During the welding process of electronic components, the surface of the solder joint appears to be successfully welded, but it is not actually soldered. Sometimes, with just a flick of the hand, the lead can be pulled out of the solder joint, which is called false welding.
The causes of false welding
1. Poor soldering quality;
2. Poor reducibility or insufficient amount of flux;
3. The surface of the welded area is not pre cleaned and the tin plating is not firm;
4. The temperature of the soldering iron head is too high or too low, and there is an oxide layer on the surface;
5. Welding time is too long or too short, which is not well mastered;
6. When the solder has not yet solidified during welding, the welded components become loose;
7. Component pins oxidized.
The hazards of false welding
Virtual soldering is mainly caused by oxides and dirt on the surface of the metal to be soldered. Its solder joints become connected with contact resistance, leading to abnormal circuit operation, unstable phenomena of good and bad, increased noise without regularity, and significant hidden dangers to circuit debugging, use, and maintenance.
In addition, there are also some virtual solder joints that remain in good contact for a long period of time after the circuit starts working, making it difficult to detect. But under the selection of environmental conditions such as temperature, humidity, and vibration, the contact surface gradually oxidizes and the contact gradually becomes incomplete.
The contact resistance of virtual solder joints can cause local heating, and an increase in local temperature can further worsen the condition of incomplete contact solder joints, ultimately causing solder joints to fall off and the circuit to malfunction completely. This process can sometimes take up to one or two years.
According to statistics, nearly half of the malfunctions in electronic products are caused by poor welding. However, it is not easy to find the faulty virtual solder joints from an electronic device with thousands of solder joints.
