Why anti-static
We all know that the main form of electrostatic hazards in the electronics industry is sudden failures and potential failures of components caused by electrostatic discharge, which in turn causes the performance of the entire machine to decline or fail. Therefore, the main purpose of antistatic and controlling static electricity should be to control electrostatic discharge, that is, to prevent the occurrence of electrostatic discharge or reduce the energy of electrostatic discharge below the damage threshold of all sensitive devices. In principle, antistatic should be carried out from two aspects: controlling the generation of static electricity and controlling the dissipation of static electricity. Controlling the generation of static electricity is mainly to control the process and the choice of materials during the process; controlling the dissipation of static electricity is to quickly and safely discharge the static electricity Discharge and neutralization; the combined effect of the two may make the static level not exceed the safety limit and achieve the purpose of anti-static.
When an object has a certain amount of net positive charge or net negative charge, it can be said to have static electricity. Static electricity is a relative term because, in many cases, static electricity gradually decreases over time. The length of this period is related to the resistance of the object. Two extreme examples of practical applications are plastics and metals.
In general, the electrical resistance of plastic is very high, so plastic can remain static for a long time. The resistance of the metal is very low, and the grounded metal is extremely short of static electricity. Static electricity is usually expressed in volts. Although 220 volt AC power is dangerous, 100kV static electricity is quite common. The voltage in an object is determined by two factors: the charge of the object and the capacitance of the object. It can be expressed by a simple relationship, that is, Q = CV, where Q represents the amount of electricity, V represents the voltage, and C represents the capacitance of the object.
Given the charge of an object, the lower the capacitance, the higher the voltage, and vice versa. Plastics generally have very low capacitance, so very little electricity can generate high voltages. In contrast, the capacitance of metal is very high, so more electricity generates only a lower voltage. This is why in practice, the issue of static electricity caused by the use of plastics is more important. High voltages can attract dust, cause an electric shock to the operator, or cause a change in object properties.
There are two main types of static electricity: bulk static electricity and surface static electricity. Bulk static refers to the electric charge distributed inside an object. Surface charge refers to the charge on the outermost surface of an object.