the World Trade Organization Technical
3.1.3 friction force, n—the resisting force tangential to the
Barriers to Trade (TBT) Committee.
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
friction under conditions of macroscopic relative motion be-
D1894 Test Method for Static and Kinetic Coefficients of
tween two bodies. G40
Friction of Plastic Film and Sheeting
3.1.5 stick-slip, n—a cyclic fluctuation in the magnitudes of
D3108/D3108M Test Method for Coefficient of Friction,
Yarn to Solid Material friction force and relative velocity between two elements in
sliding contact, usually associated with a relaxation oscillation
E8/E8M Test Methods for Tension Testing of Metallic Ma-
dependent on elasticity in the tribosystem and on a decrease of
terials
the coefficient of friction with onset of sliding or with increase
E122 Practice for Calculating Sample Size to Estimate, With
of sliding velocity. G40
3.1.5.1 Discussion—Classical or true stick-slip, in which
This test method is under the jurisdiction of ASTM Committee G02 on Wear each cycle consists of a stage of actual stick followed by a
and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction.
stage of overshoot slip, requires that the kinetic coefficient is
Current edition approved June 1, 2018. Published July 2018. Originally approved
lower than the static coefficient. A modified form of relaxation
in 1996. Last previous edition approved in 2013 as G143 – 03 (2013). DOI:
oscillation, with near-harmonic fluctuation in motion, can
10.1520/G0143-03R18.
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
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G143 − 03 (2018)
occur when the kinetic coefficient of friction decreases gradu-
ally with increasing velocity within a certain velocity range. A
third type of stick-slip can be due to spatial periodicity of the
friction coefficient along the path of contact. Random varia-
tions 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 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
FIG. 1 Schematic of Capstan Friction Test
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
FIG. 2 Use of Tensile Test Machine to Perform the Capstan Fric-
tion Test
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
6.1.1 A force measuring device attached to one member of
damaged or damage the roller. High friction on the other hand,
the friction couple,
can lead to steering problems and overloading of driving
6.1.2 A stationary cylindrical surface to be used as one
motors.
member of the friction couple,
5.2 This test method can be used to rank rollers for their
6.1.3 A system to move the flexible strip (web) member of
ability to resist slip versus a particular web material (high
the friction couple, and
friction). Conversely this test method can assess web materials
6.1.4 Masses to be used to tension the free end of the test
or web surface coatings such as waxes and lubricants. In this
strip.
latter case, the goal may be a low-friction product made from
6.2 Force Measurement—Commercially available or home-
a web (film, magnetic media, paper, and so forth).
made strain gage or similar force transducers are acceptable.
5.3 If a tribosystem involves transport of a flexible web on
The device should be linear in the force range anticipated in
a roller, this is an appropriate test to use to measure the friction
testing and the transducer shall be calibrated with known
characteristics of the roller/web couple.
masses or a similar system for each use.
6.2.1 Force transducers shall be accurate within 1 % of the
6. Apparatus
rated scale of the device and should have overload protection.
6.1 Two possible configurations of the test are shown in The friction force during the entire test should be recorded.
Figs. 1 and 2. The essential features of the apparatus are: (Warning—Digital filters can alter the force data to the point
G143 − 03 (2018)
where the data are not valid. Analog strip chart recorders have simply apply a series of known weights on the transducer with
been shown to be acceptable recording devices for this test the force recording device running. Make sure that the output
method. (See Guide G163 for details on digital data acquisi- of the force transducer is linearly proportional to the applied
tion)) force over the range of forces to be measured. Calibrate using
weights that produce force comparable in magnitude to the
6.3 Cylindrical Surface—The recommended diameter of the
forces anticipated in the friction test.
test cylinder should be the same diameter as the rollers or
curved surface that is simulated in the friction test. The
7. Test Procedure
cylinder surface texture and material of construction should be
7.1 Specimen Preparation:
the same as the tribosystem of interest. If materials are being
7.1.1 Clean the roller surface in a manner that is consistent
evaluated without simulating a particular tribosystem, the test
with the application that is under simulation. Cut virgin strips
roller can be the same as the roller used in the interlaboratory
from the test web as the other friction member. Take care not
tests of this test method: 100-mm diameter (100 mm long),
to fingerprint or alter the test surface in handling the web.
50-µm thick hard coated (thick hard anodize) 6061-T6 alumi-
Convenient sample dimensions are 25 mm wide with a length
num with a surface roughness of 0.75 to 1 µm Ra (measured
of about 500 mm. Practice E122 or other statistical methods
parallel to the cylinder’s axis; surface was lathe generated).
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-
the study. If paper or plastic sheets are being tested, they should
ity is acceptable. A ball 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. This device can be used to cut samples from thin plastic,
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.
7.2 Mounting the Specimen—Affix one end of the web strip
Bridle devices such as the one shown in Fig. 3 allow a straight
to the bridle end of the force transducer; drape the strip over the
pull of the test strip. If lateral slip occurs in a particular test, the
test roller (cylindrical surface), and apply the desired tension-
results will probably be different from a test in which this
ing mass. Avoid clamp systems that have significant elasticity.
unwanted slip does not occur.
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.
and relative humidity. Both friction and temperature at the time
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
7.3 Setting the Sliding Parameters:
be simulated. Test samples should be incubated for an adequate
7.3.1 Velocity—The capstan friction tester allows selection
time to reach equilibrium in the intended test environment prior
of sliding velocity, sliding distance, and free-end tension on the
to testing. Twenty four hours is a minimum incubation period.
strip. It is recommended that values for these parameters be
6.7 Calibration—A suitable system for calibration of the
selected to simulate the system of interest. The sliding velocity
force transducer is to mount the transducer vertically and
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. High speed will cause instability in the
contact of the web with the conforming cylindrical surface.
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/D3108M)
is more appropriate for high sliding velocities.
7.3.2 Sliding Distance—If the goal of this test method is the
FIG. 3 Method for Gripping the Test Strip static coefficient of friction, th
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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 2013) G143 − 03 (Reapproved 2018)
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
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1894 Test Method for Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting
D3108D3108/D3108M Test Method for Coefficient of Friction, Yarn to Solid Material
E8E8/E8M Test Methods for Tension Testing of Metallic Materials
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
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
(Withdrawn 2016)
G163 Guide for Digital Data Acquisition in Wear and Friction Measurements (Withdrawn 2016)
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
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 Nov. 15, 2013June 1, 2018. Published November 2013July 2018. Originally approved in 1996. Last previous edition approved in 20092013 as
G143–03(2009).G143 – 03 (2013). DOI: 10.1520/G0143-03R13.10.1520/G0143-03R18.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G143 − 03 (2018)
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. A third 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.
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
G143 − 03 (2018)
FIG. 1 Schematic of Capstan Friction Test
FIG. 2 Use of Tensile Test Machine to Perform the Capstan Friction Test
data are not valid. Analog strip chart recorders have been shown to be acceptable recording devices for this test method. (See Guide
G163 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
G143 − 03 (2018)
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
simulated involves some special environment, then this should be simulated. Test samples should be incubated for an adequate time
to reach equilibrium in the intended test environment prior to testing. Twenty four hours is a minimum incubation period.
6.7 Calibration—A suitable system for calibration of the force transducer is to mount the transducer vertically and simply apply
a series of known weights on the transducer with the force recording device running. Make sure that the output of the force
transducer is linearly proportional to the applied force over the range of forces to be measured. Calibrate using weights that produce
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 E122 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—The capstan friction tester allows selection of sliding velocity, sliding distance, and free-end tension on the strip.
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.
High speed will cause instability in the contact of the web with the con
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