Protection principles and methods of production when the slide
(1) may generate static electricity to prevent the accumulation of static electricity. To take measures within a safe range.
(2) an existing static build quickly eliminated, immediate release.
Static protection methods:
(1) The use of anti-static material: Metal is a conductor, the conductor of the discharge due to leakage current, will damage the device. In addition, as the insulating material prone to friction electrification, it is not made of metal and insulating material for anti-static material. Instead of using a so-called static surface resistivity conductor l × 105Ω · cm or less, and a surface resistance of 1 × 105-1 × 108Ω · cm of static sub-conductors, as an antistatic material. Such as conventional electrostatic protective material is mixed in the rubber conductive carbon black to achieve the surface resistance control in 1 × 106Ω · cm or less.
(2) leakage and ground: The site may produce or have produced static electricity to ground, provide electrostatic discharge passage. Use of buried earth wire method to establish "independent" ground. So that the resistance between the ground and the earth <10Ω. (See GBJl79 or SJ / T10694-1996) electrostatic protective material grounding method: electrostatic protective material (such as for use as table mats, floor mats, anti-static wrist strap, etc.) through 1MΩ resistor connected to the earth wire leading independent conductor (See SJ / T10630-1995). 1MΩ series resistor is to ensure venting <5mA of current, called the soft ground. Device housing and electrostatic shield is usually connected directly to ground, called Yingjie. IPC-A-610C standard anti-static table recommended grounding method shown in Figure 1.
(3) conductors eliminate static electricity: Static electricity conductor grounding method can be used to make static leakage to earth. BU voltage discharge body and release time can be expressed as: UT = U0L1 / RC where UT-T time voltage (V) U0 a starting voltage (V) R- equivalent resistance (Ω) C- conductor equivalent capacitance (pf) general requirements for the static leakage within one second. Within 1 second will 1OOV voltage drops below the safety zone. This prevents leakage too fast, the leakage current is too large for SSD damage. If U0 = 500V, C = 200pf, want to make UT reached within 1 second 100V, it requires R = 1.28 × 109Ω. Therefore ESD protection systems commonly used 1MΩ limiting resistor, the discharge current is limited to 5mA or less. This is for operating safety design. If the operator in the electrostatic protection system, accidentally touched the 220V industrial voltage, it will not be dangerous.
(4) Non-conductor with static elimination: For static electricity insulator, because the charge can not flow in the insulator, and therefore can not eliminate static electricity by grounding method. You can use the following measures:
(A) use of ion fan - the fan produce positive ions and negative ions can neutralize static sources of static electricity. It may be provided in the vicinity of the space and mounter paste titles.
(B) the use of static elimination agent - static elimination agent belonging surfactant. Available static elimination agent Sassafras wash equipment and the surface can quickly eliminate static object surface.
(C) control humidity - Increased humidity can increase the surface conductivity of non-conductive material, so that the surface is not easy to build up static electricity. For example northern dry environment measures can be taken to the humidifying ventilation.
(D) the use of an electrostatic shield - easy to produce static electricity on equipment can shield (cage) and shield (cage) effectively grounded.
(5) Process Control Act: manufacture of electronic products in order to minimize the generation of static electricity, control static charge buildup of static electricity build-up already exists quickly eliminated, immediate release, regard should plant design, equipment installation, operation and management system take effective measures.
