PCBA Tech - SMT patch process and solder paste classification

The process of SMT patch processing is very complicated, so many people have seen this business opportunity. After learning the process of smt patch processing, they opened factories, especially in the very mature places of the electronics industry. SMT patch processing has already created an early stage. A large-scale industry, and many units requiring fine craftsmanship will choose SMT chip processing plants for processing. So what are the precautions for SMT chip processing?

When SMT patch processing, you must pay attention to electrostatic discharge measures. It mainly includes the design of SMT patch and the re-established standards, and in order to be sensitive to electrostatic discharge during SMT patch processing, corresponding treatment and protection are carried out. Measures are very critical. If these standards are not clear, you can refer to the relevant documents to learn.

SMT chip processing must fully comply with the above evaluation standards of welding technology. When welding, ordinary welding and manual welding are usually used, and the welding technology that needs to be used when processing SMT chip As well as standards, you can refer to the welding technology evaluation manual. Of course, some high-tech SMT patch processing plants also carry out 3D construction of the products that need to be processed, so that the effect after processing will reach the standard, and its appearance will be more perfect.

After the SMT chip processing and welding technology is the cleaning measure, the cleaning must be strictly in accordance with the standard, otherwise the safety after the SMT chip processing will not be guaranteed. Therefore, when cleaning, the type and nature of the cleaning agent are required, and the integrity and safety of the equipment and process need to be considered during the cleaning process.

How to classify the solder paste for SMT chip processing?

The solder paste is an indispensable soldering material during the SMT chip processing and production process of the circuit board. The main component of the solder paste is tin powder and flux mixed into a paste. There are many types of solder paste. The editor of SMT chip processing factory will introduce the classification of solder paste:

smt patch processing

1. According to the melting point, it is divided into three types: high temperature, medium temperature and low temperature.

Commonly used high temperature is tin, silver and copper 305, 0307. There are tin-bismuth-silver at medium temperature, and tin-bismuth is commonly used at low temperature, which can be selected according to different product characteristics in SMT chip processing.

2. According to environmental protection requirements, it can be divided into leaded solder paste and lead-free solder paste (environmental protection solder paste)

The environmentally friendly solder paste contains only a small amount of lead. Lead is a substance harmful to humans. In the electronic products exported to Europe and the United States, the content of lead is strictly required. Therefore, lead-free processes are used in SMT chip processing. In the national control of environmental protection, the SMT chip processing industry in the next few years, the use of lead-free technology for SMT chip processing is a trend.

In the lead-free SMT chip processing process, it is more difficult to tin with lead process, especially in the case of BGA\QPN, etc., it will use high silver content solder paste. Commonly used in the market are three-point silver and 0.3 points of silver. Among the solder pastes, silver-containing solder paste is currently the more expensive one.

3. According to the fineness of tin powder, it is divided into No. 3 powder, No. 4 powder, No. 5 powder and solder paste

Selection: In the SMT chip processing of generally larger components (1206 0805 LED lights), No. 3 powder solder paste is used because its price is relatively cheap.

There are dense pin ICs in digital products, and No. 4 powder solder paste is used in SMT chip processing.

When encountering very precise soldering components such as BGA, and demanding products such as mobile phones, tablets, and SMT chip processing, No. 5 powder solder paste will be used.