| 摘要 |
PURPOSE:To make satisfactory resistance welding feasible by controlling welding current to make the aging change of a resistance value between electrodes at the time of resistance welding of the specified value and thereby forming a proper molten part. CONSTITUTION:In making resistance welding, change of resistance between electrodes with the passage of time while current is flowing is detected by a resistance inputting section and the value is differentiated by a differentiating section 2. The maximum of differentiated value is stored in an arithmetic section 4 only while signals are being sent from a timing signal generating section 3 and the output is compared with reference value for judging from a setting section 5 in a judging section 6. When the maximum differentiation value is greater than the set value, a current decrease signal is outputted in a current controlling section 7 and when the value is smaller than the set value, a current increase signal is outputted. Thus, welding current is reduced or increased accordingly, and change of resistance between electrode with the passage of time during welding is controlled properly. By this way, a proper molten part is formed in the weld zone and good resistance welding is feasible automatically. |
