Pulse welding appts. improving welding quality

摘要

Pulse welding appts. such as a pulse arc welding appts. or a short-circuiting arc welding appts. utilising pulse discharge, has a pulse current waveform control circuit which feeds a desired pulse arc current to the arc welding power source that supplies pulse arc current to the welding load unit, the circuit being so designed as to effect optimum welding without adjusting or changing the circuit components. Even under various welding conditions or environments, it is allowed to prevent defective welding during the arc welding caused by the magnetic blow phenomenon and to prevent defective welding such as undercut or sputtering caused by disturbances in the welding torch. The pulse current waveform control circuit is realised as a microcomputerised digital circuit, and the pulse arc current is controlled by the control operation of a program, in order to realise a desired current control by changing the program but without changing the circuit. By utilising the memory, the optimum welding current waveform parameter or a desired arc length signal is learned during the first welding, and the arc length feedback control or the current waveform control is effected during the second welding using a program prepd. with the thus learned welding current waveform parameter or the desired arc length signal as a reference. Thus, the molten mass is prevented from being erroneously removed by the magnetic blow phenomenon, and a change in the arc length is suppressed that is caused by disturbance in the welding torch, contributing to improving the welding quality under various welding environments. @(88pp Dwg.No.1/28)@