Tech: Introduction to the principle of
　　spot welding machine 　　 Spot welding machine, also known as resistance welding machine, is the principle of welding using the resistance heat generated by the welding point of the workpiece through the electric current.
　　When working, the two electrodes squeeze the workpiece, so that the two layers of metal form a certain contact resistance under the pressure of the two electrodes. When the welding current flows from one electrode to the other electrode, instantaneous thermal welding is formed at the two contact resistance points, and the welding current flows instantaneously along the two workpieces from the other electrode, forming a loop without damaging the internal structure of the workpiece to be welded.
　　In the process of spot welding, clean the surface of the weldment and send it between the upper and lower electrodes, apply pressure to make it contact well; energize the contact surfaces of the two workpieces to be heated, and partially melt them to form a nugget; maintain the pressure after the power is turned off. The nugget is cooled and solidified under pressure to form a solder joint; the pressure is released 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 great influence on welding quality.
　　The process of spot welding is to turn on the cooling water; clean the surface of the weldment, send it to between the upper and lower electrodes after precise assembly, pressurize to make it contact well; energize the contact surfaces of the two workpieces to be heated, and partially melt them to form a nugget; After electricity, the pressure is maintained, so that the nugget is cooled and solidified under pressure to form a solder joint; the pressure is released and the workpiece is taken out.
　　Preparation and installation of weldments: Before welding steel weldments, all dirt, oil stains, oxide scale and rust must be removed. For hot-rolled steel, it is best to pickling and sandblasting the welded parts or use a grinding wheel to remove the oxide scale. Although the uncleaned weldment can be spot welded, the service life of the electrode is severely reduced, and the output power and quality of spot welding are reduced together. The thin-coated medium and low-carbon steel can be welded directly.

In addition, users can refer to the following process data when using:
　　1. Welding time: When welding medium and low-carbon steel, the welder can adopt a strong standard welding method (instantaneous energization) or a weak standard welding method (long-term energization). Strong standard welding methods should be used in mass production, which can improve production efficiency, reduce power consumption, and reduce workpiece deformation.
　　2. Welding current: The welding current depends on the size, thickness and contact surface of the weldment. Generally, the higher the conductivity of the metal, the greater the electrode pressure and the shorter the welding time. At this time, the required current density also increases.
　　3. Electrode pressure: The purpose of the electrode applying pressure to the welded parts is to reduce the contact resistance at the solder joints and ensure the required pressure when forming the solder joints.
　　Shenzhen Site Technology Co., Ltd. is a high-tech production enterprise integrating R&D, production and sales of automated welding equipment and power battery PACK line equipment. The professional technical engineering team provides customers with timely and perfect pre-sales and after-sales services.