Method and apparatus for short arc welding

An apparatus for welding by depositing drops of molten metal at the end of a welding wire into a weld puddle comprising:

• a power source having a current output in electrical communication with the welding wire;
• a feedback circuit that provides a real-time signal indicative of the heat input to each drop;
• and
• a controller coupled to the power source and having a feedback input coupled to the feedback circuit, for controlling the magnitude of the current provided to the welding wire in response to the heat input to each drop.

A method of welding by depositing drops of molten metal at the end of a welding wire into a weld puddle comprising:

• providing current to the wire:
• providing feedback, in real-time, indicative of the heat input to each drop;
• and
• controlling the magnitude of the current provided to the welding wire in response to the heat input to each drop.

A method of determining the length of stick out, comprising the steps of:

• providing an arc voltage setpoint;
• comparing the arc voltage setpoint to the arc voltage;
• integrating the comparison over time;
• summing the integrand with a required mass deposition rate error;
• and
• comparing the sum to known values.

A welding controller that determines the length of stick out, comprising:

• means for providing an arc voltage setpoint;
• means for providing arc voltage feedback;
• means for comparing the arc voltage setpoint to the arc voltage, wherein the means for comparing is connected to receive the arc voltage feedback and arc voltage setpoint;
• means for integrating the comparison over time, wherein the means for integrating is connected to receive the comparison;
• means for summing the integrand with a required mass deposition rate error, wherein the means for summing is connected to receive the integrand;
• and
• means for comparing the sum to known values, wherein the means for comparing is connected to receive sum.