The solder bar will appear in the soldering process. The main reason for this phenomenon is the poor reducibility or insufficient amount of the flux. Below, I will analyze it for you.
The reasons for the false welding of the solder bar are: the temperature of the soldering iron tip is too high or too low, and there is an oxide layer on the surface; the surface of the soldered part is not cleaned in advance, and the tin is not strong; when the solder is not solidified during the soldering, the soldering components are loose; The welding time is not well controlled, too long or too short; the reducibility of the flux is poor or the amount is not enough. Among them, poor reducibility or insufficient amount of flux is the main reason. Under the action of environmental conditions such as temperature, humidity and vibration, the contact surface of the solder bar is gradually oxidized, and the contact gradually becomes incomplete. The contact resistance of the virtual solder joint of the solder bar will cause local heating, and the local temperature increase will promote the incomplete contact solder joint, which will further deteriorate the situation, and eventually even cause the solder joint to fall off, and the circuit can not work properly.
Therefore, false soldering of solder bars is a major hidden danger to circuit reliability and must be strictly avoided. When performing manual soldering operations, the price of solder bars must be paid special attention to.
