The resistance welding machine is the basic principle of double-sided double-point overcurrent welding. During operation, the pressurized workpieces of the two electrodes cause the two metals to form a corresponding contact resistance under the pressure of the two electrodes. When passing from one electrode to the other, the welding current forms instantaneous thermal fusion at the two contact resistance points, and the welding current flows along the two workpieces from the other electrode to this electrode in an instant to form a circuit without damaging the internal structure of the welded workpiece.
The resistance welding machine process uses cooling water, removes the welded surface, assembles accurately, delivers the upper and lower electrodes, applies pressure to make good contact; heats the two workpiece contact surfaces and melts locally to form a molten core; maintains pressure after power failure so that the molten core cools under pressure to form a welded joint; removes pressure and removes the workpiece. Spot welding process parameters, such as welding current, electrode pressure, energizing time, electrode operating surface size, etc., have an important impact on welding quality.
The resistance welder uses a high temperature arc formed during an instantaneous short circuit to melt the welding material on the electrode and the welding material to bond them. The structure of a resistance welder is relatively simple. In short, it is a high-power transformer that converts 220V AC power into a low-voltage and high-current power source. It can be either DC or AC. The welding transformer has its own characteristics, i.e. it has a voltage dip.
After resistance welding combustion, the voltage is reduced and the working voltage of resistance welding machine is adjusted. In addition to the primary 220/380 voltage conversion, the secondary coil also has a tapped conversion voltage. In addition, it can also be adjusted using an iron core. The welding machine is usually a high-power transformer, which is made from the basic principle of inductance. The inductance creates a huge voltage change when the high-voltage arc formed when the positive and negative electrodes are short-circuited momentarily melts the solder on the electrode. For the purpose of combining them.
Spot welding is an assembly joint of welded parts, which is pressed between two electrodes and uses resistance heat to melt the base metal to form a welded joint by resistance welding. Spot welding is mainly used for thin plate connections, such as aircraft skins, aero-engine fire fume pipes, car cab shells, etc. The welding transformer of the spot welder is a spot welding appliance with only one loop cycle circuit at its secondary level. The upper and lower electrodes and electrode arms are used to transmit not only welding current but also electrical power. Cooling water circuit according to the transformer, electrodes and other components to prevent heating welding, should first pass the cooling water, and then turn on the power switch. The quality of the electrode directly affects the welding process, welding quality and productivity. Electrode materials commonly used purple copper, cadmium bronze, chromium bronze, etc.; determine the shape of the electrode according to the shape of the welded parts. When installing the electrode, pay attention to the upper and lower electrode surfaces to keep parallel; the electrode plane should be kept clean and refurbished with commonly used abrasive cloth or file.
