Pin on Disk Sliding Wear

 Using the Micro-Tribometer mod. UMT with Rotational Motion Drive

ASTM G99-95

Test method for determining the wear of materials during sliding using the UMT in a pin-on-disk configuration.

Summary of Test Method:

This test method involves a ball shaped upper specimen that slides against a rotating disk as a lower specimen under a prescribed set of conditions. The load is applied vertically downward with a motor driven carriage that uses the force/load sensor for feedback to maintain a constant load.

The UMT allows for monitoring during the test the actual dynamic normal load, friction force and friction coefficient, and depth of wear. Optionally, it can measure additional parameters of contact acoustic emission, electrical contact resistance, and temperature.

ASTM G99-95 does not specify test parameters such as rpm, load, or test duration. The configuration below is an example of one of many possible combinations of friction/load sensor, rotational drive, specimen holder, and specimens.

UMT Hardware Configuration:

·         4” Mounting Block – PN M30C116

·         Model DFH-2 Dual Friction/Load Sensor

-          range 0.2 N to 20 N

·         Suspension with Linear Guide-AM30C110D-1

·         3/8” Ball Holder –AM30B310B

                  -    for sensors mod. DFH

·         440-C Stainless Steel Ball, Dia. 3/8”- PN BM110006

·         Stainless Steel Disk

·         Medium Torque Rotation Drive

-    Mod. SHHM

·         Optional Additional Sensors

 - mod AE-5 Acoustic Emissions Sensor

 - mod ECR-xx Electrical Contact Resistance

 - 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 Medium Torque Rotational Motion Drive and the 20 N force/load sensor.

Use the Semi-Automatic Mode to pre-position the x-axis slider so that the ball is 16 mm from the center of rotation of the lower specimen. This will create a circular wear track with a diameter of 32 mm.

Test Sequence:

The Test Sequence should consist of 2 sheets.

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

     Carriage - applies a 10 N Constant Force for a Duration of 10 sec.

     Spindle  – Velocity is 0 revs/min.

     Slider     – is idle.

Sheet 2 is a 16 min. 40 sec. period

     Carriage - applies a 10 N Constant Force for a Duration of 10000 seconds.

     Spindle   – Velocity is 60 revs/min, Move-Continuous,  and Direction- Clockwise

     Slider      – is idle.

Data Collection:

The following should be checked under DataFile:

    Fx – Friction Force

    Fz – Normal Force

    T   – Time

    Z1 – Carriage Position (Used to determine Wear Depth)

    Te - input – Temperature (optional)

    AE – Acoustic Emission (optional)

    EC – Electrical Contact Resistance

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.