Patent of a kind of wire-controlled swivel chair tray

Before replacing a new integrated circuit, all the solder left by the original integrated circuit should be removed to ensure that the pad is flat and clean. Then clean the pins of the integrated circuit to be soldered with fine sandpaper, evenly tin-plate, align the pins of the integrated circuit to the corresponding solder joints of the printed board, and lightly press them on the surface of the integrated circuit by hand during soldering to prevent the integrated circuit from moving.

With the other hand, operate the soldering iron and dip it in a proper amount of solder to weld and fix the pins at the four corners of the integrated circuit with the circuit board, then check and confirm the model and direction of the integrated circuit again, and then formally weld it after it is correct.

Adjust the temperature of the soldering iron to about 250℃. One hand holds the soldering iron to heat the pins of the integrated circuit, and the other hand sends the welding wire to the heating pins for welding until all the pins are heated and welded.

Finally, carefully check and eliminate pin short circuit and virtual welding. After the solder joint cools naturally, use a brush dipped in absolute alcohol to clean the circuit board and solder joint again to prevent welding slag.

Extended data:

The arc length is related to the type and thickness of covered electrode coating. However, short arcs, especially low hydrogen covered electrode, should be used as much as possible. Long arcs may cause blowholes. Short arc can prevent harmful gases such as O2 and N2 in the atmosphere from invading the weld metal and forming undesirable impurities such as oxides, which will affect the welding quality.

Suitable welding speed depends on covered electrode diameter, coating type, welding current, heat capacity of welding object, structure beginning and other conditions, so it is impossible to make standard provisions. Keeping proper welding speed, slag can cover the molten pool well. Make all kinds of impurities and gases in the molten pool have enough floating time to avoid slag inclusion and porosity in the weld.

When welding, if the rod feeding speed is too fast, the shrinkage stress will increase when the welding part cools, which will cause the weld to crack.