In the welding process of PCBA processing, the worker is not operating properly or the solder material is not refined. The welding effect is not as expected. So what are the bad phenomena of PCBA processing and soldering? Bad soldering will cause circuit board faults? The following describes the solder joint defects and their causes.
(1) Pad peeling
Mainly due to the peeling of the printed circuit board due to the high temperature of the pad, the defective solder joint is liable to cause a malfunction of the component breaking.
(2) Asymmetric solder distribution
mainly due to poor solder or solder quality or insufficient heating. The strength of the defective solder joint is insufficient, and the failure of the component is easily caused by the external force.
(3) Whitening of solder joints
unevenness and dullness. Generally caused by the temperature of the soldering iron is too high, or the heating time is too long. The strength of the defective solder joint is insufficient, and the failure of the component is easily caused by the external force.
(4) Tip
The main reason is that the direction of the soldering iron is not right, or the temperature is too high, which causes the flux to sublimate. This bad solder joint can cause a short circuit between the component and the wire.
(5) Cold welding
The surface of the solder joint is in the form of bean curd. Mainly because the temperature of the soldering iron is not enough, or the soldering of the solder before the solidification of the solder, the poor solder joint strength is not high, the conductivity is weak, and it is easy to cause the component to open the circuit due to the external force.
(6) There are holes in the solder joint
the main reason is that the lead is poorly wetted, or the gap between the lead and the jack is too large. The bad solder joint can be turned on temporarily, but the component is prone to open circuit failure over a long period of time.
(7) Excessive solder
mainly due to the fact that the wire is not removed in time.
(8) Too little solder
mainly due to the premature removal of the welding wire, the poor solder joint strength is not enough, the conductivity is weak, and it is easy to cause the component to open the circuit due to the external force.
(9) The lead wire is loose and the weldment is movable
mainly due to the movement of the lead before the solidification of the solder, or the poor soldering of the lead solder, which is likely to cause the component to be unconductive.
(10) Solder joints mixed with rosin residue
mainly due to excessive flux or insufficient heating. The poor solder joint strength is not high and the conductivity is unstable.
(11) Virtual welding
The main reason for its occurrence is that the surface of the weldment is not clean, or the flux is poor, or the heating is insufficient. The strength of the defective solder joint is not high, and the continuity of the component is unstable.
(12) There are holes in the surface of the solder joint
mainly due to the excessive gap between the lead and the jack. The strength of the defective solder joint is not high, and the solder joint is easily corroded.
In PCBA processing, poor soldering materials, choice of soldering temperature, and length of soldering time can all affect the final quality of the solder.
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