- Pretreatment Steps before Soldering
Before welding, the pins of components or the soldering areas on the circuit board need to be processed. Generally, there are three steps involved: "scraping", "tinning", and "testing".
Scraping": This step entails cleaning the soldering areas thoroughly before soldering. Usually, a small knife and fine sandpaper are used to clean the pins of integrated circuits and printed circuit boards, removing any dirt on them. After cleaning , generally, flux needs to be applied to the components that are to be disassembled.
"Tinning": It means tinning the scraped parts of the components. The specific procedure is to dip a rosin alcohol solution and apply it to the scraped soldering areas of the components. Then, press the hot soldering iron tip with tin on it and rotate them to ensure them evenly coated with a very thin layer of tin.
"Testing": This step requires using a multimeter to check whether all the tinned components are of reliable quality. If there are any components with unreliable quality or damaged components , they should be replaced with components of the same specification.
- Welding Steps
Once the pretreatment work before soldering is completed, formal welding can commence.
For different welding objects, the required working temperatures of the electric soldering iron are also different. To determine the temperature of the soldering iron tip, you can touch the soldering iron against rosin. If there is a "squeaking" sound, it indicates that the temperature is appropriate; if there is no sound and the rosin can only be made to condense difficulty, it means the temperature is too low; if the soldering iron tip smokes heavily as soon as it touches the rosin, it shows that the temperature is too high.
Generally speaking, the welding process mainly consists of three steps:
(1) First, melt a small amount of solder and rosin on the soldering iron tip, and aim the soldering iron tip and the solder wire at the solder joint simultaneously .
(2) Before the flux on the soldering iron tip has completely evaporated, touch the soldering iron tip and the solder wire to the solder joint simultaneously to start melting the solder.
(3) When the solder has wetted the entire solder joint, remove the soldering iron tip and the solder wire simultaneously.
The welding process usually takes 2 to 3 seconds. When welding integrated circuits, the amounts of solder and flux should be controlled strictly. Unplugging the power plug of the soldering iron and soldering while it is still hot,which can prevent the integrated circuits from being damaged due to insulation failure of the electric soldering iron or voltage leakage from the internal heater to the outer shell.
