| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of the difference of a plating film thickness in a longitudinal direction and burned deposits by lowering plating currents when only the front end and rear end of a rectangular frame exist in plural plating cells and the plating area is small in the case this frame is continuously treated by using plural plating cells. SOLUTION: When the lead frame 30 comes into contact with a first cathode 25 of the first plating cell 24, the current is supplied from a first current rectifier 21. When the lead frame 30 is fed into a second plating cell 26 while its front end comes into contact with a second cathode 27, the currents are supplied from a second current rectifier 22 besides from the first current rectifier 21. The lead frame 30 further advances and comes into contact with a third cathode 28. When the lead frame passes through the second plating cell 26, the currents are supplied from the first, second and third current rectifiers 21, 22, 23. When the rear end of the lead frame 30 enters the first cell in succession, the contact with the first cathode 25 is interrupted and, therefore, the supply currents are those from the first and second current rectifiers 22, 23. Further, the rear end of the frame 30 comes into contact only with the third cathode 28 when the rear end passes the second cell. |
