When using anti-static dust-free clothing, what is the normal static voltage?
After we bought the anti-static dust-free clothing, we can't just listen to the supplier saying that anti-static is enough. If you have any questions, you may wish to learn more about how it is tested for anti-static performance. I will introduce it to you below. The following test methods are for reference only.
Electrostatic performance is an important indicator to evaluate the quality of work clothes. The general electrostatic test has four parts: friction voltage test, electrostatic voltage test, resistance test, decay time test.
1. Voltage test
This test is mainly to verify whether the cloth itself can reach a specified stable value in a short period of time after accumulating some voltage through friction, which is mainly to test the quality of the conductive wire.
Test method: On a dedicated ESD test bench (grounded), the tester rubs the surface of the cloth several times (usually 5-10 times) with a certain strength and speed, and then uses the probes of the dedicated voltage tester to separate 5cm Align the rubbed part left and right, and read the voltage value after 5 seconds.
Test standards, the requirements of ESD for clothing in the semiconductor industry generally require less than 100V. Some industries have stricter standards, such as wafer and magnetic head industries, and 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 away through the conductive wire after accumulating a certain amount of static electricity in the environment and how much it stays.
The test method is to place the clothes to be tested on a special test bench, and use the probes of the electrostatic tester to read the voltage value at a distance of about 5CM.
The test standard is determined according to the design standard of the customer's work clothes, and the most stringent can be required to be less than 5V. Generally around 50V is more common.
3. Resistance test
This test can verify the conductive efficacy 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. Usually, different points of the work clothes need to be tested, such as between a piece of fabric, between different fabric blocks, sleeves and sleeves. Between pants, pants to pants, etc.
Test standards, according to the standards of the semiconductor industry, most companies control the resistance of work clothes at 105-109 ohms, and some are strictly set at 105-107 ohms.
4. Decay time
This test is mainly to verify how long the conductive wire of the fabric can dissipate the high voltage to a certain range after being applied with high voltage.
The decay time of most fabrics can be less than 0.5 seconds, and the specific requirements are determined by different anti-static customers.