The circuit board will not be able to be tinned very well when it is produced by SMT. 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 poor, temperature, etc. So what are the main manifestations of common electrical tin defects in circuit board production and processing? How to solve this problem?
1. The tin surface of the substrate or parts is oxidized and the copper surface is dark.
2. There are flakes on the surface of the circuit board that cannot be tinned, and there are particulate impurities in the plating on the board surface.
3. The high-potential coating is rough, and there is a phenomenon of burning the board.
4. There are grease, impurities and other debris on the circuit board surface, or there is residual silicone oil.
5. There is obvious bright edge phenomenon on the edge of the low-potential hole, and the high-potential coating is rough, and there is a phenomenon of burning.
6.—The surface coating is complete, the coating on one side is poor, and there is obvious bright edge phenomenon 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 coating on the surface of the circuit board, or there are polishing particles left on the surface of the circuit during the production process of the substrate.
9. The low-potential large area cannot be plated with tin, and the surface of the circuit board is slightly dark red or red. One side has a complete coating, and the other side has a poor coating.
Improvement and prevention plan for poor electrical tinning of PCB circuit boards:
1. Strengthen the pre-plating treatment.
2. Correct use of flux.
3. Analysis of the Hexel cell to adjust the content of the light agent.
4. Check the anode consumption from time to time and add anodes reasonably.
5. Reduce the current density and regularly perform maintenance or weak electrolysis on the filtration system.
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 at 55-80°C during the soldering process of the PCB board and ensure that there is a sufficient preheating time.
8. Timely testing and analysis of the ingredients of the potion, timely addition, addition of current density, and extension of 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 washing.
10. Reasonably adjust the distribution of the anode, reduce the current density appropriately, plan the wiring or splicing of the board reasonably, and adjust the light agent.