How to control ESD protections in a PCBA factory?
In the modern electronic industry, it is impossible to generate static electricity under normal conditions, but the generation of static electricity is not a hazard. The real danger lies in the accumulation of static electricity and the resulting electrostatic discharge. Therefore, the control of static electricity accumulation and electrostatic discharge are particularly important. Belows are the protections for controling ESD.
1. Anti-static ESD labeling
All static-sensitive devices are stored and transported in the EPA control area. All static-sensitive devices are tested and monitored for the entire static control process.
2. EPA Control Method
Define the level of protection level, clearly defined and identified. In order to eliminate all unnecessary static electricity generation, all conductors in the area, including personnel, should be reliably grounded and ESD protection system files should be established.
3. Environmental control
The manufacturing and maintenance area is a high-static area with a temperature of 20~30°C and a relative humidity (RH) of 45~75%.
The temperature and humidity of other anti-static work area environment are generally required: temperature is 20~30°C, relative humidity (RH) is 30~75%
Note: When the product material has special requirements on the ambient temperature and humidity, the corresponding local environmental assurance measures should be taken according to the needs and actual conditions.
4. Grounding control
Electrically or electrically connect a conductive part of an electrical device to the earth, called electrical grounding, referred to as grounding. Grounding is usually achieved by contacting the metal grounding body buried in the ground with the soil. The metal conductor or conductor system is artificially buried in the soil to form a metal grounding body called an artificial grounding body. Various metal components, metal well pipes, metal reinforcement pipes for reinforced concrete buildings, metal pipes and equipment for non-combustible materials, etc., which have been buried in the soil, can also be used as metal grounding bodies, which are called natural grounding bodies. The grounding of the electrical equipment is achieved by electrically connecting a conductive portion of the electrical device to the grounding body through the conductor.
5. Anti-static operating desk
The size of the anti-static table mat should not be less than the size of the desk surface; the anti-static mat (anti-static surface) must be facing up and back side (conductive layer) facing down. The grounding wires of multiple anti-static worktables can’t be connected in series. Parallel connection to the common grounding wire, each pad (floor mat) must be connected with only one anti-static ground wire.
6. Anti-static specifications for workshop staff
All personnel must wear anti-static overalls, bracelets, hats, work shoes or shoe covers when entering the anti-static area. Anti-static work clothes should be replaced at designated locations, and work clothes should not be worn or removed near the equipment.
7. Anti-static packaging, storage, and transfer
Anti-static storage temperature is 20~30°C and relative humidity (RH) is 30%~75%.
Note: If there are special requirements for the environment, such as moisture sensitive devices, please follow the corresponding special operation instructions.
Storage device: It can be used to directly store static sensitive devices and components. It has anti-static device box, IC tube, anti-static bag, anti-static turnover box, single-board turnover car, etc.
8. Anti-static packaging, storage, transfer storage operation guidelines
(1) Electrostatic sensitive devices must be stored in anti-static device boxes, shielding bags, and anti-static devices. Electrostatic sensitive boards and components should be stored in shielding bags, anti-static plastic boxes, turnover boxes, and revolving carts.
(2) Electrostatic sensitive devices should be kept in the original packaging state as much as possible. It is forbidden to unpack them at will.
(3) Operating desk for electrostatic sensitive devices for bulk counting and dispensing must be equipped with an anti-static mat and grounded reliably. The operator should wear anti-static gloves, finger cots or a corded anti-static wrist strap into the anti-static grounding system.
(4) During the storage and transportation process, do not approach strong static electricity or strong electromagnetic fields, such as the computer main unit and its display, and the sides of the public pedestrian channel.
9.Management and maintenance of anti-static area
(1) Develop an anti-static management system and have a dedicated team or personnel.
(2) Spare anti-static overalls, shoes, bracelets and other items for use by outsiders.
(3) Regularly maintain and check the effectiveness of anti-static equipment.
(4) The anti-static wrist strap must be inspected once a day before use.
(5) The grounding of the table mat and floor mat and the performance of the static eliminator are checked once a month.
(6) The anti-static performance of anti-static component frame, printed board frame, turnover box, transport vehicle, table mat and floor mat is checked once a month, and the damaged equipment should be replaced in time.
