In the circuit board SMT patch processing, electric welding on the tin is a key stage, associated with the performance indicators of the circuit board and the appearance of the design beautiful and

generous condition, in the specific production and manufacturing will be caused by some reasons, such as the common spot welding on the tin is not round, will immediately harm the quality of

SMTSMT patch processing. The following is a detailed introduction of the PCB factory’s SMT patch processing spot welding on the tin is not round reason.

The key reasons why the solder on the spot welding of the SMT patch of the circuit board factory is not round:

1, spot welding position solder paste amount is insufficient, resulting in the tin is not round, there is a gap;

2. The expansion rate of the welding liquid in the welding paste is too high, which is very easy to crack;

3, the wettability of the welding fluid in the solder paste is not very good, and it can not exceed the very good tin provisions;

4, PCB board welding pad or SMD welding position has a relatively serious air oxidation condition, endangering the actual effect of tinning;

5, the specificity of the welding liquid in the welding paste is insufficient, and the air oxidation chemicals in the welding position of the PCB circuit board or SMD welding can not be removed;

6, if a part of the spot welding on the tin is not round, the reason will be that the red glue can not be sufficiently mixed before application, and the welding liquid and tin powder can not be sufficiently combined;

7. The heating time is too long or the heating temperature is too high in the reflow furnace, resulting in the specific ineffectiveness of the welding liquid in the welding paste.