Soldering iron specifications and selection requirements
1. The shape of the soldering iron tip adapts to the requirements of the surface to be soldered.
The heads of commonly used external heating electric soldering irons are mostly made into a chisel style. According to the requirements of the surface to be soldered, the angles of the chisel type soldering iron heads are 45°, 10°~25°, etc., and the width of the chisel opening also varies. same.
For products with high welding density, internally heated electric soldering irons commonly use round beveled tips, which are suitable for welding printed circuit boards and general solder joints.
In the welding of printed circuit boards, it is sometimes more convenient to use the notched soldering iron tip shown in Figure 1(f) and the hollow iron tip shown in Figure 1(g), but the repair of these two types of soldering iron tips is relatively complicated. trouble.
2) The temperature of the tip tip adapts to the melting point of the solder
Usually this temperature should be 30 to 80°C higher than the melting point of the solder, and should not include the temperature drop when the soldering iron tip contacts the solder joint.
3) The heat capacity of the soldering iron meets the requirements of the parts to be welded
The heat capacity is too small and the temperature drops quickly, resulting in insufficient melting of the solder, low strength of the solder joint, dark and dull surface, rough solder particles, and even virtual soldering.
Excessive heat capacity will cause the temperature of components and solder to be too high, which will not only damage the components and wire insulation layers, but may also cause blistering of the copper foil of the printed circuit board. The solder fluidity is too high and difficult to control.
4) The temperature recovery time of the soldering iron tip can meet the thermal requirements of the parts to be welded
The so-called temperature recovery time refers to the time required for the soldering iron tip to return to its original maximum temperature after the temperature of the solder joint drops. To make this recovery time appropriate, you must choose a soldering iron with suitable power, heat capacity, tip shape, length, etc.
5) Selection of soldering iron power
① To weld more precise components and small components, it is advisable to use a 20W internal heating soldering iron or a 25-45W external heating soldering iron.
② When welding continuous solder joints, a high-power soldering iron should be used.
③ For large solder joints and grounding tabs on metal base plates, an external heating soldering iron of 100W or above should be used.
