PCB News - Circuit Board Factory: Factors of Poor Tin on PCB and Prevention Plan

Circuit Board Factory: Factors of Poor Tin on PCB and Prevention Plan

The circuit board will exhibit poor tinning during SMT production. Generally, poor tinning is related to the cleanliness of the surface of the PCB bare board. If there is no dirt, there will be basically no poor tinning. Second, tinning When the flux itself is bad, the temperature and so on. So where are the 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 the part is seriously 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 burning phenomenon, and there are flakes on the surface of the plate without tin.
4. There are grease, impurities and other sundries on the surface of the circuit board, 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 soldering 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 side.

Improvement and prevention plan for the bad condition of PCB circuit board electric tin:
1. Strengthen the pre-plating treatment.
2. Correct use of flux.
3. Analysis of Hexcel cell to adjust the content of light agent.
4. Check anode consumption from time to time and add anodes reasonably.
5. Reduce the current density and regularly maintain the filter system or perform weak electrolysis treatment.
6. Strictly control the storage time and environmental conditions of the storage process, and strictly operate the circuit board production process.
7. Control the temperature of the PCB board at 55-80 degree Celsius during the welding process and ensure that there is a satisfactory preheating time.
8. Timed analysis of the ingredients of the syrup and timely replenishment, addition of current density, and extension of the electroplating time.
9. Use a solvent to clean the sundries. If it is silicone oil, then you need to use a special cleaning solvent for cleaning.
10. Reasonably adjust the distribution of anodes, reduce the current density by an appropriate amount, reasonably plan the wiring or splicing of the board, and adjust the light agent.