| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that viscosity is strong, tensile force at the time of detaching from a part to be soldered is large and a solder bridge is easily generated in Sn-Zn system solder, although lead free solder without using lead is developed for the soldering of a printed wiring board but Sn-Zn system solder which is one of solders has the advantages of a low melting point, of few lift-off phenomenon and inexpensive. SOLUTION: At the time of bringing the part to be soldered into contact with a jet wave for last finishing, the opposite direction jet wave of melted lead free solder, which circulates in the opposite direction of the transportation direction of the work to be soldered, is used in the inert gas atmosphere of low oxygen concentration and the work to be soldered is brought into contact with the jet wave in the opposite direction while a transportation elevation angleθ1 is transported in the angle of the range of 2 deg. to 15 deg.. |
