Commonly used anti-static products
⒊Anti-static wrist strap and foot strap
Anyone who handles ESDS devices should use anti-static wrist straps and foot straps. The role of wrist straps and foot straps is to quickly leak the static charge of the human body to the ground.
A general anti-static wrist strap is composed of a buckle, a belt, and a ground connection wire. The straps, buckles and ground connection wires have good electrical contact. In order to ensure the safety of operators, there is usually a 1 megohm resistor in series on the ground connection line of the wrist strap to limit the current flowing through when the human body is shocked by the ECG to no more than 5 mA.
When using the wrist strap, make sure that the wrist strap is in good contact with the human wrist, the ground connection wire, and the ground wire. The foot straps and anti-static shoes have the same function, so I won't introduce them.
⒋Protective finger cots
The finger cots used by people who operate ESDS devices are made of latex with antistatic agents to prevent ESDS devices from being damaged due to unequal potentials. The surface and volume resistance of the finger cot should be lower than 1*10, which is 9 ohms.
⒌Anti-static socks
Anti-static socks are prepared by implanting mintu silk into the sole material to achieve electrical contact between the human body and conductive shoes. The resistance of the bottom of the socks should not be greater than 8 ohms of 1*10.
⒍Work hat
The hat material is the same as the work clothes. It is not only used for anti-static, but also has the function of preventing dust and hair from falling on the ESDS device of the operator's head.
⒎Anti-static packaging (bags, turnover boxes, trays, boxes, foam fillings, foam materials)
There are many kinds of anti-static packaging, there are more than 20 kinds. Most of them are made of anti-static modified polymer materials, such as polyethylene (PE) ABS, FRP, polypropylene (PP) and so on.
Anti-static packaging must be used for storage and transportation of electrostatic sensitive devices. The anti-static package provides equipotential effect on the ESDS device and has the effect of leaking and dissipating static electricity on the insulating surface of the DSDS device. The electrostatic shielding packaging material provides shielding to electrostatic induction to protect the ESDS device. The use of packaging materials should be non-corrosive, toxic and dust-proof.
⒏Running car, storage rack, conveyor belt
The structure of the moving vehicle and the storage rack is a metal frame. The table top is made of static dissipative material and has a good electrical connection with the metal frame. The trolley is weak and the storage rack feet are made of conductive rubber. The transmission belt is made of anti-static rubber and connected to the grounding device. These equipment are used for static dissipation and leakage.
⒐Working table, work chair
The work surface is made of static dissipative material and connected to the ground wire of the workbench. Static electricity generated by the friction of the work surface can leak from the ground wire. The surface of the work chair is static dissipative material. The structure of the chair is metal, and the casters are anti-static casters and the earth forms a static leakage path.
⒑Anti-static floor
The ground of the anti-static work area should have static dissipation performance, so it is also called an anti-static floor. There are carpets, rubber, PVC floor blocks, epoxy resin, raised raised floors (wood, steel, aluminum) and cement. The main function of the anti-static floor is to dissipate the static electricity of the human body and anti-static equipment. The ground is generally set up with a grounding network and connected to the anti-static ground.
⒒Anti-static tools
Anti-static electric soldering iron: There are two types of soldering iron head and shell connected with the ground wire and low voltage (DC36V, 48V, etc.) constant temperature. Used to prevent the soldering iron tip and the shell from damaging the ESDS device due to induction charging or leakage.
Tin suction device: the suction head is connected to the ground wire to prevent induction and electrification
Maintenance tools: there are pliers, tweezers, clamps, scissors, screw cutters, wire clamps, shunt bars, etc. Made of non-ferromagnetic static dissipative materials, used for chest power dissipation and prevention of static discharge.
⒓Anti-static grounding
In order for the anti-static system to work, an anti-static ground must be installed in the anti-static work area. In general, the anti-static grounding should be connected with the following anti-static equipment and equipment: anti-static floor; workbench; storage rack, wrist strap; wave soldering machine; microelectronic assembly equipment; spray cleaning paint sandblasting equipment; welding equipment ; Wet box; High-voltage equipment; Special test equipment.
⒔Environmental control system
In the anti-static work area, there should be environmental humidity and humidity control equipment, so that the environmental humidity is controlled at about 20-25 degrees, and the humidity is about 50%-75% to prevent excessive explosion and low humidity from causing obvious static electricity. In addition, the production and assembly workshops of ESDS devices with special requirements should be equipped with air showers and air purification systems to make the production environment reach the corresponding purification level.
⒕Special production equipment
Electrostatic grounding or electrostatic shielding measures must be taken for inserting, patching, welding, assembling, testing, and certain high-voltage power supply enclosures and parts that contact ESDS devices.
⒖Ionization static eliminator (ionizer)
Where cross-grounding is not possible, ionized air can be used to discharge static charges, or to dissipate static charges on insulators that cannot be effectively grounded. Ionizers are also useful for dissipating charges where processes like sandblasting and spraying have been performed. The three methods commonly used to ionize air are radioactive, electric, and electrostatic combs. Radioactive materials provide particles that ionize the air. The electrical method uses a high-voltage square wave signal to ionize the air. The principle of an electrostatic comb is similar to that of a lightning rod. It uses the concentrated charge on the tip of the needle to ionize the air. This method is based on the principle that the barrel repels itself according to the charge from the aspheric body, so that the charge is deposited on the surface with the smallest radius of curvature. The air from the ionizer should contain approximately equal orders of positive and negative ions. The imbalance of positive and negative ions can cause residual voltage across the ionized area. The placement of the ionizer should be determined according to the manufacturer’s recommendations or through experience. The manufacturer's specifications usually provide information on the relationship between the decay time and the distance and angle between the ionizer and the charged area. It may take a few seconds or even minutes for the ionizer to dissipate the charge, depending on the amount of charge and the distance of the charge from the source. In order to neutralize the charge on the charged area, the ionizer should work for at least 2 to 3 minutes. Some ionizers have extremely high residual voltage, which can damage some ESDS products. In order to properly control ESD, when selecting and placing the ionizer, it is necessary to measure the residual voltage on the protected product, and compare it with the voltage of the first-made ESDS product and the voltage sensitivity level of the first-made ESDS product. Compare.
From an occupational health point of view, certain ionizers generate high voltages, which can cause dangerous electric shocks to people. In addition, the ozone produced by the ionizer can also have an unfavorable effect on people. Therefore, the ozone concentration should be limited to the relevant national standards when designing ionizers.