In the process of PCBA smt, the solder joint quality of pcba board is very important. The solder joint quality will not only affect the operation and life of the whole machine, but also affect the appearance. So how to judge the quality of solder joints?
In smt PCBA factories, the appearance inspection of pcba boards is generally performed in accordance with the requirements of the IPC-A-610 standard. Because there are many types of solder joints, it is difficult to describe them easily. Therefore, we break down solder joints into multiple dimensions and evaluate them with a single requirement. This is a way to deal with complex problems and it is worth learning.
The pin traces of the through hole parts should be obvious and can be identified. This is an important indicator for judging whether the short pin is soldered. If a spherical appearance is formed, it is cold solder joint, which can judge the quality of the solder joint.
At the bottom soldering end, we need to control the quality of its soldering point. First of all, we do not allow the soldering end to protrude. The width of the soldering seam of the soldering point is greater than or equal to 50%. The side is not required, as long as it is wet.
Qualified solder joints usually have the following points:
1. Take the welding wire as the center and unfold it symmetrically in a skirt shape.
2. At the solder joint, the connecting surface of the solder is concave and naturally transitions. The interface between the solder and the weldment is smooth and the contact angle is as small as possible.
3． Smooth surface with metallic luster.
4． No cracks, pinholes, or slag inclusions.
5. No cold soldering, wrong soldering, missing soldering, etc.