Electric soldering iron is required for component assembly and disassembly.
Preparations before welding
1. Get rid of the oxide layer and remove the oxide layer so that the tip of the soldering iron can be easily dipped in solder when soldering. Before using the electric soldering iron, use a knife or file to gently remove the oxide layer on the tip of the soldering iron. After the oxide layer is scraped off, the metal will be exposed luster.
2. Dip in flux. As shown in Figure b, after the oxide layer of the soldering iron tip is removed, power on the soldering iron to heat the soldering iron tip, and then dip the soldering iron tip in rosin (it is available in the electronic market, do not go to the vegetable market), and you will see rosin vapor on the tip of the soldering iron. (Patients with obsessive-compulsive disorder can test the temperature with their faces. When I was a child, every time my dad soldered the circuit board of the remote control with a soldering iron, I wanted to try the temperature of the smoking solder tip)
The role of rosin is to prevent the oxidation of the tip of the soldering iron at high temperature, and to enhance the fluidity of the solder, making it easier to solder.
3. Hang tin. When the tip of the soldering iron is dipped in rosin and reaches a sufficient temperature, rosin vapor will emerge from the tip of the soldering iron, apply solder to the head of the soldering iron tip, and apply a layer of solder to the tip of the soldering iron tip.
The advantage of tinning the tip of the soldering iron is to protect the tip of the soldering iron from oxidation and make it easier to solder the components. Burning black and oxidizing, it is difficult to solder components. At this time, it is necessary to scrape off the oxide layer and then hang tin to use it. Therefore, when the soldering iron is not used for a long time, the power supply should be unplugged to prevent the soldering iron from "burning to death".
4. Welding of components
When soldering components, first gently scrape off the oxide layer on the pins of the components to be soldered, then energize the soldering iron, dip it in rosin after heating, and when the temperature of the soldering iron tip is sufficient, place the soldering iron tip at an angle of 45° Press on the copper foil next to the pins of the components to be soldered on the printed circuit board, and then touch the solder wire to the tip of the soldering iron. After the solder wire melts, it will become liquid and flow around the pins of the components. When the solder is turned on, the solder cooling will weld the component pins and the copper foil of the printed circuit board together.
When soldering components, the soldering iron tip should not be in contact with the printed circuit board and components for too long, so as not to damage the printed circuit board and components. The welding process should be completed within 1.5 to 4 seconds. The solder joints should be smooth and the solder should be evenly distributed.
5. Disassembly of components
When removing the components on the printed circuit board, use the tip of the electric soldering iron to touch the solder joints at the component pins. After the solder at the solder joints melts, pull out the component pins on the other side of the circuit board. , and then solder another pin in the same way. This method is very convenient to disassemble components with less than 3 pins, but it is more difficult to disassemble components with more than 4 pins (such as integrated circuits).
To disassemble components with more than 4 pins, you can use a tin-absorbing electric soldering iron, or you can use an ordinary electric soldering iron to disassemble with the help of a stainless steel hollow sleeve or a syringe needle (available in the electronic market, and you can also use one for injection).
The disassembly method of multi-pin components is shown in the figure below. Use a soldering iron tip to touch a certain solder joint of the component. When the solder of the solder joint melts, put a syringe needle of a suitable size on the pin and Rotate to separate the component pins from the solder copper foil of the circuit board, then remove the tip of the soldering iron, and pull out the needle of the syringe later, so that the component pins are separated from the copper foil of the printed circuit board, and then use the same The method is to separate the other pins of the component from the copper foil of the printed circuit board, and finally the component can be pulled out from the circuit board.
