Welding techniques of electric soldering iron
shave
Scraping means that before welding, the surface of the welded metal should be cleaned as shown in Figure 3. A small knife, scrap steel saw blade, etc. can be used to scrape off (or use fine sandpaper or coarse rubber to wipe off) the oxide layer, oil stains, or insulation paint on the welding surface until a new metal surface is exposed. Before welding self-made printed circuit boards, it is also necessary to carefully polish one side of the copper foil with fine sandpaper or water sandpaper. Scraping is a key step to ensure welding quality, but it is often overlooked by beginners. If the scraping is not done properly, it will result in poor tin plating and welding. It should be noted that some component leads have already been silver plated, gold plated, or tinned. As long as there is no oxidation or peeling, there is no need to scratch them again. If there is dirt on the surface, use a thick rubber to erase it. The choice of thick rubber is best when using a large rubber for drawing. Some gold plated crystal transistor pins and leads may find it difficult to tin after scraping off the coating. No matter what form of "scraping" is used, it is important to continuously rotate the component pins and ensure that the entire circumference of the pins is clean.
plating
Plating is the process of tinning the parts to be welded. After scraping, the soldering parts such as the pins and wire heads of the components should be immediately coated with an appropriate amount of soldering flux, and a thin tin layer should be coated with an electric soldering iron to prevent surface oxidation and improve the solderability of the components. The solder layer to be plated should be thin and uniform, so the amount of solder on the soldering iron head should not be too much each time. For components such as crystal diodes and transistor that are afraid of scalding, it is necessary to use tweezers or pointed pliers to clamp the root of the lead pin in advance to help dissipate heat, and then proceed with tin plating treatment. Tin coating of components is an important process step in welding technology to prevent hidden dangers such as false soldering and false soldering, and should not be careless.
measure
Testing is the inspection of tin coated components to see if there is any damage, deformation, overlap welding (short circuit), etc. on the appearance of the components under the high temperature of the soldering iron. For components such as capacitors, transistors, integrated circuits, etc., a multimeter should also be used to check whether their quality is reliable. Components found to be unreliable or damaged should never be reused.
weld
Welding is the process of soldering qualified components to a printed circuit board or designated location as required. When welding, it is necessary to control the temperature and welding time of the electric soldering iron. If the temperature is too low or the time is too short, the tin surface will have a burrs like tail, the surface will not be smooth, and even appear like tofu residue. It is possible that due to the incomplete evaporation of the soldering flux, there is a certain amount of flux left between the soldering tin and the metal. After cooling, the soldering flux (rosin) will stick the soldering tin to the metal surface, and it can be pulled open with a little force, which is called false soldering.
