What are the requirements for solder paste in the PCBA proofing process

MentionPCBA proofing patch, May not be so familiar to many people, because the scope of its application is relatively small. However, if you mention SMT, PCB, SMD components and other related aspects, it is estimated that everyone still knows something. In the PCBA proofing and placement process, the quality of the solder paste is very important. It will affect the quality of the entire patch component. So what performance requirements should the solder paste meet?

1. Metal content

Solder paste must be used during PCBA proofing, and the metal content generally needs to be controlled within an appropriate range. When the metal content increases, the viscosity of the solder paste will increase, which can effectively resist the force generated by vaporization during the preheating process. But the metal content should not exceed the standard, otherwise it will easily cause the circuit board to short circuit.

2. Degree of oxidation of metal powder

The higher the degree of oxidation of the metal powder in the solder paste, the greater the resistance of the PCBA proofing patch to the metal powder when soldering, and the solder paste is not easy to infiltrate between the pads and components, resulting in solderability. Sexual decrease. Therefore, we must pay attention to the storage of solder paste to avoid excessive oxidation.

3. The amount and activity of flux

In the process of PCBA proofing and patching, if the amount of solder in the solder paste is too much, it will cause partial collapse of the solder paste, resulting in tin beads, and too much tin beads will seriously affect the quality of the patch. Therefore, we must know how to control the amount of flux within a reasonable range to avoid an increase in product defect rates.

The above is about the requirements for solder paste in the PCBA proofing and placement process. I hope that after reading it, you can have a more in-depth understanding and understanding of it. When choosing a solder paste, you must choose a suitable solder paste for soldering according to the above three requirements, so that the quality of the processed components will be better.