Standard Test for Measurement of Web/Roller Friction Characteristics

Using the Micro-Tribometer mod. UMT-2

ASTM G143-96

Summary of Test Method:

This 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. In the hardware configuration below one end of a strip of the web material is attached to the friction force/load sensor. Then it is wrapped under the roller specimen on the block-on-ring drive. The strip is then draped over a freewheeling pulley, and a tensioning weight is hung from its free end. The test can be operated in two ways prescribed in the standard. One method is to keep the roller specimen stationary, while moving the z carriage up and down. This continuously changes the contact area of the web, while the contact area of the roller remains the same. The sliding distance can be up to 150 mm, and the velocity can be up to 10 mm/s. The second method is to keep the z carriage stationary, while rotating the roller with the block-on-ring drive. The contact area of the web is constant, while the contact area of the roller is its entire circumference. The roller can spin from 0.1 to 5000 rpm. The static and kinetic coefficient of friction calculations are done per the standard.

The UMT can measure additional parameters of contact acoustic emission and temperature with optional sensors. Extended tests can determine wear resistance.

The standard does not specify test parameters such as speed, load, or test duration, but recommends that the sliding velocity between the web and the roller should not exceed 10% of the velocity of the web transport being simulated.

UMT Hardware Configuration:

· 1” Y-direction Manual Positioning Stage – PN BM290012

· Model DFM-0.5 Dual Friction/Load Sensor

- range 0.05 N to 5 N

· Block on Ring Drive

- Mod. BHHM

· Roller Lower Specimen

· Web Material

· Free Wheeling Pulley Attachment

· 1 kg Tensioning Weight

· Optional Additional Sensors

- mod AE-5 Acoustic Emissions Sensor

- mod. TMR-150 Temperature Measurement & Recording

- mod. RTD Temperature Sensor

UMT Software Test Setup:

UMT Options File:

Load the options file that contains settings for the Block-on-Ring Drive and the 5 N force/load sensor with Fz Reversed.

Test Sequence:

Use the Semi-Automatic Mode to move the carriage to its upper limit and set the carriage position to zero. Move the carriage to its lowest position and attach the web and tensioning weight. Position the x-axis stage so that the web is perpendicular between the sensor and the roller. Adjust the y-axis stage to center the web on the roller. Move the carriage to its upper limit and set the carriage position to zero. The following test sequence slides the web against the roller for 150 mm at 5 mm/s.

Sequence

Engage – Force 0.9N, Z-Carriage Velocity Pretouch 0.1, Touch 0.05, Near 0.02

Test – Tolerance Positive 0.5, Negative 0.5

Sheet 1 is for settling time for the carriage to establish the initial normal load.

Carriage - applies a 1 N Constant Force for a Duration of 5 sec.

Spindle – Move Continuous Velocity is 0 revs/min.

Slider – is idle.

Sheet 2 is a 30 sec. period

Carriage – Absolute Carriage Displacement from 150mm to 0mm for a Duration of 30 seconds, Velocities - working 5 mm/s, Initial 1 mm/s.

Spindle – Move Continuous Velocity is 0 revs/min.

Slider – is idle.

Data Collection:

The following should be checked under DataFile:

Fz – Normal Force

T – Time

Z1 – Carriage Position (sliding distance)

Te input – Temperature (optional)

AE – Acoustic Emission (optional)

Report:

Use the Viewer program to plot test results.

Select the parameters to be displayed by checking

the appropriate boxes under Parameters on the Viewer screen.

Subtract the 1 N weight to get friction values.