During SMT production of circuit boards, poor soldering may occur, which is generally related to the cleanliness of the PCB bare surface. If there is no dirt, there is basically no poor soldering. Secondly, poor soldering flux and temperature during soldering. So, what are the specific manifestations of common tin defects in circuit board production and processing? How to solve this problem after it occurs?

1. There are particle impurities in the plating layer of the board, or polishing particles left on the surface of the circuit during the manufacturing process of the substrate.

2. The board surface may be contaminated with grease, impurities, or residual silicone oil

3. The surface of the board has flakes that cannot be tinned, and the coating on the board has particle impurities.

4. The high potential coating is rough and there is a burning phenomenon on the board, and there are flakes on the board surface that cannot be tinned.

5. The tin surface of the substrate or component is severely oxidized and the copper surface is dull.

6. One side of the coating is intact, while the other side has poor coating, and there is a noticeable bright edge at the low potential hole edge.

7. There is a noticeable bright edge at the edge of the low potential hole, and the high potential coating is rough with a burning phenomenon.

8. Insufficient temperature or time is not guaranteed during the welding process, or the flux is not used correctly

9. Low potential large-area tin plating is not possible, with slight dark red or red color on the surface of the board. One side of the coating is intact, while the other side has poor coating.

Improvement and prevention plan for PCB board tin defects:

1. The composition of the medicine should be regularly analyzed and supplemented in a timely manner, increasing the current density and prolonging the electroplating time.

2. Regularly check the consumption of anodes and add anodes reasonably.

3. Adjust the content of the light agent through Herschel groove analysis.

4. Reasonably adjust the distribution of anodes, reduce the current density appropriately, design the wiring or splicing of the board reasonably, and adjust the light agent.

5. Strengthen pre-treatment before plating.

6. Reduce current density, regularly maintain or weakly electrolyze the filtration system.

7. Strictly control the storage time and environmental conditions during the storage process, and strictly operate the production process.

8. Use solvents to clean debris. If it is silicone oil, specialized cleaning solvents need to be used for washing

9. Control the temperature during PCB soldering at 55-80 ℃ and ensure sufficient preheating time

10. Use soldering flux correctly.