Use anti-static dust-free clothing, what is the normal electrostatic voltage?
After we bought the anti-static dust-free clothing, we can’t just listen to the supplier saying that it can be anti-static. If you have any questions, you may wish to learn more about how it is tested for anti-static performance. Let me introduce you The following test methods are for reference only.
Electrostatic performance is an important indicator for evaluating the quality of work clothes. General electrostatic test has four parts: friction voltage test, static voltage test, resistance test, decay time test.
1. Voltage test
The test is mainly to verify whether the fabric itself can reach a specified stable value in a short period of time after it has accumulated some voltage through friction. This is mainly to check the quality of the conductive yarn.
Test method: On a dedicated ESD test bench (grounded), the tester uses a certain force and speed to rub the surface of the cloth several times (usually 5-10 times), and then use the probe of the dedicated voltage tester to be spaced 5cm apart Align the rubbed part left and right, and read the voltage value after 5 seconds.
Test standards, the ESD requirements of clothing in the semiconductor industry generally require less than 100V. Some industries have more stringent standards, such as wafer and magnetic head industries, where the friction voltage is generally less than 20V.
2. Static voltage test
This test is to verify how much the cloth itself can be guided by the conductive wire and how much it can stay after it has accumulated a certain amount of static electricity in the environment.
The test method is to put the clothes under test on a special test bench, and use the probe of the electrostatic tester to read the voltage value about 5cm apart.
The test standard is determined according to the design standard of the customer's work clothes. The most stringent one can be required to be less than 5V. Generally around 50V is more common.
3. Resistance test
This test can verify the conductive effect of the conductive wire and whether the stitching process before the cloth and the cloth meets the requirements, such as the connection between the conductive wires.
The test method is to place the tested work clothes on a special test bench and use a resistance tester to test them. It is usually necessary to test different points of the work clothes, such as between a piece of cloth, between different pieces of cloth, sleeves and sleeves. Between, between pants and pants, etc.
According to the standards of the semiconductor industry, most companies control the resistance of work clothes at 105-109 ohms, and some strictly set it at 105-107.
4. Decay time
This test is mainly to verify how long the conductive thread of the cloth can dissipate the high voltage to a certain range after applying the high voltage.
The decay time of most fabrics can reach less than 0.5 seconds, and the specific requirements are determined by different anti-static customers.