DN-25 Pneumatic Spot Welder
Pneumatic spot welding machines are divided into universal type (universal type) and special type according to the purpose; according to the number of simultaneous welding points, there are single-point type, double-point type and multi-point type; according to the conductive method, there are single-sided types. Both sides; according to the transmission mode of the pressurizing mechanism, there are pedal, motor-cam, pneumatic, hydraulic, and composite (pneumatic and hydraulic); according to the characteristics of the operation, there are non-automatic and automatic; According to the installation method, there are fixed, mobile or light (suspended); according to the moving direction of the movable electrode (usually the upper electrode) of the welding machine, there are vertical stroke (the electrode moves linearly), circular stroke According to the power supply mode, there are industrial frequency welding machines (using 50 Hz AC power), pulse welding machines (DC pulse welding machines, energy storage welding machines, etc.), and frequency conversion welding machines (such as low frequency welding machines).
When the workpiece and the electrode are constant, the resistance of the workpiece depends on its resistivity. Therefore, resistivity is an important property of the material being welded. Metals with high resistivity have poor conductivity (such as stainless steel). Metals with low resistivity have good conductivity. (Such as aluminum alloy). Therefore, it is difficult to produce heat when spot welding stainless steel, and it is difficult to dissipate heat. It is difficult to produce heat when spot welding aluminum alloy. Million amps). Resistivity depends not only on the type of metal, but also on the heat treatment state, processing method, and temperature of the metal.
In order to ensure the size of the nugget and the strength of the joint, the welding time and the welding current can complement each other within a certain range. In order to obtain a solder joint with a certain strength, high current and short time (strong conditions, also known as hard specifications) can be used, and low current and long time (weak conditions, also known as soft specifications) can be used. The choice between hard and soft specifications depends on the metal's performance, thickness, and power of the welder used. There are upper and lower limits for the current and time required for metals with different properties and thicknesses, whichever is in use.
The electrode pressure has a significant effect on the total resistance R between the two electrodes. With the increase of the electrode pressure, R decreases significantly, but the increase in the welding current is not large, which cannot affect the reduction of heat generation caused by the decrease of R. Therefore, the strength of the solder joint always decreases as the welding pressure increases. The solution is to increase the welding current of the 2D wire bending machine while increasing the welding pressure.