During PCBA processing, there are many production processes and many quality problems are prone to occur. At this time, it is necessary to continuously improve PCBA welding methods and improve the process to effectively improve product quality.

1. Improve welding temperature and time

The intermetallic bonds of copper and tin form grains, the shape and size of which depend on the duration and intensity of the temperature during welding. Less heat during welding creates a fine crystalline structure, resulting in a superior weld joint with optimal strength. PCBA patch processing reaction time is too long, whether it is due to too long welding time or too high temperature or both, it will lead to a rough crystal structure, which is gritty and brittle, and the shear strength is relatively low. Small.

2. Reduce surface tension

The cohesive force of tin-lead solder is even greater than that of water, making the solder spherical to minimize its surface area (for the same volume, a sphere has the smallest surface area compared to other geometric shapes to meet the needs of the lowest energy state) . The effect of flux is similar to the effect of detergent on metal plates coated with grease. In addition, surface tension is also highly dependent on the cleanliness and temperature of the surface. Only when the adhesion energy is much greater than the surface energy (cohesion) can ideal welding occur. tin.

2. PCBA board soldering angle

When a drop of solder is placed on a hot flux-coated surface at a temperature approximately 35°C above the eutectic point of solder, a meniscus is formed, which, to some extent, affects the ability of the metal surface to pick up tin. This can be assessed by the shape of the meniscus. If the solder meniscus has a pronounced undercut edge, resembles a drop of water on a greased metal plate, or even tends to be spherical, the metal is not solderable. Only the meniscus stretches to less than 30°. The small angle has good weldability.