1. Oxidation or contamination of the soldering terminals, pins, and pads of the printed circuit board substrate, or the PCB pads are damp.
2. The adhesion of the metal electrode of the inductor terminal is poor or the single-layer electrode is used, which will cause the capping phenomenon at the welding temperature.
3. In the case of unreasonable PCB pad design, the shadow effect during wave soldering may cause solder leakage.
4. The PCB pad is warped, causing poor contact between the warped position of the PCB pad and the wave soldering.
5. The two sides of the conveyor belt are not parallel (especially when the PCB pad transmission frame is used), so that the PCB pad and the wave crest contact are not parallel.
6. The wave crest is not smooth, and the height of the two sides of the wave crest is not parallel, especially if the tin wave nozzle of the electromagnetic pump wave soldering machine is blocked by oxide, the wave crest will appear jagged, which is easy to cause missed soldering and false soldering.
7. The flux activity is poor, resulting in poor wetting. The preheating temperature of HPCB is too high, which will carbonize the flux and lose its activity, resulting in poor wetting.
8. Set the proper preheat temperature.
The solution to the false soldering of the circuit board after wave soldering
1. Use the new inductor if it is new. Do not store it in a humid environment, and do not exceed the specified date of use. The PCB pads should also be cleaned and dehumidified.
2. Wave soldering should choose a surface mount inductor with a three-layer terminal structure. The inductor body and the soldering end can withstand the temperature impact of more than two 260°C wave soldering.
3. When SMD/SMC adopts wave soldering, the component layout and arrangement direction should follow the principle of smaller components in front and avoid mutual shielding as much as possible. In addition, you can appropriately lengthen the remaining pad length after the inductor is connected.
4. The warpage of PCB pads is less than 0.8~1.0%.
5. Adjust the horizontal level of wave soldering machine and transmission belt or PCB transmission rack.
6. Clean the wave nozzle.
7. Replace the flux.
8. Set the ideal and appropriate preheat temperature.
