The spot welding machine adopts the principle of double-sided double-point overcurrent welding. When working, two electrodes press the workpiece so that the two layers of metal form a certain contact resistance under the pressure of the two electrodes, and the welding current flows from one electrode to the other electrode When the two contact resistance points form an instantaneous thermal welding, and the welding current flows from the other electrode along the two workpieces to this electrode to form a loop, and will not damage the internal structure of the welded workpiece.

The process of spot welding is to open the cooling water; clean the surface of the weldment, and after the assembly is accurate, send it between the upper and lower electrodes, apply pressure to make it contact well; electrify the contact surface of the two workpieces to heat and locally melt, forming Nugget: Keep the pressure after the power is off, so that the nugget is cooled and solidified under pressure to form a solder joint; the pressure is removed and the workpiece is taken out. Spot welding process parameters such as welding current, electrode pressure, energizing time and electrode working surface size have a significant impact on welding quality.