First, lead-free solder paste welding is a chemical link

Using solder paste to weld two different metals together is fundamentally different from using glue to glue two different materials together. During the welding process, the solder paste melts and forms a metal chemical bond between the two metals. The chemical molecules of the solder paste completely enter the interior of the welding material, forming a strong and fully cohesive structure. The solder paste itself becomes a part of the structure, and cannot be completely removed from the surface of the metal when dissolved, because the lead-free solder paste itself has become a part of the middle of the two metals. The use of glue to bond two materials together, these two materials are held together by their mechanical bond, so we often see that it is difficult to glue two very bright surfaces together. There is a fundamental difference between using glue and solder paste. One is a physical connection, the other is a chemical connection, and the way they are connected is completely different.

Two, the wetness of lead-free solder paste

Today, lead-free solder paste manufacturers will explain the importance of moistness of solder paste in popular terms. We all have the experience of washing dishes and chopsticks in our daily life. When we dip the greasy bowl into water, the bowl is not soaked by water, and when we take the bowl out of water, there is no trace of moisture on the bowl. Lead-free solder paste manufacturers call this phenomenon that the bowl is not soaked by water. The ability of water to wet the bowl belongs to wettability. In the process of solder paste welding, the effect of wetting is also the same as that of washing the dishes. If solder paste can not wet the surface of electronic components and circuit boards, it is very difficult to weld the two materials together.

Three, lead-free solder paste cleaning ability

As mentioned above, when we clean an oily bowl and enter the water again, we may be surprised to find that the water makes the surface of the bowl wet. It shows that the water at this time has good wetting for the surface of the bowl. The same principle when we use lead-free solder paste manufacturer's products in welding, if the surface of the circuit board or the surface of the electronic components have oil, at this time, how will the solder paste do? The solder paste will use its cleaning ability to remove stolen material from the surface of the material to be welded as it melts. This is the cleaning ability of the solder paste, through the solder paste itself will be composed of materials on the surface of the circuit board and electronic components to clean up the stolen goods, then wet after welding.

4. Capillary action of lead-free solder paste after melting

In the welding process of wave peak furnace, wave peak welding manufacturer will have plugged in the electronic components of the circuit board, through the top of the wave peak furnace. At this time, the solder in the tin furnace contacts the back of the circuit board, and the high temperature liquid tin enters the pad, and the whole pad is filled. If the circuit board surface is not clean, there will be no wetting and capillary force, the solder paste will not fill the pad. In the process of lead-free solder paste manufacturers, because a large amount of metal tin melts, forming a capillary effect on the surface of the circuit board, through the solder paste wettability to fill the solder joint, so as to complete the whole solder paste welding process.

Five, the tension of lead-free solder paste

Solder paste manufacturers know that everyone has seen a mosquito walking on the water, the mosquito can float on the water, and his feet will not be wet, because the mosquito foot contact with the water has a thin layer of tension to support it. This tension is the surface tension of water. Let's go back to the dishwashing process described by the lead-free solder paste manufacturer. When the water is placed on the bowl covered with grease, the water will maintain a random state. When the bowl is cleaned with dishwashing liquid, the water will not drop on the bowl, and it will completely moisten the bowl. When solder paste is used for welding, if the surface of the circuit board is also greasy, then lead-free solder paste is difficult to wet the pad on the circuit board, and it will not complete the whole welding process. In the use of solder paste in the process of welding added flux, its role is equivalent to dishwashing detergent, can be the circuit board welding pad above the oil to clean, reduce the surface tension of the whole pad. So that the solder paste can be more quickly on the board surface of the solder plate wet, solvent will remove the circuit board oil stains, reduce the tension of the circuit board surface metal.

The above is the whole solder paste welding process introduced by the lead-free solder paste manufacturer. Generally speaking, various additives in the solder paste want to clean and wet the bowl in the dishwashing process. In the added flux, there needs to be the same ingredients as washing detergent to clean the circuit board surface, so that the solder paste can be well moistened on the circuit board and electronic components after melting. To assist in the completion of the entire welding.