1. Unsuitable parts terminal materials. Inspect the parts so that the terminals are clean and well dipped. Silicone oil, general release agent and lubricating oil contain such oil, it is not easy to be completely cleaned. Therefore, in the manufacturing process of electronic parts, the chemical should contain silicone oil. The oxidation preventing oil used in the soldering furnace should also be noted for oils other than this type.
2. The preheating temperature is not enough. The preheating temperature can be adjusted so that the temperature of the side surface of the substrate part reaches the required temperature of about 90 ° C to 110 ° C.
3. There are too many impurities in the solder and it does not meet the requirements. The impurities in the solder can be measured on time, and if it does not exceed the standard, the standard solder is replaced.
4. The transfer operation of the substrate after the soldering is kept stable, and the substrate to be soldered is cooled and moved enough to avoid this problem. The solution is to have a tin wave again.