Patent ID: 9662736
Date: 2017-05-30
CPC Classifications: B23K

Claim:
1. A method of promoting droplet transfer of a welding system, comprising: transitioning a waveform between a positive polarity above zero and a negative polarity below zero within a repeated cycle, wherein the cycle includes the following: regulating an output current level of the waveform to a positive polarity background current level to sustain an electric arc between an electrode and a workpiece, producing a molten metal ball on a distal end of the electrode; dropping the output current level below the positive polarity background current level to approximately zero in response to the molten metal ball being produced, shorting to the workpiece and extinguishing the electric arc to allow the molten metal ball to wet into a puddle on the workpiece; automatically further decreasing the output current level into a negative polarity below approximately zero in response to the molten metal ball wetting into the puddle to induce the molten metal ball to pinch off from the distal end of the electrode; increasing the output current level within the negative polarity toward approximately zero as the molten ball pinches off from the distal end of the electrode onto the workpiece to re-establish an electric arc between the electrode and the workpiece; decreasing the output current level within the negative polarity below approximately zero to a negative peak current level of the waveform in response to re-establishing the electric arc; and increasing the output current level above zero to the positive polarity background current level producing a next molten metal ball on the distal end of the electrode; providing at least one heat-increasing current pulse wherein the output current level is between the positive polarity background current level and an intermediate positive current level in the positive polarity at the end of the cycle to maintain a temperature of the puddle, wherein the intermediate positive current level is greater than the positive polarity background current level and less than an absolute value of the negative peak current level re-establishing the arc and a duration of pulsing the output current level is based on a wire feed speed; the combination of steps repeated to promote the droplet transfer of the welding system.