The anti-static equipment used in the production process of PCBA processing can be categorized as human electrostatic protection system, anti-static flooring, anti-static operating system and special supplies.
Human electrostatic protection system includes anti-static wristbands, workwear footwear, hats, gloves, etc. This overall protection system has both electrostatic leakage and shielding functions, and all anti-static supplies should usually be purchased in professional factories or stores.
Direct contact with electrostatic sensitive devices should wear anti-static wristbands, wristbands should have good contact with human skin, wristbands must be no irritation to the human body, no allergic effects, wristband system to ground resistance value should be in the range of 106 ~ 108Ω.
Anti-static table mat should have no less than two wristbands connector, one for the operator, the other for the technical staff inspection personnel or other personnel use.
Enter the anti-static work area or contact with SSD personnel should wear anti-static work clothes, anti-static work clothes fabric should comply with the provisions of GB12014-2009. In an environment where the relative humidity is greater than 50%, anti-static work clothes are allowed to choose cotton products.
Anti-static flooring is to effectively discharge human electrostatic through the ground to the earth as soon as possible, especially because of mobile operations and should not use wristbands of human electrostatic. At the same time, it can also discharge the static electricity on the equipment and work equipment. Ground anti-static performance parameters to determine both to ensure that in a relatively short period of time the electrostatic voltage down to below 100V, but also to ensure the safety of personnel, the system resistance should be controlled between 105 ~ 108Ω.
The materials commonly used in anti-static flooring are as follows:
Anti-static rubber flooring: simple construction, excellent anti-static performance, but easy to wear.
PVC anti-static plastic flooring: anti-static effect is good, high lasting strength, widely used.
Anti-static carpet: anti-static effect is good, easy to use, but the cost is high.
Anti-static movable flooring:Good anti-static effect, beautiful, and extremely high cost.
Allow the use of terrazzo ground by special treatment, such as the prior laying of ground wire network, carburizing or spraying antistatic agent on the ground, etc. Anti-static terrazzo floor has long life, low cost, and is suitable for new plants.
Anti-static operating system refers to the work surface, production line body, tools, packaging bags, storage carts and cleaning liquids, etc. where each process will often have contact, separation or frictional effects with components and finished components. As the materials used in the above operating systems are highly insulating rubber, plastic, fabric and wood, they are very easy to generate static electricity in the production process, so they should be treated with anti-static, i.e. the operating system should have anti-static function.
Anti-static operating systems include:
Anti-static table mat. The operating table are equipped with anti-static mats, surface resistance between 105 ~ 109Ω, and through the 1MΩ resistance and ground connection, turnover boxes, boxes and all other containers should be made of anti-static materials, and labeled with signs.
Anti-static packaging bags. All plastic bags for packaging circuit boards or devices should be anti-static bags. Surface resistance of 105 ~ 109Ω, in the circuit board into or out of the bag, the hands should wear anti-static wristbands.
Anti-static logistics car. Used to transport devices, components of special logistics vehicles, should have anti-static function, especially the logistics vehicle rubber wheels, should use anti-static rubber wheels, the surface resistance of 105 ~ 109Ω.
Anti-static tools. In particular, electric soldering iron, soldering gun, etc. should have anti-static function, usually electric soldering iron should be operated at low voltage (24/36V), the soldering iron head should be well grounded.
In short, all objects in contact with the circuit board or device, including high-speed movement of space, should have anti-static measures. Especially SMT high-speed placement process, the high-speed operation of the device will lead to the rise of static electricity, electrostatic sensitive devices will have an impact.
