Patent ID: 6512200
Filing Date: 2003-01-28
Classification: B23K

Abstract:
A method of controlling an arc welding system operating in the dip transfer mode over a plurality of welding cycles, the welding system including a power source and a consumable electrode which in use is operative to be advanced into contact with a workpiece, the welding system being operative to create a welding circuit which is energised by said power source and wherein the welding cycle comprising an arcing phase where the electrode is spaced from said workpiece and an arc is generated across said space, the arc being operative to form a molten droplet on the end of the electrode, and a short circuit phase where the electrode is in contact with said workpiece, the welding cycle changeing from the arcing phase to the short circuit phase on contact of the molten droplet with the workpiece, and changing from the short circuit phase to the arcing phase after rupturing of a bridge of molten material formed between said electrode and said workpiece, the method including the steps of:(i) conditioning the welding system to form a molten droplet on the electrode end during the arcing phase which is within a predetermined threshold size range so that bridge rupturing can occur during the short circuit phase without requiring high current during the short circuit; and (ii) controlling the current output from the power source during the short circuit phase wherein in response to the detection of a short circuit, the current output is maintained at or below a first level both before and during bridge rupturing for at least the majority of the welding cycles, said first level being such that said current output will not induce excessive spatter on bridge rupturing.