Pre welding treatment and welding steps of electric soldering iron
(1) Pre weld processing steps
Before welding, the soldering parts of component pins or circuit boards should be treated, generally including three steps: "scraping", "plating", and "testing":
Scraping: It means doing a good job of cleaning the welding area before welding. The commonly used tools are small knives and fine sandpaper to clean the pins and printed circuit boards of integrated circuits, remove dirt from them, and after cleaning, it is generally necessary to apply soldering flux to the components to be disassembled.
Plating: It is the process of tin plating on the cleaned parts of electronic components. The specific method is to dip in rosin alcohol solution and apply it to the cleaned soldering area of the component, then press the hot soldering iron with tin onto it, and rotate the component to evenly coat it with a thin layer of tin.
"Test": It is to use a multimeter to test whether all tin plated components are reliable in quality. If there are components with unreliable quality or damaged components, they should be replaced with components of the same specification.
(2) Welding steps
After completing the pre welding treatment, formal welding can be carried out.
Different welding objects require different working temperatures of the soldering iron. When determining the temperature of the soldering iron head, the electric soldering iron can be touched with rosin. If there is a "squeaking" sound, it indicates that the temperature is appropriate; If there is no sound and only the rosin can barely melt, it indicates that the temperature is too low; If the soldering iron tip emits a large amount of smoke when it comes into contact with rosin, it indicates that the temperature is too high.
Generally speaking, there are three main steps in welding:
(1) Melt a small amount of solder and rosin on the soldering iron head, and align the soldering iron head and wire with the solder joint at the same time.
(2) When the flux on the soldering iron head has not yet evaporated, simultaneously touch the soldering iron head and solder wire to start melting the solder.
(3) After the solder infiltrates the entire solder joint, simultaneously remove the soldering iron head and solder wire.
The welding process is generally recommended to take 2-3 seconds. When soldering integrated circuits, it is necessary to strictly control the amount of solder and flux used. In order to avoid damaging the integrated circuit due to poor insulation of the soldering iron or the induction voltage of the internal heater on the shell, the method of unplugging the power plug of the soldering iron and welding it while it is hot is often used in practical applications.
