PCB News - If the PCB board factory finds that the PCB solder mask is not evenly covered, how to fix it?

If the PCB board factory finds that the PCB solder mask is not evenly covered, how to fix it?

Regarding the solder mask rework, if the PCB shipped by the PCB board factory finds that the solder mask is not evenly covered, how to repair it? If the green oil blisters after the PCB is wave soldered, can it usually be repaired? Are there any relevant regulations that say that green paint is feasible? How to make up?

Uneven coverage of PCB soldermask

Uneven coverage of PCB solder mask

If there is no leakage of metal on the circuit board surface, there should be no need to repair it, but the appearance is not good, and customer acceptance is not a problem. If it is indeed broken and want to repair, you should clean the exposed metal surface and prepare a solder resist mixed with hardener, repair it with a brush, and send it to the oven to bake and harden after the repair is completed. The above are the methods that can be taken when the hole phenomenon occurs, but there is no way to answer the uneven coverage question you asked. Unless it is deliberately specified, most of the circuit board products are based on non-leakage of copper. The solder resist will have a certain degree of thickness difference. If the quality is too poor, it must be scrapped, and I am afraid it cannot be repaired.

In theory, after wave soldering, if the green paint peels off, the surface will be stained with solder. After cleaning it up and doing moderate repairs, there should be no problem in function, but whether the customer can accept this quality situation must be communicated. At present, there is no clear public specification for this kind of repair work, and both parties must jointly establish acceptable standards. I haven't heard that there are special repair pens. The general industry tends to use the brush repair method more often, but it is recommended that the pen tip should be strong and not lint. Generally, the brushes used for repairing are reused, so after use, they must be cleaned to avoid residues, otherwise subsequent repairs will cause pollution problems.

If a large number of fixed area repairs or missing printing needs occur, it is recommended to make repairs with silk screens for printing repairs. This treatment is not only more tidy in appearance, but also more stable. As for products that cannot be printed after assembly, brush repair is still a more feasible way at present, the above is for your reference.