Standard Test Method for Ranking Resistance of Plastic Materials to Sliding Wear in a Block-on-Ring Configuration Using Micro-Tribometer mod. UMT-2

ASTM G137-97

 

 

Summary of Test Method:

 

This test measures the wear resistance of plastic materials under dry sliding conditions in a block-on-ring geometry. A stationary block specimen is pressed with a constant force against a rotating ring specimen at 90Ί to the ring’s axis of rotation. Friction between the sliding surfaces of the block and ring results in loss of material from both pieces. The test may be run at various loads, velocities, and temperatures which simulate the service conditions. The standard  lists typical parameters:

Ring dimensions – 100mm dia. x 15.88 mm width

Block dimensions – 6.35 mm x 6.00 mm x 12.7 mm

Normal load range – 20 to 40 N

Velocity range – 0.5 to 1 m/s

 

The standard recommends to measure weight loss for wear characterization. The test should be interrupted a minimum of 6 times to weigh the block specimen to determine the mass loss as a function of time. The test should be continued until 3 or more measurement indicate a steady state rate of change. The UMT-2 can additionally measure in-situ (during the test) dynamic wear depth, friction force and coefficient. This is both more accurate and repeatable (due to the elimination of misalignment  every time the test restarts) and less laborious (due to the elimination weight measurements). Once the wearing surface on the block conforms to the curvature of the ring the in-situ wear depth plot closely corresponds to the mass loss rate.

 

UMT Hardware Configuration:

 

·         4” Mounting Block – PN M30C116

·         Model DFH-5 Dual Friction/Load Sensor

-   range 0.5 to 50N

·         Suspension for Dual Sensor with Linear Guides

-   PN AM30C110D-1

·         Upper Specimen Block Holder for sensors mod. DFH

-          PN M30D059

·         Plastic Block  Specimen 6.35 mm x 6.00 mm x 12.7 mm

·         Ring – 100mm dia. by 15.88 mm width

·         Block-on-Ring Drive

-    mod. BHHM

·         Optional Additional Sensors

-    mod. AE-5 Contact Acoustic Emission Detector

       -    mod. TMR-150 Temperature Measurement & Recording

       -   mod. RTD Temperature Sensor

 

 

 

UMT Software Test Setup:

 

UMT Options File:

Load the options file which contains settings for the block-on-ring drive and the 50N force/load sensor.

 

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 30N Constant Force for a Duration of 10 sec.

     Spindle  – Velocity is 0 revs/min.

     Slider     – is idle.

Sheet 2 is the wear-resistance test period

     Carriage - applies a 30N Constant Force for a Duration of 30 minutes.

     Spindle   – Velocity is 191 revs/min, Move- Continuous,, and Direction-Counter-clockwise.

     Slider       – is idle.

The block specimen is weighed after each test. The Duration in sheet 2 can be lengthened in successive tests.

 

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)

    AE input – Acoustic Emission (optional)

    Te input – Temperature (optional)

 

Report:

 

Use the Viewer program to plot test results.

Select the parameters to be displayed by checking

the appropriate box under Parameters on the Viewer screen.