After completing the pre-welding treatment, you can officially proceed with welding:
(1) Hold the soldering iron in your right hand. Use needle-nose pliers or tweezers in your left hand to hold the component or wire. Before soldering, the soldering iron must be fully preheated. The blade surface of the soldering iron tip needs to be tinned, that is, a certain amount of solder is put on it.
(2) Place the blade surface of the soldering iron tip close to the solder joint. The angle between the soldering iron and the horizontal surface is approximately 60°C. This allows the molten tin to flow from the soldering iron tip to the solder joint. The time the soldering iron tip stays at the solder joint is controlled to 2 to 3 seconds.
(3) Lift the soldering iron tip. The left hand is still holding the component. Wait until the tin at the solder joint cools and solidifies before releasing your left hand.
(4) Use tweezers to rotate the lead to make sure it is not loose, and then use offset pliers to cut off the excess lead.
Welding quality-----When welding, ensure that each solder joint is firmly welded and has good contact. To ensure welding quality, the typical characteristics are that the tin point is bright, smooth and without burrs, and the amount of tin is moderate. The tin and the object to be soldered are firmly integrated, and there should be no false soldering or false soldering.
Welding is a condition where only a small amount of tin is soldered at the solder joint, resulting in poor contact and occasional on and off. False welding means that it seems to be welded on the surface, but in fact it is not. Sometimes the lead can be pulled out from the solder joint by pulling it out by hand.
When soldering circuit boards, be sure to control your time. If it is too long, the circuit board will be burned or the copper foil will fall off. When removing components from the circuit board, you can stick the soldering iron tip on the solder joint and pull out the component after the tin on the solder joint melts.
How to replace components------In fact, replacing components couldn't be easier. It can be easily done with a solder suction device. All the solder on the component pins is sucked off. Here is a little trick for you. The current circuit Most of the boards are made of fine workmanship and use very little solder, making it difficult to melt off. Then we can add some solder to the pins and then use a solder suction device to make it much easier.
Another method is the one mentioned earlier, which is to use a soldering iron to melt the solder directly, but this is quite risky. You have to be careful that the solder joint is not completely melted, and you are afraid of burning the components if it is in contact for too long. The common method is to use tweezers to hold the component and pull it out when it is heated. When the temperature reaches the temperature, the component will be pulled out, but remember not to use too much force, otherwise the pin will be broken in the solder, which will cause trouble.
Of course, for the sake of safety, it is best to combine the two methods, because sometimes the component socket is too small and it is difficult to clean the solder suction device. At this time, if you remove the solder suction device, it will stick, so you can use Heat the soldering iron and remove.
