The usage of rosin (soldering iron welding)
The soldering iron is not hot or not too hot when it is plugged in
1) Check whether the power supply voltage is lower than AC210V (the normal voltage should be AC220V), if the voltage is too low, it may cause insufficient heat and difficulty in soldering.
2) The soldering iron tip is oxidized or the fastening part between the root end of the soldering iron tip and the inner wall of the outer tube is oxidized.
How to use a soldering iron correctly
1. Select suitable solder, low melting point solder wire for welding electronic components should be selected.
2. Flux, use 25% rosin dissolved in 75% alcohol (by weight) as flux.
3. The electric soldering iron should be tinned before use. The specific method is: heat the electric soldering iron, and when it can melt the solder, apply flux, and then apply solder evenly on the soldering iron tip, so that the soldering iron tip can be eaten evenly A layer of tin.
4. Soldering method, polish the pads and component pins with fine sandpaper, and apply flux. Dip an appropriate amount of solder with the tip of the soldering iron and touch the solder joint. After the solder on the solder joint is completely melted and immersed in the component lead, the soldering iron tip is gently lifted away from the solder joint along the lead of the component.
5. The welding time should not be too long, otherwise it is easy to burn the components. If necessary, use tweezers to clamp the pins to help heat dissipation.
6. The solder joints should be in the shape of sine wave peaks, the surface should be bright and smooth, without tin thorns, and the amount of tin should be moderate.
7. After the soldering is completed, use alcohol to clean the residual flux on the circuit board to prevent the carbonized flux from affecting the normal operation of the circuit.
8. The integrated circuit should be soldered last, and the electric soldering iron should be reliably grounded, or use residual heat for soldering after power failure. Or use a special socket for integrated circuits, and then plug the integrated circuit after soldering the socket.
9. The electric soldering iron should be placed on the soldering iron stand.
Rosin is used as a flux in welding and acts as a flux.
Theoretically speaking, the melting point of flux is lower than that of solder, and its specific gravity, viscosity, and surface tension are smaller than that of solder. Therefore, when soldering, the flux melts first, and quickly flows and covers the surface of the solder to isolate the air and prevent the metal surface. Oxidation, and can react with the oxide film on the surface of the solder and the metal to be welded at high temperature to melt it and restore the pure metal surface. Appropriate soldering tin helps to solder out a satisfactory solder joint shape and maintain the surface gloss of the solder joints.
Rosin is the most commonly used flux, it is neutral and will not corrode circuit components and soldering iron tips.
If it is a newly printed circuit board, apply a layer of rosin perfume on the surface of the copper foil before soldering. If it is a circuit board that has already been made, it can be directly soldered. In fact, the use of rosin depends on personal habits. Some people will dip the tip of the soldering iron in rosin every time they solder a component; Dip some rosin on top. The use of rosin is also very simple, just open the rosin box and dip the energized soldering iron tip on it.
If solid core solder is used for welding, it is necessary to add some rosin; if rosin tin solder wire is used (flux is wrapped in the wire core), rosin is not required.
Since the metal surface will form a layer of oxide film after contact with air, the higher the temperature, the more severe the oxidation. This layer of oxide film prevents liquid solder from wetting the metal, just as oil on the glass will prevent water from wetting. Flux is a special material used to remove oxide film, also known as flux. Flux has three functions:
1. In addition to oxide film. The essence is that the substances in the flux undergo a reduction reaction to remove the oxide film, and the reaction product becomes suspended slag, floating on the surface of the solder.
2. Prevent oxidation. After it melts, it floats on the surface of the solder, forming an isolation layer, thus preventing oxidation of the soldering surface.
3. Reduce the surface tension, increase the fluidity of the solder, and help the solder wet the weldment.
