Soldering iron - basic requirements for soldering points
1. The solder joints must have sufficient mechanical strength to ensure that the welded parts will not fall off or loosen when they are subjected to vibration or impact. Do not use too much solder to accumulate, which will easily cause virtual soldering, short circuit between solder joints and solder joints.
2. Welding is reliable and has good electrical conductivity. False welding must be prevented. False welding means that the solder and the surface of the weldment do not form an alloy structure. It simply adheres to the metal surface being welded.
3. The surface of the solder joints should be smooth and clean. The surface of the solder joints should have good luster, and there should be no burrs, voids, and no dirt, especially harmful residues of flux. Choose the appropriate solder and flux.
The choice of soldering iron
1. The selection of electric soldering iron generally follows the following principles:
① The shape of the soldering iron tip should adapt to the surface requirements of the weldment and the assembly density of the product.
② The temperature of the tip of the soldering iron tip should be compatible with the melting point of the solder, which is generally 30-80°C higher than the melting point of the solder (excluding the temperature drop when the soldering iron tip touches the soldering point).
③ The heat capacity of the soldering iron should be appropriate. The temperature recovery time of the soldering iron tip should be adapted to the requirements of the surface of the weldment. The temperature recovery time refers to the time required for the temperature at the tip of the soldering iron tip to return to the highest temperature after the temperature of the tip of the soldering iron decreases due to heat loss during the soldering cycle. It is related to the power of the electric soldering iron, heat capacity, and the shape and length of the soldering iron tip.
2. The principle of selecting the power of the electric soldering iron is as follows:
① When soldering integrated circuits, transistors and other components that are vulnerable to heat, consider using a 20W internal heating or 25W external heating electric soldering iron.
② When welding thicker wires and coaxial cables, consider using a 50W internal heating type or a 45-75W external heating type electric soldering iron.
③ When soldering larger components, such as metal chassis grounding pads, an electric soldering iron with a power of 100W or more should be selected.
