Protection in electrostatic production
1. The main process links in production
Main process steps in the production process of electronic products, electrostatic sensitive devices entering the factory for inspection, sophisticated screening and testing - support, inventory and storage - acceptance of ingredients - receiving, sending, receiving, returning materials - pre-processing (including pre- Processing) - PCB mounting, plugging, welding - unipolar debugging - PCB loading machine - trial operation, observation (including high temperature training) - inspection - pre-packaging - intermediate processing - finished product input library , turnover, temporary storage, etc.
2. Establish the process principle of electrostatic protection zone (point)
(1) According to the electrostatic sensitivity of the devices used in this operation area, it is divided into the first level, the second level and the third level, and different protection measures are formulated according to different levels.
(2) According to the humidity of the area where the manufacturer is located, refer to the annual average humidity, season, monthly average humidity and minimum humidity range, and take the corresponding effective protection process according to the conditions below the average humidity. When determining the protective measures, it is especially important to note that the electrostatic high voltage that may be generated by the minimum humidity is harmful to the sensitive device.
(3) According to the actual measured static voltage data in the operating environment where the factory protection zone (point) is located, the protection level is more appropriate.
(4) All protective methods and measures selected by the electrostatic protection zone (point) should be of a small variety, with the lowest cost and sufficient effect to meet the protection requirements.
3. General requirements for electrostatic protection areas
(1) There are at most two entrances and exits in an ESD zone and are considered as safety gates in a prominent position at their doorways. A permanent safety zone nameplate with a yellow-black sunspot and a permanent uniform warning sign.
(2) The room temperature of the working area should be controlled between 15-20 °C, and the relative humidity should be controlled between 50-70%.
(3) Instantaneous high-voltage sources or timely high-pressure operation should be avoided in the ESD protection zone.
(4) The desktop, instruments, and human body must be safely grounded (ie, at zero potential). Electrostatic desktops must not be covered with ordinary plastic plates, plastic sheets, rubber boards, rubber pads, etc.
(5) It is forbidden to place non-productive items such as tableware and other items on the workbench.
(6) The drawings and materials used by the operator should be placed in a transparent anti-static plastic bag.
(7) Operators should wear anti-static overalls, anti-static work shoes (socks), anti-static work gloves and work caps.
(8) Non-protection area personnel, when they enter the production site with permission, they also wear anti-static overalls, work shoes, and do not touch the SSD or PCB at the production site, and are not allowed to be close to the person who is operating.
(9) The electrostatic protection zone should be avoided in the vicinity of the electromagnetic field of the high-power radiation source.
(10) The facilities in the ESD area shall be installed in accordance with the static control methods and process regulations determined by the production process.