Lead-free environmentally friendly
solder wire uses lead-free solder to replace traditional tin-lead eutectic solder, which makes the process of lead-free environmentally friendly solder wire have significantly different characteristics. First, the temperature of the soldering process increases significantly, and the process window shrinks sharply. The commonly used lead-free solders are tin-silver-copper and tin-copper series alloys. The melting points of these two alloys are about 217°C and 227°C, respectively, which is higher than the melting point of 183°C of traditional tin-lead eutectic solder. 34~44℃. The maximum temperature in actual use is 20~30°C or more higher than that of the traditional process.
Secondly, since the wettability of lead-free solder used in lead-free environmentally friendly solder wire is significantly lower than that of tin-lead solder, in order to obtain good solder joints that meet the standards, it is necessary to ensure that the soldered surfaces such as component lead pins and PCB pads have better solderability. Also, since the traditional tin-lead solderability coating must be replaced, and more is replaced by pure tin coating, it is indeed very difficult to maintain better solderability of lead-free environmentally friendly solder wire without causing other problems. The problem is the same for lead-free solder bars.