Circuit board requirements for soldering tin
Soldering tin is one of the important industrial links for connecting electronic components in soldering circuits. If there is no corresponding soldering process quality assurance, it is difficult to achieve design specifications for any well-designed electronic device.
In soldering tin, the following must be done:
1. The welding surface must be kept clean
Even for weldments with good weldability, the surface of the weldment may produce harmful oxide film, oil stains, etc. due to long-term storage and contamination. Therefore, the surface must be cleaned before the welding is performed, otherwise it is difficult to ensure the quality.
2. The temperature and time should be appropriate when welding, and the heating should be even
Before welding, debug the temperature of the temperature control station and use a thermometer to test whether the temperature of the soldering iron tip is consistent with the temperature control station. When the proper temperature is reached, the molten tin wire is wetted and diffused on the surface of the metal to be welded to form a metal compound. Therefore, to ensure that the solder joints are strong, it is necessary to have a proper soldering temperature.
At a sufficiently high temperature, the tin wire is sufficiently wetted and sufficiently diffused to form an alloy layer. However, too high a temperature is not conducive to welding. The welding time has a great influence on the wettability of the solder and the welded components and the formation of the bonding layer. Accurately grasping the welding time is the key to high quality welding.
3. Solder joints should have sufficient mechanical strength
In order to ensure that the welded part does not fall off or loose when subjected to vibration or impact, the solder joint needs to have sufficient mechanical strength. In order to make the solder joints have sufficient mechanical strength, soldering is usually performed by an automatic soldering machine, which can avoid the soldering of the soldered components and the short circuit between the solder joints and the solder joints.
4. Welding must be reliable to ensure electrical conductivity
In order to make the solder joints have good electrical conductivity, it is necessary to avoid the occurrence of solder joints. The virtual soldering means that the solder does not form an alloy structure with the surface of the object to be soldered, but simply adheres to the surface of the metal to be soldered. When welding, if only a part of the alloy is formed, and the rest does not form an alloy, the solder joint can pass current in a short period of time, and it is difficult to find a problem by measuring with a meter. However, as time goes by, the surface where no alloy is formed will be oxidized. At this time, the phenomenon of passing and breaking will occur, which will inevitably cause quality problems of the product. （PCB Prototype supplier china）
Stable, good quality solder joints should be: bright and smooth solder joints; solder layer is even and thin, and the ratio of the size of the pad is appropriate, the outline of the joint is faintly visible; the solder is sufficient, the skirt is scattered; no cracks, needles Hole, no flux residue.