Heating Time of Electric Soldering Iron – Working Principle of Soldering
A 60W soldering iron has a high power, but it usually needs to be preheated for 3-5 minutes. Although you seem to be getting hot and emitting white smoke, it may not have reached the melting point of soldering. The preheating time of an electric soldering iron is also related to the usage environment. The preheating time will be longer in environments with high wind and low temperature. It is recommended to take some protective measures (such as adding a sleeve) for the electric soldering iron in low temperature and high wind environments to ensure that it can continue to heat up and reach a certain high temperature.
The new soldering iron may have a slight smoke and odor when used for the first time. There is a layer of anti-oxidation paint on the top of the soldering iron, which should be gently wiped off before use. The first use requires sufficient feeding of solder to the soldering iron tip, so that it can fully absorb the solder before soldering.
Welding principle of electric soldering iron
Soldering is a science, and the principle of soldering with an electric iron is to heat and melt the solid solder wire with a heated iron, and then use the effect of flux to make it flow into the metal to be soldered. After cooling, it forms a firm and reliable soldering point.
When the solder is tin lead alloy and the welding surface is copper, the solder first wets the welding surface. With the occurrence of wetting phenomenon, the solder slowly diffuses towards the copper metal, forming an adhesion layer at the contact surface between the solder and the copper metal, making the two firmly bonded. So soldering is accomplished through three physical and chemical processes: wetting, diffusion, and metallurgical bonding.
1. Wetting: The wetting process refers to the flow of melted solder along the fine concave convex and crystalline gaps on the surface of the base metal by capillary force, forming an adhesion layer on the surface of the welded base metal, so that the atoms of the solder and the base metal are close to each other, reaching the distance where atomic gravity acts.
Environmental conditions that cause wetting: The surface of the welded base material must be clean and free of oxides or contaminants.
Metaphorically speaking, when water drops onto lotus leaves to form water droplets, it means that water cannot wet the lotus. When water drops onto cotton, the water seeps into the cotton and wets it.
2. Diffusion: With the progress of wetting, the phenomenon of mutual diffusion between solder and base metal atoms begins to occur. Usually, atoms are in a thermal vibrational state in the lattice, once the temperature rises. Atomic activity intensifies, causing the melted solder and atoms in the base material to cross the contact surface and enter each other's lattice. The speed and quantity of atomic movement depend on the heating temperature and time.
3. Metallurgical bonding: Due to the mutual diffusion between the solder and the base metal, an intermediate layer - a metal compound - is formed between the two metals. In order to obtain a good solder joint, a metal compound must be formed between the welded base metal and the solder to achieve a strong metallurgical bonding state of the base metal.
