How to solder components with a soldering iron:
Pre-weld treatment
1. Remove the oxide layer on the welding part
A knife can be made from a broken saw blade. Scrape off the oxide layer on the surface of the metal leads to expose the metallic luster of the leads.
The printed circuit board can be polished with fine gauze paper, and then coated with a layer of rosin alcohol solution.
2. Component tin plating
Tin on scraped leads. After dipping the lead wire in the rosin alcohol solution, press the tip of the hot soldering iron with tin on the lead wire and turn the lead wire. The leads can be evenly plated with a very thin layer of tin. Before the wire is welded, the insulation sheath should be peeled off, and then the above two treatments can be performed before formal welding. In the case of multi-strand wires, they should be twisted together after polishing, and then tinned.
After the pre-welding treatment is done, the welding can be officially carried out.
(1) Hold the electric soldering iron in the right hand. Use needle-nose pliers or tweezers with your left hand to hold components or wires. Before soldering, the electric soldering iron should be fully preheated. Tin should be eaten on the blade surface of the soldering iron head, that is, a certain amount of solder should be brought on.
(2) Place the blade of the soldering iron tip against the solder joint. The electric soldering iron is at an angle of about 60° to the horizontal plane. To facilitate the flow of molten tin from the tip of the soldering iron to the solder joint. The time the soldering iron tip stays at the solder joint is controlled within 2 to 3 seconds.
(3) Lift the tip of the soldering iron. The left hand still holds the component. The left hand can only be released after the tin at the solder joint is cooled and solidified.
(4) Rotate the lead wire with tweezers to confirm that it is not loose, and then use the pliers to cut off the excess lead wire.
2. Welding quality
When welding, it is necessary to ensure that each solder joint is firmly welded and in good contact. To ensure the quality of welding.
The tin point should be bright, smooth without burrs, and the amount of tin should be moderate. Tin and solder are firmly fused. There should be no false welding and false welding.
False soldering means that only a small amount of tin is welded at the solder joint, resulting in poor contact and intermittent on and off. False welding means that it seems to be welded on the surface, but it is not actually welded. Sometimes the lead wire can be pulled out from the solder joint by pulling it out by hand.
When soldering the circuit board, be sure to control the time. If it is too long, the circuit board will be burnt, or the copper foil will fall off. When removing components from the circuit board, stick the tip of the electric soldering iron on the solder joint, and pull out the component after the tin on the solder joint melts.
