Testing the strength of a zipper usually requires the use of a tensile testing machine. Here's a simple step:

1. Prepare the test sample: fix the zipper on the test jig, make sure that the contact area between the jig and the zipper is as large as possible to avoid slipping or twisting during the test.

2. Set test parameters: Set the parameters of the tensile testing machine according to the test requirements, such as test speed, test range, etc. Typically, the test speed is between 50 mm and 500 mm per minute.

3. Start the test: Start the tensile testing machine and allow it to apply increasing tension until the zipper breaks. During the test, it is necessary to observe the deformation of the zipper and the stability of the test fixture.

4. Record the test results: After the test is completed, record the maximum tension value when the zipper breaks and the tension-displacement curve during the test. According to the test results, the strength and durability of the zipper can be evaluated.

It should be noted that when testing the strength of zippers, the way of testing speed and force is also important. Test speed should be standardized to ensure comparability of test results. In addition, the sample should be prevented from being distorted or otherwise disturbed during the test to ensure the accuracy and repeatability of the test results.

In addition, in order to more comprehensively evaluate the performance of the zipper, some other tests can also be carried out, such as the wear resistance, corrosion resistance and oxidation resistance of the zipper. These tests can be done with different test instruments and methods.