(1) Pre-compression stage-the electrode drops to the current-on stage, to ensure that the electrode is pressed against the workpiece, so that there is proper pressure between the workpieces.
(2) Welding time-the welding current passes through the workpiece and generates heat to form a nugget.
(3) Maintenance time—cut off the welding current and continue to maintain the electrode pressure until the nugget is solidified to a sufficient strength.
(4) Rest time-the electrode begins to be lifted to the electrode begins to fall again, start the next welding cycle.
In order to improve the performance of welded joints, it is sometimes necessary to add one or more of the following items to the basic cycle:
(1) Increase the pre-pressure to eliminate the gap between thick workpieces and make them fit closely.
(2) Use the preheating pulse to improve the plasticity of the metal, make the workpiece easy to fit tightly and prevent spatter; doing so during projection welding can make the multiple bumps evenly contact the plate before the energized welding, so as to ensure that the heating of each point is consistent.