| 摘要 |
PURPOSE:To simplify a replacing and assembling work of a mask and a frame by reducing generation of a splash and a quantity of pressure marks inside of the frame when welding a spring into a frame. CONSTITUTION:When welding a spring into a frame 1, chrome copper is used as an electrode material for an outside welded electrode 3 and a tungsten silver compound is used as the electrode material for an inside welded electrode, while in respect of an area of the electrode end part the inside-welded electrode 4 is larger than the outside-welded electrode 3. Accordingly, current density (current/area) in an inside contact face is smaller than in the outside, while generation of splashes is less in the inside. Further hardness of the inside-welded electrode 4 is larger than that of the outside-welded electrode 3 so as to be able to prevent generation of a hollow of the inside welded electrode 4. In case also the inside and the outside are applied by the same pressure, the contact face of the inside-welded electrode 4 is large so that pressure per unit area for the frame 1 is small and a pressure mark of the electrode in the inside face becomes small. |
