The circuit board will show poor tinning during SMT production. Generally, poor tinning is related to the cleanliness of the bare PCB surface. If there is no dirt, there will be basically no bad tinning. Second, tinning When the flux itself is bad, the temperature and so on. So what are the main manifestations of common electrical tin defects in circuit board production and processing? How to solve this problem after presenting it?
1. The tin surface of the substrate or parts is oxidized and the copper surface is dull.
2. There are flakes on the surface of the circuit board without tin, and the plating layer on the board surface has particulate impurities.
3. The high-potential coating is rough, there is a burning phenomenon, and there are flakes on the surface of the board without tin.
4. The surface of the circuit board is attached with grease, impurities and other sundries, or there is residual silicone oil.
5. There are obvious bright edges on the edges of low-potential holes, and the high-potential coating is rough and burnt.
6. The coating on one side is complete, and the coating on the other side is poor, and there is obvious bright edge on the edge of the low potential hole.
7. The PCB board is not guaranteed to meet the temperature or time during the soldering process, or the flux is not used correctly.
8. There are particulate impurities in the plating on the surface of the circuit board, or grinding particles are left on the surface of the circuit during the production process of the substrate.
9. A large area of ​​low potential cannot be plated with tin, and the surface of the circuit board has a subtle dark red or red color, with a complete coating on one side and a poor coating on the other.