Intelligent stepper welding system and method

An intelligent stepper welding system, comprising:

• a resistance welder having opposed electrode tips for spot welding;
• a power source operatively connected to the electrode tips for providing a weld current thereto;
• a sensor for measuring a voltage or resistance between the electrode tips;
• and
• a controller operatively connected to the sensor for receiving a voltage or resistance signal therefrom and operatively connected to the power source for adjustably controlling the weld current provided to the electrode tips, the controller configured to incrementally increase the weld current from the power source by a first fixed amount between successive spot welds by the welder and configured to decrease the weld current by a second fixed amount when the voltage or resistance measured by the sensor corresponds to a spatter condition, wherein the controller is further configured to initially increase the weld current from the power source by a third fixed amount or percentage when an initial resistance between the electrode tips is high and to initially decrease the weld current from the power source by a fourth fixed amount or percentage when the initial resistance between the electrode tips is low.

A welding control method for adjustably controlling weld current during successive welding of a plurality of spot welds, comprising:

• detecting a spatter condition during welding of the plurality of spot welds;
• decreasing the weld current and increasing cycle time when the spatter condition is detected;
• and
• otherwise increasing the weld current when indexing from one of the plurality of spot welds to the next of the plurality of spot welds.

An intelligent stepper method for adjustably controlling weld current during successive welding of a plurality of spot welds, comprising:

• a) starting at a first weld location of the plurality of spot welds;
• b) sensing welding parameters prior to welding;
• c) determining whether a modification to at least one of weld current or cycle time is needed based on the welding parameters sensed;
• d) if determined that a modification is needed in b), then determining whether spatter has occurred twice in succession;
• if spatter has not occurred twice in succession, modifying at least one of the weld current or the cycle time according to a first schedule, and
• if spatter has occurred twice in succession, determining whether spatter occurring twice in succession is a first occurrence;
• if a first occurrence, modifying at least one of the weld current or the cycle time according to a second schedule, and
• if not a first occurrence, modifying at least one of the weld current or the cycle time according to a third schedule;
• e) welding at the weld location;
• f) sensing a spatter condition;
• g) determining whether there is another of the plurality of spot welds to weld;
• and
• h) if determined that there is another of the plurality of spot welds to weld, then adjusting a base current and/or cycle time and returning to b).