Summary of the key points of soldering iron welding technology
1. Selection of soldering iron
The power of an electric soldering iron should be determined by the size of the soldering point. The area of the soldering point is large, and the heat dissipation speed of the soldering point is also fast, so the selected electric soldering iron should have a higher power. The power of a general soldering iron is 20W, 25W, 30W, 35W, 50W, and so on. It is more appropriate to use a power of around 30W during the production process.
After prolonged use, a layer of oxide will form on the tip of the soldering iron, making it less susceptible to tin corrosion. In this case, a file can be used to remove the oxide layer, and the soldering iron can be energized. When the tip of the soldering iron is slightly hot, rosin can be inserted and coated with solder to continue using. Newly purchased soldering irons must also be tinned before use.
2. Soldering and soldering 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
Components must be cleaned and tinned. Electronic components are stored in air, and due to oxidation, there is a layer of oxide film attached to the pins of the components, as well as other dirt. Before welding, the oxide film can be scraped off with a small knife and immediately coated with a layer of solder (commonly known as tinning) before welding. After the above processing, the components are easy to solder firmly and are less prone to virtual soldering.
(1) Welding temperature and welding time
When welding, the temperature of the soldering iron should be higher than the temperature of the solder, but not too high. It is better for the soldering iron tip to just come into contact with the rosin and smoke. 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 virtual soldering. Conversely, if the welding time is too long, the solder is easy to flow and the components are prone to overheating and damage.
(2) The number of soldering points on the solder joint
The amount of solder on the welding point cannot be too small. If it is too small, the welding will not be firm and the mechanical strength will be too poor. And too much can easily result in a pile of appearances without internal connectivity. Soldering should just submerge all the component pins on the soldering point, and the outline should be faintly visible.
(3) Pay attention to the position of the soldering iron and soldering point
Beginners usually move or squeeze the soldering iron back and forth or forcefully at the welding point when welding, which is a wrong method. The correct method is to use the tinned surface of an electric soldering iron to contact the soldering point, which results in a larger heat transfer area and faster soldering speed.
