PCBA Tech - SMT process is complex and common problems in processing

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 a factory, especially in this very mature enterprise in the electronics industry. SMT patch processing has already caused it. An industry that is beginning to take shape, and many units that require 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, the type and nature of the cleaning agent are required when cleaning, and the integrity and safety of the equipment and process need to be considered during the cleaning process.

Common problems in SMT patch processing?

Common problems with tin beading in SMT chip processing and soldering technology: insufficient preheating of the PCB board during reflow soldering; unfair setting of the reflow soldering temperature curve, the board surface temperature and the soldering area temperature before entering the soldering area There is a large interval; the solder paste is not able to completely return to room temperature when it is taken out of the cold storage; the solder paste is exposed to the air for a long time after it is opened; the tin powder splashes on the PCB surface during the patch; printing or During the transfer process, there is oil or water sticking to the PCB board; the flux itself in the solder paste is unfairly distributed, and there are solvents that are not easy to evaporate or liquid additives or activators.

The first and second reasons above can also clarify why the newly replaced solder paste is prone to such doubts. The main reason is that the currently set temperature profile does not match the solder paste used.

The third, fourth, and sixth reasons can be caused by improper manipulation by the user; the fifth reason can be caused by the improper storage of the solder paste or the failure of the solder paste after the expiration date. The solder paste is non-sticky or too sticky. Low, forming a splash of tin powder during placement; the seventh reason is formed by the solder paste supplier’s own production technology.

There are more residues on the board surface after SMT soldering: There are more residues on the PCB board surface after soldering, which is also a question that customers often report. The existence of more residues on the board surface affects the brightness of the board surface. It also has an inevitable impact on the electrical properties of the PCB itself; the main reasons for the formation of more residues are as follows: when the solder paste is implemented, the customer's board conditions and customer needs are not known, or other reasons caused by the wrong selection ; The content of rosin resin in the solder paste is too much or its quality is not good.