Summary of key points of electric soldering iron welding technology
1. Selection of electric soldering iron
The power of an electric soldering iron should be determined by the size of the solder joint. The larger the area of the solder joint, the faster the heat dissipation speed of the solder joint, so the selected electric soldering iron should also have a higher power. The power of a general electric soldering iron is 20W, 25W, 30W, 35W, 50W, and so on. It is more appropriate to choose a power of around 30W during the production process.
After prolonged use, a layer of oxide is formed on the head of an electric soldering iron, making it difficult to eat tin. At this point, the oxide layer can be removed with a file. After the soldering iron is powered on, rosin can be inserted when the head is slightly hot, and soldering tin can be applied to continue using it. Newly purchased electric soldering irons must also be tinned before use.
2. Solder and flux
Choose low melting point solder wire and non corrosive flux, such as rosin. Industrial solder and corrosive acidic solder oil should not be used. It is best to use solder wire containing rosin, which is very convenient to use.
3. Welding method
The components must be cleaned and tinned, and electronic components must be stored in air. Due to oxidation, a layer of oxide film is attached to the pins of the components, as well as other dirt. Before welding, a small knife can be used to scrape off the oxide film and immediately apply a layer of soldering tin (commonly known as tin lining) before welding. After the above treatment, the components are easy to solder firmly and are not prone to false soldering.
(1) Welding temperature and welding time
When welding, the temperature of the electric soldering iron should be higher than the temperature of the soldering tin, but it should not be too high, preferably when the soldering iron tip comes into contact with rosin and just smokes. If the welding time is too short, the temperature of the solder joint is too low, the melting of the solder joint is not sufficient, and the solder joint is rough, which can easily cause false soldering. Conversely, if the welding time is too long, the solder can easily flow and cause overheating and damage to the components.
(2) Number of tin applied to welding points
The amount of solder on the welding point should not be too small, as it is too small and the welding is not firm, and the mechanical strength is also too poor. And too much can easily cause a lot of appearance and internal disconnection. Solder should just immerse all the component pins on the soldering point, with the outline visible.
(3) Pay attention to the position of soldering iron and welding points
When beginners are welding, they usually move the electric soldering iron back and forth or forcefully squeeze it at the welding point, which is a wrong method. The correct method is to use the tin coated surface of an electric soldering iron to contact the welding point, which has a large heat transfer area and fast welding speed.
4. Inspection after welding
After the welding is completed, it is necessary to check for solder leaks, faulty soldering, and short circuits of components caused by solder flow. False soldering is difficult to detect, so tweezers can be used to clamp the component pins and gently pull them. If shaking is found, repair welding should be carried out immediately.
