To test fabric flat abrasion, you can follow these steps:

1. Prepare the necessary materials: You will need a testing machine or an abrasion tester, a rubbing fabric or abrasive material, and the fabric sample you want to test.

2. Cut the fabric sample: Cut a rectangular piece of fabric that is representative of the material you want to test. Make sure it is large enough to fit into the testing machine.

3. Set up the testing machine: If you are using an abrasion tester, follow the manufacturer's instructions to set it up properly. Ensure that the machine is calibrated and functioning correctly.

4. Secure the fabric sample: Attach the fabric sample to the testing machine, making sure it is taut and flat.

5. Choose the rubbing fabric or abrasive material: Depending on the specific test requirements, select the appropriate rubbing fabric or abrasive material. Commonly used materials include cotton or felt fabric, emery cloth, or sandpaper. The choice will depend on the intended application of the fabric being tested.

6. Conduct the test: Start the testing machine to initiate the rubbing or abrasion process. The rubbing fabric or abrasive material will move back and forth across the fabric sample, simulating wear and tear.

7. Monitor and record the results: Observe the fabric sample during the testing process to note any visible changes or damage. Record the number of cycles or time duration until a predetermined endpoint (e.g., fabric failure, noticeable wear, or loss of color) is reached.

8. Evaluate the results: After the test is completed, analyze the fabric sample for signs of abrasion, such as fraying, pilling, or color fading. Compare the results with established standards or specifications to assess the fabric's durability and abrasion resistance.

It's worth noting that specific test procedures may vary depending on the testing equipment and standards used. Therefore, ensure you follow any guidelines provided by the manufacturer or applicable industry standards when conducting fabric flat abrasion test.