The correct use method and key skills of electric soldering iron!
1. Welding method.
Weld Check Short
(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.
A good solder joint should be bright, smooth and free of 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. These two situations will bring great difficulties to the debugging and maintenance of electronic production. Both of these conditions can only be avoided with extensive, careful welding practice.
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.
Flux (rosin and solder oil) is the key when soldering. Fresh rosin and non-corrosive solder oil can help you complete the soldering well, and can make the surface clean and beautiful. You can use more flux when you use it
3. Welding skills
During the maintenance fabrication process, welding work is essential. It not only requires the components to be fixed on the circuit board, but also requires that the solder joints must be firm and smooth. Therefore, the quality of the welding technology directly affects the success of electronic production. Therefore, welding technology is a basic skill that every electronic production enthusiast must master. , now introduce the main points of welding:
1). The choice of electric soldering iron
The power of the 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 power of the soldering iron should be larger. Generally, the power of the electric soldering iron is 20W 25W 30W 35W 50W and so on. It is more appropriate to choose a power of about 30W.
After the electric soldering iron has been used for a long time, a layer of oxide will be formed on the tip of the soldering iron. At this time, it is not easy to eat tin. At this time, you can use a file to file off the oxide layer. After the soldering iron is powered on, insert the rosin when the tip of the soldering iron is slightly hot. , You can continue to use it after applying solder, and the newly bought electric soldering iron must be tinned before it can be used.
2). Solder and flux
Choose solder wire with low melting point and non-corrosive flux, such as rosin. It is not suitable to use industrial solder and corrosive acid solder oil. It is better to use solder wire containing rosin, which is very convenient to use.
3). Welding method
Components must be cleaned and tinned. Electronic components are in storage. Due to the effect of air oxidation, a layer of oxide film is attached to the component pins, and there are other dirt. Before welding, the oxide film can be scraped off with a knife, and a layer should be applied immediately. Solder (commonly known as enamel), and then solder. After the above treatment, the components are easy to weld firmly, and the phenomenon of virtual welding is not easy to occur.
Soldering temperature and soldering time
When soldering, the temperature of the electric soldering iron should be higher than the temperature of the solder, but it should not be too high. It is better that the soldering iron tip contacts the rosin just before smoking. If the soldering time is too short, the temperature of the solder joints is too low, the solder joints are not fully melted, and the solder joints are rough and easy to cause false soldering. On the contrary, the soldering time is too long, the solder is easy to flow, and it is easy to cause the components to overheat and damage the components.
The amount of tin on the solder joint
The amount of solder on the soldering point should not be too small, if it is too small, the welding will not be strong, and the mechanical strength will be too poor. And too much is easy to cause a lot of appearance but not connected inside. The solder should just submerge all the component leads on the soldering point, and the outline should be faintly visible.
Pay attention to the position of the soldering iron and the soldering point
When beginners solder, they usually move the soldering iron back and forth or squeeze hard at the soldering place. This method is wrong. The correct method is to use the tin-coated surface of the electric soldering iron to touch the soldering point, so that the heat transfer area is large and the welding speed is fast.
4). Inspection after welding
After soldering, it is necessary to check whether there are missing soldering, virtual soldering, and component short circuits caused by solder flow. Welding is difficult to find, you can use tweezers to hold the component pins and pull it gently, if you find shaking, you should repair the soldering immediately
