Summary of soldering essentials for electric soldering iron
① Prepare for welding: hold the welding wire in the left hand and the soldering iron in the right hand, and enter the welding preparation state. The tip of the soldering iron is required to be kept clean, free of oxides such as welding slag, and a layer of tin is plated on the tip of the soldering iron. 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.
②Heating the weldment: Put the blade surface of the soldering iron head close to the solder joint, and heat the entire weldment for about 1 to 2 seconds. Pay attention to make the tip of the soldering iron touch the two objects to be soldered at the same time.
③ Feed the welding wire: The electric soldering iron is at an angle of about 60°C with the horizontal plane, so that the molten tin can flow from the soldering iron tip to the solder joint. When the welding surface of the weldment is heated to a certain temperature, the solder wire contacts the weldment from the opposite side of the soldering iron. The time the soldering iron tip stays at the solder joint is controlled within 2 to 3 seconds. Note: Do not send solder wire to the tip of the soldering iron!
④Remove the welding wire: When the welding wire melts a certain amount, immediately remove the welding wire to the upper left 45°.
⑤Remove the soldering iron: After the solder infiltrates the soldering pad and the soldering part of the weldment, remove the soldering iron in the upper right direction of 45° to end the welding, and then use the pliers to cut off the excess lead wire.
The time from sending the welding wire to removing the soldering iron is about 1-2S.
For weldments with small heat capacity, such as the connection of thinner wires on printed boards, it can be simplified to three steps.
① Prepare for welding.
②Heating and wire feeding: After the soldering iron head is placed on the weldment, the welding wire is put in.
③Removing the soldering iron: After the infiltration and diffusion of the solder on the soldering surface reaches the expected range, remove the soldering wire and the soldering iron immediately, and pay attention to the time of removing the soldering wire not lagging behind the time of removing the soldering iron.
For weldments that absorb low heat, the time of the welding process is only 2-4S.
Note: The power of the soldering iron used when soldering components is too high, it is easy to burn the components (generally, when the junction temperature of the diode and triode exceeds 200°C, it will burn out) and the printed wires will fall off the substrate; the power of the soldering iron used is too high. Small, the solder cannot be fully melted, the flux cannot be volatilized, the solder joints are not smooth and firm, and it is easy to produce false soldering. If the welding time is too long, the device will also be burned out. Generally, each solder joint is completed within 1.5-4S.
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 component is pulled out from the solder joint with a hand. These two situations will bring great difficulties to the debugging and maintenance of electronic production.
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. To remove 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.
