Analysis of general types and technical requirements of electric soldering irons
Classification of electric soldering iron
Commonly used electric soldering irons are divided into two types: internal heating type and external heating type. The soldering iron tip of the internal heat soldering iron is outside the heating wire. This 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. Since the electric soldering iron used by each maintenance worker is different, it is inevitable that the maintenance quality cannot be guaranteed.
The temperature of the soldering iron
The melting point of tin is 231.8 degrees Celsius, and the temperature of the tip of the soldering iron is generally above 250°C -350°C. When the soldering iron is placed on the solder joint, due to the low temperature of the weldment, it will take a while to heat up. During this period, most of the flux is likely to volatilize or even Completely volatile, resulting in poor wetting due to lack of flux during wetting. At the same time, due to the large temperature difference between the solder and the weldment, the bonding layer is not easy to form, and it is difficult to avoid false soldering. Moreover, after the protective effect of the flux is lost, the solder is easily oxidized, and the quality cannot be guaranteed.
Working power supply of electric soldering iron
The electric soldering iron uses 220 V AC power supply to heat. The power cord and the shell should be insulated, and the resistance between the power cord and the shell should be greater than 2 0 0 M ohms. Commonly used soldering irons are 25W, 30W, 35W, 40W, 45W, and 50W. A more powerful electric soldering iron has a lower heating wire resistance.
Analysis of basic problems in the use of electric soldering iron
(1) 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. When not in use 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, it will easily lead to safety accidents.
(2) The power plug of the electric soldering iron has two poles, three poles, special purpose, etc., and the workbench is compatible.
(3) After the electric soldering iron is used for a period of time, there will be tin scale on the tip of the soldering iron. For effective soldering, it is necessary to remove the tin scale left by the tip of the soldering iron.
(4) When soldering integrated circuits, the electric soldering iron must be reliably grounded, or use residual heat for soldering after the power is cut off. Or use a special socket for integrated circuits, and plug the integrated circuit after soldering the socket.
(5) Do not burn the electric soldering iron empty. Cut off the power when not in use. In order to avoid burning the tip of the soldering iron and burning the heating wire due to accelerated oxidation. Empty firing will shorten its service life.
