ASTM G143 is a standardized test method used to evaluate the friction behavior between a flexible web material and a cylindrical roller surface. The method measures both the static and kinetic coefficient of friction (COF) during sliding contact and helps manufacturers understand how web materials interact with rollers in converting, printing, packaging, coating, laminating, and other continuous web-processing operations.
Unlike conventional flat-surface friction tests, ASTM G143 focuses specifically on roller/web friction measurement, simulating real production conditions where films, paper, foils, textiles, and other flexible materials travel across rollers. The resulting friction data can be used for process optimization, material development, equipment design, and quality control.
In many manufacturing processes, flexible materials are transported through a series of driven and idler rollers. The friction characteristics between the web and roller directly influence machine performance.
If friction is too low:
If friction is too high:
By performing an ASTM G143 coefficient of friction test, manufacturers can quantify roller/web interaction and make informed decisions regarding material selection, roller coatings, lubricants, and process parameters.
The test determines:
| Parameter | Description |
|---|---|
| Static Coefficient of Friction (Static COF) | Resistance to the initiation of sliding |
| Kinetic Coefficient of Friction (Dynamic COF) | Resistance during continuous sliding |
| Friction Force | Force required to move the web over the roller |
| Roller/Web Interaction Characteristics | Overall friction behavior under simulated operating conditions |
These measurements provide valuable information for:
The cof test method of roller web systems is based on the capstan friction principle.
A narrow strip of web material is wrapped around a stationary cylindrical roller at a specified wrap angle. One end of the specimen is attached to a force-measuring device while a known tension is applied to the opposite end.
As the specimen slides across the roller surface, the force required to overcome friction is continuously measured. The static and kinetic coefficients of friction are then calculated from the measured tension values.
The calculation is based on the capstan equation:
μ =
ln(T2/T1)
θ
Where:
This approach enables realistic simulation of web transport systems commonly used in industrial production environments.
Proper specimen preparation is essential for reliable results.
Typical specimen dimensions include:
| Parameter | Typical Value |
|---|---|
| Width | 25 mm |
| Length | 500 mm |
| Minimum Replicates | 3 |
Important considerations:
The specimen is mounted by:
Correct mounting minimizes testing variability and improves repeatability.
ASTM G143 recommends selecting velocities that simulate the actual application.
Typical testing velocities range from:
Velocity selection should reflect real operating conditions whenever possible.
For static COF determination:
For static and kinetic COF determination:
ASTM interlaboratory studies commonly used:
Web tension should represent actual process conditions.
Typical testing may involve:
The wrap angle significantly affects friction calculations.
Common values include:
| Wrap Angle | Application |
|---|---|
| 90° | Recommended by ASTM G143 |
| 180° | Maximum allowed |
| Custom Angles | Process simulation |
A 90° wrap angle is widely used because it balances practicality and repeatability.
Many users compare ASTM G143 with ASTM D1894.
| Feature | ASTM G143 | ASTM D1894 |
|---|---|---|
| Contact Geometry | Roller-Web | Flat Surface |
| Primary Application | Web Transport Systems | General Material Friction |
| Friction Model | Capstan-Based | Sled-Based |
| Process Simulation | High | Moderate |
| Packaging Film Evaluation | Excellent | Commonly Used |
ASTM D1894 remains the most widely used packaging-film COF method, while ASTM G143 provides a more realistic simulation of roller-driven production environments.
Performing ASTM G143 testing requires:
Many laboratories use a universal tensile testing platform equipped with custom friction fixtures to perform roller/web friction measurement.
The TST-01 Tensile Tester can serve as the core platform for ASTM G143 testing when combined with a customized roller/web friction fixture.
Key advantages include:
For laboratories evaluating multiple materials and friction conditions, customized fixtures and multi-station solutions can further improve testing efficiency and repeatability.
Understanding roller/web friction characteristics is essential for ensuring stable web handling, efficient manufacturing, and consistent product quality. ASTM G143 provides valuable data for evaluating materials, roller surfaces, coatings, and processing conditions. Cell Instruments offers tensile testing platforms, customized friction fixtures, and application-specific testing solutions designed to support ASTM G143 and other coefficient of friction testing requirements. Whether you are developing new materials or improving production performance, selecting the appropriate testing system can help generate reliable and actionable friction data.
When precise and standardized measurements are needed, our Coefficient of Friction Testing Solutions provide a versatile.
Mastering COF testing is not just a technical necessity—it’s a competitive advantage.
Discover how our Coefficient of Friction Tester can optimize your plastic film performance—contact Coefficientfriction.com today for expert solutions!
Contact info: marketing@celtec.cn
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