The solder wire is fed under the iron tip to prolong tip plating life and prevent the flux from burning off too rapidly. Upon tip extension, the solder wire contacts the tip thus melting the solder directly onto the solder pad and transferring thermal energy very rapidly. The solder feeding position can be set by programming the Z axis to raise or lower the solder wire location to feed directly into the desired area of the solder joint. This allows the solder to spread evenly around the joint for optimal results.