After the spot welding parts are combined, the pressure is applied through the electrode, and the resistance heat generated by the current through the contact surface and adjacent area of the joint is used for welding. The welding machine is also called welding net machine. The welding machine is equipped with suitable electrode form and electrode material. The welding machine is mainly used for welding and forming equipment of various types of metal wire. Butt welding machine is also known as current welding machine or resistance touch welding machine. The rolling welding machine uses the resistance between the contact surfaces of two workpieces to make the contact surfaces of two metal butt joints heat up to melt and fuse in a short time through low voltage and large current. Rolling welding is also called seam welding. It is a method to replace the cylindrical electrode of spot welding with a pair of roller electrodes. The welded workpiece moves between the rolling plates, and produces a sealing weld with overlapping nuggets to weld the workpiece. Roll welding is widely used in thin plate welding of oil barrel, can, radiator, aircraft and automobile oil tank, rocket and missile sealing container. The spot welding machine is the application of resistance welding. It has the characteristics of high production efficiency, low cost, material saving and easy automation. According to the usage method of resistance welding machine, pneumatic foot ty