Several common methods of anti-static errors in factories
As the electronic components processed by electronic factories become more and more sophisticated, there are more and more electrostatic sensitive components, and the sensitivity is getting higher and higher. Many electronic factories in China are using various anti-static products, but they have invested a lot of cost but have not seen the application. Some effects will still cause a large number of defective products and product quality problems due to static electricity damage.
We are here to describe several common methods of anti-static errors in factories for your reference in order to correct them in time.
1. Inspection of electrostatic protection products
Many factories have purchased a lot of anti-static supplies based on hearsay or based on information provided by suppliers, but they do not have special inspection equipment and do not understand inspection methods. Due to the uneven product quality, there are many confounders and counterfeiters. Carry out product qualification inspection.At the same time, because some products are non-permanent materials and have a certain service life, the factory cannot monitor these products by themselves.When the product fails, then use it in the factory, so that the electrostatic protection product does not really play an ideal role.
2. Grounding system error or low reliability
First of all, the design and burying of the grounding body should meet the grounding specifications, and its resistance should be less than 10 ohms. If it is shared with the power ground, it should be connected to the same potential, and the resistance should be less than 1 ohm. It should not be shared with lightning protection grounding, because lightning strikes will pass through the loop. Affect the product and may cause personal safety. When sharing with the power supply ground of the three-phase five-wire system, pay attention to the power ground wire and the neutral wire not to be mixed. It is recommended to use an independent and reliable grounding device. The grounding conductor of the grounding system used next should meet Material and wire diameter requirements, the cross-sectional area of the main trunk line should not be less than 100 square, the cross-sectional area of the branch trunk line should not be less than 6 square, the cross-sectional area of the grounding wire of fixed equipment and facilities should not be less than 1.25 square, the copper core grounding wire color should be universal Yellow-green is required. The final connection method, the grounding trunk line should be brazed, and the equipment connection terminal should ensure reliable contact and easy disassembly. At the same time, attention should be paid to rust and anti-corrosion, and no insulating material spraying is allowed. All kinds of clip-on connectors are allowed. But it is still recommended to use grounding terminals and spring washers, banana plug sockets. For connection reliability, you can use monitoring and alarm devices.
3. Correct use of anti-static shoes
Many factories are equipped with anti-static shoes, but the ground does not use anti-static materials or the anti-static function has failed. Human body static electricity can only be discharged to the ground through the shoe/ground system. Some workers also wear socks and insoles when using anti-static shoes However, these socks and insoles often do not have the ability to conduct static electricity, which will cause the human body to be insulated and become an isolated conductor with a large amount of static electricity. Some employees who sit and operate in some factories only wear anti-static shoes. Due to the sitting operation, their feet often It is a state of not touching the ground, and due to the pressure relationship, the effectiveness of the shoe/ground system cannot be guaranteed, so employees who are sitting and operating should wear an anti-static wrist strap. Anti-static shoes should be monitored frequently during use. In particular, it should be tested after washing, and replaced when it is damaged.
4. Correct use of anti-static clothing
Some factories use anti-static wrist straps and anti-static shoes but do not wear anti-static clothes, because anti-static wrist straps and anti-static shoes can effectively protect the human body from static electricity to the earth, but our daily wear clothes are easy to accumulate a lot of Static electricity, and clothing does not have a proper way to discharge, when it comes in contact with ESDS components, it will also discharge and damage electrostatic sensitive components. There are also some factories that use anti-static clothing, but employees cannot wear them properly, open, roll up sleeves, accessories, etc. This kind of problem makes the effect of electrostatic clothing lose. After washing, the anti-static clothing should be tested to see if it still meets the requirements, and those that do not meet the requirements should be replaced or disposed of. It is recommended to use mesh (longitude and weft conductive wire) anti-static clothing, and long-sleeved anti-static clothing , The cuff should be slightly close to the wrist. Environments with cleanliness requirements or high anti-static requirements should use one-piece anti-static clothing and groundable anti-static clothing.
5. Correct use of anti-static wrist strap
Anti-static wrist straps are one of the effective ways to discharge static electricity from the human body, especially for employees who are sitting and operating. The wrist strap is the only effective way to discharge static electricity from the human body. The correct use of anti-static wrist straps is particularly important. Wearing too loosely, the cable is stretched too long, the banana head is loosely inserted, the wristband is dirty, etc., all affect the function of the wristband, the alligator clip is loose or forgotten to clip, the wristband is flipped, and the wristband is worn. Outside the sleeve, the broken connection line directly causes the wrist strap to fail. Therefore, the wrist strap should pay attention to monitoring the practical effect according to the life.
6. Packaging issues
After the factory has invested a lot of manpower and material resources to prepare anti-static equipment and facilities and put into production, EPA has stacked a large number of insulating materials (plastic bags, paper, foam, etc.), sensitive parts and static power sources, turnover boxes, Tray trays, fillers, Non-antistatic materials are used for packaging materials such as tapes, or because customers provide invalid or ineffective antistatic packaging materials, or because the recycled packaging materials have expired and become invalid, etc., the factory inspection meets the requirements but the customer's incoming inspection A lot of problems were discovered.