Several methods of soldering leads with an electric soldering iron on a printed circuit board.
Printed circuit boards are divided into two types: single-sided and double-sided. The through holes on it are generally non-metallic, but in order to make the components more firmly and reliably soldered onto the circuit board, most of the through holes on printed circuit boards in electronic products are now metallized. The method of soldering leads onto a regular single panel:
(1) Straight shear head. The lead wire passes directly through the through-hole, and during welding, an appropriate amount of melted solder evenly surrounds the tinned lead wire above the solder pad, forming a conical shape. After it cools and solidifies, cut off the excess lead wire. (Specific methods can be found on the blackboard)
(2) Bury your head directly. The lead wire that passes through the through-hole only shows an appropriate length, and the melted solder buries the lead head inside the solder joint. This type of solder joint is approximately hemispherical in shape, although it is aesthetically pleasing, special attention should be paid to preventing false soldering.
Prevent welding defects
Welding technology is a fundamental skill that radio enthusiasts must master, and requires more practice to become proficient.
1. When selecting appropriate solder, low melting spot welding wire should be used for soldering electronic components.
2. Soldering flux, dissolve 25% rosin in 75% alcohol by weight as the flux.
3. Before using an electric soldering iron, tin should be applied. The specific method is to heat the soldering iron, and when it can just melt the solder, apply flux, and then evenly coat the soldering iron head with solder, so that the soldering iron head can eat a layer of tin evenly.
4. Welding method: Polish the solder pads and pins of the components with fine sandpaper and apply flux. Dip an appropriate amount of solder with a soldering iron tip, touch the solder joint, and wait for all the solder on the solder joint to melt and immerse the component lead. Then, gently lift the soldering iron tip up along the pins of the component and leave the solder joint.
5. The welding time should not be too long, otherwise it is easy to scald the components. If necessary, tweezers can be used to clamp the pins to help dissipate heat.
6. The solder joints should have a sinusoidal peak shape, a bright and smooth surface, with Wuxi spikes and moderate tin content.
7. After welding is completed, the residual soldering flux on the circuit board should be cleaned with alcohol to prevent the carbonized flux from affecting the normal operation of the circuit.
8. Integrated circuits should be soldered last, and the soldering iron should be reliably grounded, or the residual heat should be used for soldering after power off. Alternatively, use a dedicated socket for integrated circuits, solder the socket and then plug the integrated circuit in.
9. The electric soldering iron should be placed on the soldering iron holder.
