Introduction to the difference between the power and size of the electric soldering iron
The electric soldering iron is a vital tool in the electrical repair process, but many maintenance workers who have only recently encountered the soldering iron are unaware of the standard that is used to determine the power of the electric soldering iron during the welding process, and they frequently travel the globe with just one soldering iron. The most obvious effect is that the welding effect is subpar as a result of carelessness in soldering iron power selection.
The power of the electric soldering iron used is too large, 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 small, and the soldering tin cannot be fully Melting, the flux cannot volatilize, the solder joints are not smooth and firm, and it is easy to produce false welding. Generally, it is used for welding integrated circuits, printed circuit boards, CMOS circuits, decoration transistors, IC recorders, TV sets, for ordinary circuit experiments, generally 20W is appropriate, and for repairing vacuum tube machines, such as amplifiers and old instruments. , 35W is appropriate, and the external heating type is 45W. The wiring of the welding large transformer and the grounding trunk line on the metal base plate are 50W for the internal heating type and 75W for the external heating type. If you want to weld metal materials, you should use an external heating electric soldering iron above 100W. If conditions permit, amateur radio enthusiasts can be equipped with a 2OW internal heating type, a 35W internal or external heating type, and a 150W external heating type electric soldering iron, so that they can basically meet various welding needs.
Leaded solder, which has a composition of 63% tin and 37% lead and a melting point of 183°C, is the type of solder that is most frequently used. Lead-free solder, on the other hand, has a composition of 99% tin and a flux content of about 1%, and its melting point is 227°C. Lead solder has the advantages of having a low melting point, being simple to solder, and being inexpensive, but it is not environmentally friendly and lead is harmful to humans, so you must carefully wash your hands after soldering.To establish a specific distance between the head and the weldment while soldering, it is best to wear a mask or be in an area with bright light. Lead-free solder is being employed in companies for machine welding as awareness of environmental protection has increased. It is easy to understand why lead-free solder, which is sometimes challenging to melt when repairing imported electrical appliances, has a high melting point.
The electric soldering iron is an electric heating device, which can generate a high temperature of about 250°C after being energized. During the soldering process of the electric soldering iron, it is actually a process of heat conduction. When it contacts the soldering surface, the heat on the soldering iron tip is transferred to the solder, and the solder absorbs the heat, melts and flows, and forms a bright and round solder joint under the action of surface tension. . In the process of welding heat conduction, since metals are good conductors of heat, the heat transfer is faster. During the melting process of the solder, due to the heat loss of the soldering iron tip, its temperature will drop more or less. If the solder joint has a large area, it needs to absorb more heat to make the solder on it reach the melting point. If the soldering iron tip is small in size and stores less heat, the temperature drops faster, and the heat generated due to the small power of the soldering iron core is too late to replenish the lost heat. At this time, the most intuitive phenomenon is that the solder does not melt or does not melt completely. In this case, we have to use a high-power soldering iron for welding. On the contrary, if the welded parts are small, we don't need to use high-power soldering iron; if we use high-power soldering iron, we must pay attention to the welding time, otherwise too much heat will easily cause the circuit through which the current flows, and the circuit board will be damaged. , causing the printed copper foil to fall off. The specific power of the soldering iron is suitable, and there is no specific quantitative requirement. The long-term work experience accumulation of maintenance personnel is the best way to choose a soldering iron that suits you.
