Soldering iron welding requirements
Soldering is one of the important links in the assembly process of electronic products. If there is no corresponding welding process quality assurance, any well-designed electronic device will be difficult to meet the design indicators. Therefore, when welding, the following points must be done:
1. Welding surfaces must be kept clean
Even for weldments with good weldability, due to long-term storage and pollution, harmful oxide films, oil stains, etc. may be produced on the surface of weldments. Therefore, the surface must be cleaned before welding, otherwise it is difficult to guarantee the quality.
2. When welding, the temperature and time should be appropriate, and the heating should be uniform
During welding, the solder and the metal to be welded are heated to the welding temperature, so that the molten solder wets and diffuses on the surface of the metal to be welded and forms a metal compound. Therefore, to ensure that the solder joints are firm, there must be an appropriate soldering temperature.
At a sufficiently high temperature, the solder can be fully wetted and fully diffused to form an alloy layer. Excessively high temperature is not conducive to welding. The soldering time has a great influence on the soldering tin, the wettability of the soldered components, and the formation of the bonding layer. Accurately mastering the welding time is the key to high-quality welding.
3. Solder joints must have sufficient mechanical strength
In order to ensure that the parts to be welded will not fall off or loosen when they are subjected to vibration or impact, the solder joints are required to have sufficient mechanical strength. In order to make the solder joints have sufficient mechanical strength, the method of bending the lead terminals of the components to be welded and then soldering can generally be used, but excessive solder accumulation should not be used, which will easily cause virtual soldering and gaps between solder joints and solder joints. short circuit between.
4. Welding must be reliable to ensure electrical conductivity
In order to make the solder joints have good electrical conductivity, it is necessary to prevent virtual soldering. False welding means that the solder and the surface of the object to be welded do not form an alloy structure, but simply adhere to the surface of the metal to be welded. During welding, if only a part forms an alloy and the rest does not form an alloy, this kind of solder joint can also pass current in a short period of time, and it is difficult to find the problem by measuring with an instrument. But as time goes by, the surface without alloy will be oxidized, and at this time, the phenomenon of on and off will appear, which will inevitably cause quality problems of the product.
In short, good quality solder joints should be: bright and smooth solder joints; the solder layer is uniform and thin, and the proportion to the size of the pad is appropriate, and the outline of the junction is faintly visible; the solder is sufficient and spread out in a skirt shape; no cracks, needles, etc. holes, no flux residue.
