The circuit board will not be well tinned 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 the production and processing of circuit boards? How to solve this problem after it occurs?

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

　　2. The tin surface of the circuit board or parts is oxidized and the copper surface is dull.

　　3. There are flakes on the surface of the circuit board and there is no tin on the surface of the circuit board, and there are particulate impurities in the plating layer on the board.

　　4. There are grease, impurities and other sundries on the surface of the circuit board, or there is residual silicone oil.

　　5. The high-potential coating of the circuit board is rough, there is burning phenomenon, and the surface of the board has flakes and cannot be tinned.

　　6. The circuit board has a complete coating on one side, and a poor coating on the other side, and there are obvious bright edges on the edges of the low-potential holes.

　　7. There are obvious bright edges on the edges of the low-potential holes of the circuit board, and the high-potential coating is rough, and there is a phenomenon of burning.

　　8. There is no guarantee of sufficient temperature or time during the circuit board soldering process, or the soldering flux is not used correctly

　　9. The circuit board can not be tinned on a large area at low potential, and the surface of the board is slightly dark red or red, with a complete coating on one side and a poor coating on the other side.

　　BGA circuit board (PCB circuit board)

　　Improvement and prevention plan of defective circuit board tinning:

　　1. The components of PCB syrup are regularly tested and analyzed to supplement in time, increase the current density, and extend the plating time.

　　2, PCB strengthens the pre-plating treatment.

　　3, PCB soldering flux should be used correctly.

　　4, PCB Hertz tank analysis adjusts the content of the light agent.

　　5. PCB checks the anode consumption from time to time and replenishes the anode with a reasonable amount.

　　6. PCB reduces the current density, and regularly maintains the filter system or performs weak electrolysis treatment.

　　7. Control the temperature of the circuit board during the welding process at 55-80℃ and ensure that there is sufficient preheating time.

　　8. Strictly control the storage time and environmental conditions of the storage process, and strictly operate the circuit board production process.

　　9. Use a solvent to clean the sundries. If it is silicone oil, 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 design the wiring or splicing of the circuit board, and adjust the light agent.

Read recommendations:

Six-layer Immersion Gold Board (BGA)

Computer card board (four layers)

DIP plugin

SMT stickers

What is the difference between PCB hard board and FPC soft board.Hybrid circuit board PCB