May 20, 2023 
1. Anti-static facilities in the SMT patch production line
① ESD protection during SMT processing patch production line should have an independent ground wire and be separated from the lightning protection wire; the ground wire should be reliable and have a complete static leakage system;
② The workshop maintains a constant temperature and humidity environment. Generally, the temperature is controlled at 25°C ± 2°C, and the humidity is 65%±5%RH. The entrance is equipped with ion wind and obvious anti-static warning signs. It should be reminded that a device without a label does not necessarily mean that it is not sensitive to static electricity. When there is doubt about a component’s ESD susceptibility, it must be treated as an ESD-sensitive device until its properties can be determined.
③ An electrostatic safe working area must be established in the SMT patch production line, and various control methods are used to keep the electrostatic voltage generated below the safe threshold for the most sensitive components.
④ Constitute a complete electrostatic safe work area, which should at least include effective conductive table mats, special grounding wires, anti-static wrist straps, and floor mats to protect conductors (such as metal parts, conductive tapes, conductive containers, and human bodies, etc.) discharge static electricity. At the same time, it is equipped with a static eliminator to neutralize the accumulated charges on the insulator. These charges cannot flow on the insulator and cannot be released by leakage grounding.
Anti-static in the production process
① Regularly check the grounding system inside and outside the workshop. The grounding system outside the workshop should be tested once a year. The resistance is required to be below 2Q. It needs to be retested when the line is changed. The grounding system of the carpet/board and table mat should be tested every 6 months, and the grounding resistance is required to be zero. If the resistance between the detection machine and the ground wire is positive, the resistance is required to be 1MQ, and the detection record should be made.
② Measure the temperature and humidity in the workshop twice a day, and make effective records to ensure constant temperature and humidity in the production area.
③Anyone must take anti-static measures before entering the SMT patch workshop. Operators who are in direct contact with the PCB, wear an anti-static wrist strap and require the operator who wears the wrist strap to test once a day in the morning and afternoon before going to work to ensure good contact between the wrist strap and the human body. At the same time, arrange technical personnel to supervise and inspect every day. Provide anti-static knowledge training and on-site management to employees when necessary.
④When holding the PCB by hand during the production process, you can only hold the edge of the PCB where there are no electronic components; after production, the PCBA must be packed in an anti-static package;
During the rework operation, the PCB to be repaired must be placed in an anti-static box and then brought to the rework station.
⑤The tools used in the whole production process should have the anti-static ability.
⑥The PCBA that has passed the test and acceptance should be sprayed once with an ion spray gun and then packed.
Storage and use of electrostatic-sensitive devices
①The SSD must not be dropped on the ground during transportation, and must not be arbitrarily separated from the package.
②The relative humidity of the warehouse where the SSD is stored should not be lower than 40%.
③The original packaging should be kept during the storage of the SSD. If the packaging needs to be replaced, an anti-static container should be used.
④In the warehouse, an anti-static special label should be placed on the position where the SSD is placed.
⑤ When distributing SSDs, use the method of visual inspection, and check the quantity in the original packaging of SSDs.
⑥Manual welding, rework, and debugging should be carried out in the static-safe area.
ESD 10 daily self-inspection steps
①Check your workstation to ensure that there are no static-generating objects (such as plastic bags) or static-generating tools on the workbench.
② Check whether the grounding wire of your station is disconnected or loose, especially after the instrument or equipment has been moved.
③If you use an ion fan, turn on the switch to check whether it is normal.
④Remove objects that are prone to static electricity in the working area, such as plastic bags, boxes, foam, tapes, and personal items, and place them at least 1m away.
⑤Ensure that all ESD-sensitive parts, components, or products are properly placed in conductive containers and not exposed.
⑥Make sure that no items prone to static electricity are placed in conductive containers with ESD-sensitive signs.
⑦ Make sure that all conductive containers are affixed with corresponding electrostatic warning signs.
⑧ All cleaning tools, solvents, furs, and sprays must be approved in writing by the ESD supervisor.
⑨Do not allow any person without grounding measures to enter within 1m of the ESD electrostatic protection zone. Anyone who enters the electrostatic protection area or touches any items must take measures and wear electrostatic protective clothing.
⑩Wear wrist straps or ankle straps and electrostatic protective clothing. Measure the wrist strap or ankle strap according to the demonstration method of the ESD supervisor.
Summarize ESD protection during SMT processing
In short, the electrostatic protection project is becoming more and more important in the SMT industry. It involves a wide range and is a systematic project. A mistake in a certain link will lead to irreparable losses. Therefore, first of all, we must do a good job teaching and training people so that personnel at all levels realize its importance and can work on the job only after passing the training. Do a good job of anti-static work.
The above content is shared by SZTech-SMT about electrostatic protection during SMT chip processing. I hope it will be helpful to you. To learn more about SMT chip processing, please visit www.sztech-smt.com
