Why Causes and solutions of PCBA processing BGA solder joints not full reason

Why Causes and solutions of PCBA processing BGA solder joints not full?reason

PCBA processing BGA solder joint is not full reason

For this BGA problem, the root cause is inadequate solder paste. Another common reason for the formation of incomplete solder joints encountered in PCBA processing BGA repair is the core suction phenomenon of solder, BGA solder due to capillary effect flow into the through hole to form information. Patch bias or printing tin bias and BGA pad and defect through hole without solder film isolation may cause core suction phenomenon, resulting in not full BGA solder spot. In particular, if the solder resistance film is destroyed in the repair process of BGA devices, the phenomenon of core suction will be intensified, resulting in the formation of incomplete solder joints.

Incorrect PCB design can also lead to incomplete solder joints. If a bore is designed on the BGA pad, a large part of solder will flow into the bore. If the amount of solder paste provided is insufficient, low Standoff solder spot will be formed. The way to compensate is to increase the amount of solder paste printing, in the design of the steel mesh to take into account the amount of solder paste absorption hole, by increasing the thickness of the steel mesh or increase the size of the steel mesh opening to ensure that the amount of solder paste enough; Another solution is to use microporous technology instead of the disc hole design to reduce solder loss.

Another factor that contributes to poor solder joints is the poor coplanar nature of the device and PCB.?If the solder paste print quantity is sufficient.?However, the gap between BGA and PCB is not consistent, that is, poor coplanar will also appear incomplete solder joints.?This is especially true at CBGA.

PCBA processing BGA solder joint is not full solution

1. Print enough solder paste;

2. Cover holes with blocking welding to avoid solder loss;

3. PCBA processing BGA repair stage to avoid damage to welding resistance layer;

4. Accurate tone alignment for printing solder paste;

5. Accuracy of BGA fitting;

6. Correct operation of BGA components in repair stage;

7. Meet the coplanar requirements of PCB and BGA to avoid warping, for example, appropriate preheating can be taken in the repair stage;

8. Use microhole technology instead of disk hole design to reduce solder loss.