Patent ID: 8557016

Claim:
A reducing dross method of lead-free solder, comprising the steps of: firstly producing alloy of reducing dross by a master alloy process, the alloy of reducing dross comprising Sn and 0.1 to 0.8 wt % P; analyzing a percentage of P of the lead-free solder to be modified in a soldering furnace; if the percentage of P of the lead-free solder is less than 0.008 wt %, adding the alloy of reducing dross into the lead-free solder until the percentage of P of the lead-free solder in the soldering furnace reaches within 0.008 to 0.015 wt % P; then sampling the lead-free solder in the soldering furnace at regular intervals to determine the percentage and a percentage loss of P of the lead-free solder in the soldering furnace; if the percentage of P of the lead-free solder in the soldering furnace is less than 0.008 wt %, adding the alloy of reducing dross calculated according to the percentage loss of P in an amount needed for maintaining the percentage of P of the lead-free solder as 0.008 to 0.015 wt %.