What is the reason for solder touch of wave soldering

Wave soldering is to make the soldering surface of the board directly contact with high-temperature liquid tin for welding purposes. The high-temperature liquid tin maintains a slope, and the liquid tin forms a wave-like phenomenon by special means, so it is called “wave soldering”.

Wave soldering solder touch phenomenon

1. Due to the phenomenon that the component pin are too long when the board is over-wave soldering, the component trimming should be pre-processed: the extension length of the component pins is 1.5-2 mm, which does not exceed this height. There will be no phenomenon
2. Because the circuit board process design is more and more complicated, the lead pin spacing is getting denser and denser, and the wave soldering phenomenon is touchedafter the soldering. Changing the pad design is the solution. For example, reducing the pad size, increasing the length of the pad exiting the wave side, increasing the flux activity/reducing the pin extension length is also a solution.
3. The phenomenon of solder touched between the components formed after the molten tin is wetted to the surface of the circuit boardin wave soldering. The main reason for this phenomenon is that the inner diameter of the pad is too large, or the outer diameter of the component is too small.
4. The component pin solder tin touch after the dense foot components are densely packed in a region to form a wave
5. Wave soldering solder touched due to excessive pad size
6. The phenomenon soldering touch after wave soldering due to poor solderability of component pins

What is the reason for wave soldering solder touch ?

1.Flux activity is not enough.

2. The wettability of the flux is not enough.
3. The flux applied is toolittle.
4. Non-uniform coating of flux. .
5. Part of the circuit board can not be coated with flux
6. the circuit board area is be coated with tin
7. Some pads or solder pin are heavily oxidized
8. Unreasonable layout of circuit boards (unreasonable distribution of parts )
9. The direction of working board is wrong.
10. the tin is not enough, or copper exceeds the standard; [excessive impurities cause the melting point of the tin liquid to rise.
11. The foaming tube is clogged and the foaming is uneven, leading the uneven coating of the flux on the circuit board.