Anti-static performance testing of clean and dust-free clothing
In areas with high anti-static requirements, the anti-static performance of the anti-static dust-free gown worn by workers in the clean room is also very important. For example, in the microelectronics industry, static electricity can damage tiny circuits. When people move in a clean room, their clean clothes will rub against the anti-static work clothes and skin worn inside the seats, workbenches, and generate static electricity in the clothes. This static electricity will be released to the integrated circuit and destroy it. In the production of clean clothing fabrics, continuous wires made of conductive materials are woven in the fabrics. When choosing clothing with low electrostatic discharge*, the following tests can be carried out:
Measuring resistivity or conductivity;
Measure the attenuation of the voltage;
Measure the voltage generated when the personnel wear anti-static clean clothes while moving.
There are several methods for testing the surface resistivity of fabrics. The lower the resistance, the better the fabric, because the lower the resistivity, the easier it is for static electricity to be conducted away.
Another way to measure the antistatic properties of a fabric is to observe the decay time of static electricity on the fabric. This method is better than measuring conductivity. First, a charge with a known voltage is generated on the fabric, and then the time required for the voltage to drop to 1/2 or 1/10 of its original value is measured. The time can vary from less than 0.1 seconds to more than 10 minutes. The shorter the time, the better the antistatic effect of the fabric.
A person stood up from a chair wearing clothes made of two anti-static fabrics, and then measured the voltage of his body. When the person and chair are insulated from the ground, the maximum voltage for non-wire clothing is 3210 volts, and the maximum voltage for clothing with wires is 2500 volts.
The difference between the two is not obvious. But if the chair is grounded and the personnel wear conductive shoes, the result will be much better.
These results illustrate how important it is to ground chairs, personnel, and clothing, and also the importance of choosing appropriate anti-static clothing.