Thank you to JLCPCB for the manufacturing of the PCB

The specific operation of soldering can be divided into 5 steps, known as the five-step engineering method, to obtain good welding quality that must be strictly operated.

1 Ready for soldering;

 Prepare the solder wire and the soldering iron.

At this point the special emphasis of the soldering iron head to keep clean, that is, can be stained with solder.

2 Heating welding;

The iron contact welding points, pay attention to the first thing to keep soldering iron heating welding parts, such as fuses on the PCB and solder are heated, secondly, to pay attention to let the flat part of the welding head (the most) contact heat capacity of the larger welding, welding head profile or edges contact heat capacity of the smaller welding parts, to maintain a uniform heat welding.

3 Melt solder;

When the solder is heated to a temperature at which it can melt, place the wire on the spot. The solder begins to melt and wet the spot.

4 Remove the solder;

Remove the solder wire after melting a certain amount of solder.

5 Remove the soldering iron;

 Remove the soldering iron after wetting the solder joint completely. Note that the soldering iron should be removed in a direction of approximately 45°.

Welding according to the above steps is one of the keys to obtaining good solder joints.

In actual production, one of the most vulnerable to the violation of operation steps approach is the iron head is not the first contact with by welding, but the first contact with the solder wire, molten solder dropped at the end of is preheated by welding parts, so it is easy to produce solder joints virtual welding, the welding head must contact with by welding, on the welding preheating is one of the important measures to prevent virtual welding.

Notes for manual welding circuit board

1. Observe whether each welding spot (copper skin) is smooth and oxidized before welding.

2. When welding articles, it is necessary to observe the welding point, so as to avoid a short cut caused by poor line welding.

There are a few things we should pay attention to when welding integrated circuits.
When welding an IC, if the IC pins are gold-plated, do not use a knife scratch, use a clean eraser instead.
For CMOS integrated circuit, if the lead has been shorted, do not remove the short route before welding.
It is advisable to use low-melting flux, and the temperature should not be higher than 150 ℃.
If the worktable is paved with rubber, plastic, and other materials easy to accumulate static electricity, integrated circuits and printing plates should not be placed on the table.
As integrated circuits are heat-sensitive devices, it is very easy to damage integrated circuits if welding temperature and welding time are strictly controlled.

And we should also pay attention to this issue when welding printed circuit boards.

Generally, internal heat type 20-35W or temperature-regulating electric soldering irons and soldering irons should be conical in shape according to the size of PCB soldering plates. The temperature of soldering irons should be adjusted to no more than 300 ° C during heating.
When heating, we should try to avoid letting the tip of the soldering iron stay in one place for a long time, so as not to cause local overheating, damage to copper foil or components.

When welding, do not use the method of friction solder pads to increase the wetting properties of solder, but the use of surface cleaning and pre-tin treatment.
When welding metalized holes, the solder should be wetted and filled to the entire hole, not just to the surface of the pad.