Shenzhen Xingkexun Electronics Co., Ltd. Contact: Mr. Wu Tel: 0755-81486688
Address: Block D, Yiyuanda Scientific Research Park, Shilong Community, Shiyan Street, Baoan District, Shenzhen, Guangdong.
There are many brands and types of solder paste in SMT chip processing . How to buy high-quality solder paste is determined by the accumulated experience of smt manufacturers and professional purchasers.
Solder paste is a thixotropic fluid. The printing performance of the solder paste in smt processing, the quality of the solder paste pattern, and the viscosity and thixotropy of the solder paste have a great relationship. Since most of the current solder paste is printed in the air during the printing process, the temperature of the environment will also affect the quality of the solder paste. Excessive humidity, water vapor mixed into the solder paste, the serious consequence is that the solder balls are oxidized and splashed during reflow soldering in the smt patch, which is very dangerous and adversely affects the product; too low humidity can easily cause solder paste Solvent volatilization and viscosity decrease, resulting in filling and peeling. Therefore, the storage environment of the solder paste should be controlled, and the relative humidity is recommended to be controlled at (45% -70%) RH. Changes in ambient temperature will also cause viscosity fluctuations. It is best to control the ambient temperature around 23 degrees. There is one more point to note in the SMT patch. The solder paste printing environment must be clean and hygienic. Dust in the air falling in the solder paste may cause pores in the printing. Therefore, the solder paste storage must be kept clean and hygienic. No dust, no corrosive gas in the workshop.
smt solder paste
Recommended storage method for solder paste:
1. If the shipping time is about 4 days, the temperature environment is controlled at <10 ℃
2. Shelf life (refrigerated), about 3 ~ 6 months, its temperature environment is 0-5 ℃
3. Within 8 hours after the solder paste is taken out of the refrigerator at a stable time, the humidity is 30% -60% RH, and the temperature of the environment is 15% -25% ℃
Pay attention to the following requirements when using solder paste:
1. After the purchase of the solder paste, the time and shelf life of the solder paste should be reached in time, the model of the solder paste, and the serial number for each can of solder paste.
2. The solder paste should be stored in a sealed refrigerator in a constant temperature and humidity refrigerator at a temperature of 2-10 ° C.
3. If SMT placement is required, the solder paste should be taken out of the refrigerator at least 4 hours in advance, and the time, number, user and corresponding product should be written after taking out, and the solder paste must reach the room temperature in the work The bottle cap can be opened. If it is opened before the temperature has risen, it will cause the solder paste to easily absorb water vapor, and solder beads will occur during reflow. (Note: Do not place the solder paste directly next to a hot air heater, air conditioner, etc.)
4. After the solder paste is unsealed, it should be stirred for at least 5 minutes to make the components of the solder paste uniform.
5. According to the number of devices in the smt patch, the printed circuit board should be printed uniformly. Generally, 200-300 grams are added at a time. After printing, a little can be added appropriately.
6. When printing solder paste and performing SMT placement operations, it is required to take the edge of the PCB or wear gloves. To prevent contamination of the pcb.
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