How to hold a soldering iron
(1) How to hold a pen. Suitable for lightweight soldering irons such as 30W internal heating. Its soldering iron head is straight, and the head end is filed into a bevel or conical shape, which is suitable for soldering pads with a small area.
(2), fist method. It is suitable for high-power soldering irons. We generally do not use high-power soldering irons for electronic production (not introduced here).
Several methods of soldering leads on a PCB.
There are two types of printed circuit boards: single-sided and double-sided. The through holes on it are generally non-metallized, but in order to make the components soldered on the circuit board more firmly and reliably, most of the through holes of the printed circuit boards of electronic products are now metallized. The method of soldering the leads on the ordinary single-sided board:
(1) Straight through the cutting head. The lead wire goes through the through hole directly. When soldering, make an appropriate amount of molten solder evenly surround the tin-stained lead wire above the pad to form a cone shape. After it cools and solidifies, cut off the excess lead wire. (see the blackboard for the specific method)
(2), buried directly. The lead through the hole is only exposed to an appropriate length, and the molten solder buries the lead tip inside the solder joint. This kind of solder joint is approximately hemispherical. Although it is beautiful, special attention should be paid to prevent false soldering.
Prevent poor welding
Soldering is a basic skill that radio amateurs must master, and it takes a lot of practice to master it.
1. Select suitable solder, low melting point solder wire for welding electronic components should be selected.
2. Flux, use 25% rosin dissolved in 75% alcohol (by weight) as flux.
3. The soldering iron should be tinned before use. The specific method is: heat the soldering iron, and when the solder can be melted, apply flux, and then apply solder evenly on the soldering iron tip, so that the soldering iron tip can be evenly coated A layer of tin.
4. Soldering method, polish the pads and component pins with fine sandpaper, and apply flux. Dip an appropriate amount of solder with the tip of the soldering iron and touch the solder joint. After the solder on the solder joint is completely melted and immersed in the component lead, the soldering iron tip gently picks up along the lead of the component and leaves the solder joint.
5. The welding time should not be too long, otherwise it is easy to burn the components. If necessary, use tweezers to clamp the pins to help heat dissipation.
6. The solder joints should be in the shape of sine wave peaks, the surface should be bright and smooth, without tin thorns, and the amount of tin should be moderate.
7. After the soldering is completed, use alcohol to clean the residual flux on the circuit board to prevent the carbonized flux from affecting the normal operation of the circuit.
8. The integrated circuit should be soldered last, and the electric soldering iron should be reliably grounded, or use residual heat for soldering after power failure. Or use a special socket for integrated circuits, and then plug the integrated circuit after soldering the socket.
9. The electric soldering iron should be placed on the soldering iron stand.
