How to solve the problem of solder paste drying in SMT patch processing

Solder paste is a kind of soldering material produced with the SMT chip processing industry. It is a paste solder that is uniformly mixed with alloy powder and paste flux carrier. Many SMT chip processing manufacturers report that the solder paste is easy to dry during the production process. Below we will introduce the reasons and solutions for the solder paste to dry easily.

On the one hand, the solder paste is only used in a small area during the reflow soldering process, which is more likely to dry out than the solder paste in the solder paste box. At this time, the solder paste does not melt and the flux cannot cover the solder joints, resulting in poor solder joints. . At the same time, a small amount of solder paste is easier to transfer heat, and the high temperature actually makes the solder paste more difficult to melt. So we can properly adjust the reflow welding temperature curve to solve it, or welding in a nitrogen environment is a good way to solve such a problem.

On the other hand, the solder paste does not melt because its components contain easily volatile flux, which is also the reason why the solder paste is easy to dry. Among them, the flux with the largest solder paste content is rosin, which contains a large amount of rosin acid, which tends to lose its activity at excessively high temperatures. Therefore, the temperature of the welding process should be controlled to ensure that the temperature is around 200°C. Too high or too low is not suitable. At the same time, the quality of the thixotropic agent will also cause the solder paste to dry easily, and the poor quality of the thixotropic agent will affect the viscosity of the solder paste, and the high viscosity solder paste will easily dry. Therefore, choosing high-quality solder paste can effectively solve the problem of easy drying of the solder paste.

In addition, the use environment, humidity, temperature and other external factors of the solder paste will affect the drying and non-melting phenomenon of the solder paste during use, so these external factors should also be paid attention to. Hope these methods can solve your problem.