Reasons for the detachment of solder resist ink on PCB circuit boards

After high-temperature treatment in the tin furnace, the ink on the PCB board will come off. So what is the reason for ink peeling on PCB circuit boards? What is the reason for S/M peeling after gold melting?

There are several reasons for the peeling of solder resist ink

1. The nature of solder resist ink itself is not sufficient to withstand the test of tin furnaces. This may be caused by expired solder mask ink or improper operation. Almost all solder resist inks used in PCB factories undergo heat resistance and reliability testing, so conventional problems should not occur. In this regard, it is necessary to check whether there are any changes in the material itself or the process.

2. It may be due to the influence of external forces, including flux supply and mechanical collision. Especially at high temperatures, the characteristics of solder resist ink are no longer as high as those at normal temperatures. At this point, the solder mask ink surface of the circuit board is affected by any external force. It is easy to scratch and peel off.

3. It is more likely that the PCB board will burst due to moisture absorption before applying solder mask ink or during storage. When water vapor is heated and vaporized, its volume expands nearly three hundred times, and the temperature instantly increases, causing the solder mask ink to soften. Solder resistant ink is easy to peel off. This problem may occur in the tin spraying process of circuit board production, or in the wave soldering, reflow soldering soldering and other assembly processes.

4. There are stains, dust, or partial oxidation on the surface of the PCB, resulting in insufficient ink adhesion. Volcanic ash grinding board removes oxides, grease, and impurities from the surface of the board, thoroughly cleans and coarsens the board surface, controls the roughness and cleanliness of the copper surface, and achieves the best effect on the roughness and uniformity of the copper surface, improving the bonding force between the PCB board copper surface and solder resist ink. Do a good job in daily maintenance of the grinding machine.

There are several possibilities for SMPEELING after melting gold

1. Perhaps the copper front treatment was not ideal.

2. It may be due to insufficient S/M drying before painting,

3. It is possible that the stagnation time is too long, resulting in the formation of an oxide layer,

4. It may be that the quality of the solder resist ink is not suitable for the gold process

5. Perhaps the polymerization degree of solder resist ink is not enough,

6. If you have undergone more than one high-temperature process, such as dipping and gilding together or twice, it may also occur. Because there are many possibilities, you need to analyze them in detail one by one, but generally speaking, using the S/M model is still important.