FAQs

What is the Working Principle of Spot Welding Machine?

The AC spot welder adopts the principle of double-sided double-point overcurrent welding. When working, the two electrodes pressurize 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. When electrodes are used, an instantaneous thermal fusion is formed at the two contact resistance points, and the welding current flows from the other electrode along the two workpieces to this electrode to form a loop without damaging 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 partially melt, forming Nugget; maintain 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.

The spot welder uses the high temperature arc generated when the positive and negative poles are instantaneously short-circuited to melt the solder and the material to be welded on the electrode to achieve the purpose of combining them. The structure of the electric welding machine is very simple, it is a high-power transformer, which converts 220V AC into a low-voltage, high-current power supply, which can be DC or AC. The welding transformer has its own characteristics, that is, it has the characteristics of a sharp drop in voltage. After the electrode is ignited, the voltage drops, and the working voltage of the electric welding machine is adjusted. In addition to the primary 220/380 voltage conversion, the secondary coil also has a tapped voltage conversion. At the same time, there is also an adjustable iron core that is adjusted by an iron core. Electric welding machine is generally a high-power transformer, which is made by the principle of inductance. The inductance will produce a huge voltage change when it is switched on and off, and the high-voltage arc generated by the instantaneous short-circuit of the positive and negative poles is used to melt the solder on the electrode. To achieve the purpose of combining them.

Spot welding is a resistance welding method in which the weldment is assembled to connect the joint and pressed between two electrodes, and the base metal is melted by resistance heat to form a welding spot. Spot welding is mostly used for the connection of thin plates, such as aircraft skins, smoke pipes of aero engines, and car cab shells. The welding transformer of the spot welding machine is a spot welding electrical appliance, and its secondary has only one loop. The upper and lower electrodes and the electrode arms are used to conduct welding current and transmit power. Cooling water passes through transformers, electrodes and other parts to avoid heat generation. When welding, the cooling water should be passed first, and then the power switch should be turned on. The quality of the electrode directly affects the welding process, welding quality and productivity. Electrode materials are commonly made of red copper, cadmium bronze, chromium bronze, etc.; the shape of the electrode is various, mainly according to the shape of the weldment. When installing the electrodes, pay attention to keeping the upper and lower electrode surfaces parallel; the electrode planes should be kept clean, usually with emery cloth or files for trimming.