| 摘要 |
There are problems in spot welding of aluminium alloy, etc. that tolerance is low when a large amount of current passes in a short space of time and nugget splitting occurs, that dissipation occurs in the case of soft steel sheet, etc. resulting in poor quality welding, and also that the operating rate decreases due to eliminating pickup at electrode tips. In order to resolve these problems, the present invention provides a method for varying the magnitude of the welding current of a resistance welding machine. The control method is changed from conventional PMW control to PAM control, and a rectification smoothing voltage (EDC) that is output to an inverter circuit is increased or decreased for a certain set time and by a certain set ratio. With this control method, there is little heat dissipation, nuggets with high thermal efficiency are generated, and energy can be saved and electricity can be conserved by employing PAM control. |
