When a robot welds a series of spot welds using simple current regulation for equivalent stackups, that some of them produce violent expulsions. There are conditions that make one spot weld application different than another even when spot welding the same material of the same thicknesses. Disturbances are gradually introduced into the manufacturing welding processes that brings variations into existance. Variations such as gaps, sealant and adhesive materials, coatings, forces, geometry, and much more bring challenges for welding.

New materials being brought introduced are creating greater challenges by narrowing the welding lobe. What used to be a lobe that varied by as much as 1000 amperes between an expulsion weld and an undersized weld is now reduced to a lobe of only 200 or 300 amperes.

RAFT (Resistive Adaptive Feedback Technology) is a tool that is becoming valuable for high speed automated welding lines that allow manufacturers to improve quality and throughput.