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Steps and Precautions of Manual Soldering Circuit Board

Although the automation equipment has now been so advanced that it has replaced most of the manual work, the soldering still needs to be completed manually due to the peculiarity of some components and some components may not be recognized by the machine. The artistic and accurate soldering craft is an important indicator to test the skills of welder.Today, Speeda Electronics will show you the steps and precautions of manual soldering printed circuit boards.


The specific operation of soldering printed circuit board can be divided into five steps,which called the five-step engineering method. It should be strictly operated in order to get high soldering quality.

Soldering preparation: prepare the solder wire and the soldering iron. It should be emphasized at this time that the head of the soldering iron must be kept clean to get tin soldering (commonly known as eating tin)

Weldment heating: make the soldering iron contact with the soldering point. The first thing is to make sure that the soldering iron is heating all parts of the weldment, for example, the leading wire and bonding pad on the printed board should be heated. Secondly, pay attention to letting the flat part of the head of soldering iron contact the weldment with larger heat capacity, while its side or edge part touches the weldment with small heat capacity, so as to keep the weldment evenly heated.

Solder melting: when the weldment is heated to a temperature that can melt the solder, put the solder wire on the solder joint. Then the solder starts to melt and wet the solder joint.


Soldering removing: when a certain amount of soldering is melt, remove the solder wire.

Soldering iron removing:When the solder completely wets the solder joints,remove the solder ing iron.Note that the direction of removing the soldering iron should be approximately 45°.

Soldering according to the above steps is one of the keys to get a good solder joint. However, in the actual production, the most common way to violate the operation steps is that the soldering iron head contacts the solder wire first, rather than weldment. The molten soldering drops on the welded part that has not yet been preheated, which results in cold solder joint. Therefore, soldering iron head contacting with the weldment and preheating the weldment are of great significance to prevent cold solder joint.

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