Types and power of soldering irons and how to use soldering irons
Introduction to Soldering Iron
1. Types and power of commonly used electric soldering irons
Commonly used electric soldering irons are divided into two types: internal heating type and external heating type. The soldering iron tip of the internal heating type electric soldering iron is outside the heating wire. This electric soldering iron heats up quickly and is light in weight. The soldering iron tip of the external heating electric soldering iron is inserted into the heating wire. Although it heats slowly, it is relatively firm.
The electric soldering iron is directly heated by a 220V AC power supply. The power cord and the case should be insulated, and the resistance between the power cord and the case should be greater than 200M ohms.
Electronic hobbyists usually use 30W, 35W, 40W, 45W, 50W soldering irons. A more powerful electric soldering iron has a lower heating wire resistance. Ohm's law derivation formula: R=U/I=U/I*U/U=U^2/P
2. Precautions for the use of electric soldering iron
(1) The newly purchased soldering iron must be dipped in a layer of tin before use (energize the soldering iron, and then use the tin bar to approach the tip of the soldering iron when the soldering iron is heated to a certain point). File bright, then turn on the electric heating to heat up, dip the tip of the soldering iron with a little rosin, and tin it when the rosin smokes, so that the surface of the tip of the soldering iron is first coated with a layer of tin.
(2) After the electric soldering iron is energized, the temperature is as high as 250 degrees Celsius. When not in use, it should be placed on the soldering iron stand, but when it is not used for a long time, the power should be cut off to prevent the high temperature from "burning" the soldering iron tip (oxidized). It is necessary to prevent the electric soldering iron from scalding other components, especially the power cord. If the insulation layer is burned by the soldering iron without paying attention, it will easily lead to safety accidents.
(3) Do not hit the soldering iron violently, so as not to shock and break the heating wire or lead wire inside the soldering iron and cause malfunction.
(4) After using the soldering iron for a period of time, there may be tin dirt on the tip of the soldering iron. We can lightly wipe it off with a damp cloth when the soldering iron is heated. If there are pits or oxidized blocks, use a fine-grained file to repair or directly replace the soldering iron tip.
Welding operation posture and hygiene
The chemical substances volatilized by heating the flux are harmful to the human body. If the nose is too close to the tip of the soldering iron during operation, it is easy to inhale the harmful gas. Generally, the distance from the soldering iron to the nose should be at least not less than 30cm, usually 40cm is appropriate.
There are three ways to hold the electric soldering iron, as shown in Figure 1. The anti-grip method is stable in action, and it is not suitable for fatigue after long-term operation. It is suitable for the operation of high-power soldering irons. The overhand grip is suitable for operation with medium-power soldering irons or irons with an angled tip. Generally, when welding printed circuit boards and other weldments on the operating table, the pen holding method is often used.
There are generally two ways to hold solder wire, as shown in Figure 2. Since lead accounts for a certain proportion in the welding wire composition, it is well known that lead is a heavy metal harmful to the human body, so you should wear gloves or wash your hands after operation to avoid ingestion.
Use a soldering iron to configure a soldering iron stand, which is generally placed on the right front of the workbench. After using the soldering iron, it must be placed on the soldering iron stand safely, and be careful not to touch the tip of the soldering iron with wires and other objects, so as to avoid short circuit after the insulation is damaged by the soldering iron.
