The working principle of the intermediate frequency resistance welding machine is to use the resistance heat generated when the intermediate frequency current passes through the weld, heat the contact surface of the weld to the melting state, and then apply pressure to connect the welds together. The specific process is as follows:

1. Power conversion and rectification: convert the input three-phase power frequency alternating current (usually 50Hz or 60Hz) into direct current through a bridge rectifier circuit. The purpose of this step is to provide a stable DC power supply for the subsequent inverter links, eliminate the positive and negative alternating characteristics of AC current, and make the current direction single.

Inverter: The rectified DC power passes through an inverter circuit composed of power switching devices (such as IGBTs, etc.), and inverts into an intermediate frequency AC power with a frequency usually between 800-2000Hz. Higher intermediate frequency frequency allows the current to have better penetration and skin effect, can heat the welds more evenly, and facilitate precise control of the welding process.

2. Step-down output: The inversely-reset intermediate frequency alternating current is input to the intermediate frequency transformer, and the voltage is reduced through the intermediate frequency transformer. At the same time, the current is increased to a large current value suitable for welding according to the design and welding needs of the welding machine.

3. Rectification is DC: The intermediate frequency alternating current after being reduced by the intermediate frequency transformer is then converted into DC with very small pulsation. The DC output can avoid heat loss when the AC current crosses zero, making the welding heat more concentrated and stable, which is conducive to improving welding quality and reducing thermal stress.

4. Welding heating: The low voltage and high current DC after the above treatment is applied to the weldment through the electrode. Since there is a certain resistance on the contact surface of the weldment, according to Joule's law (where it is heat, current, resistance, and time), a large amount of heat will be generated when the current passes through the contact surface of the weldment, causing the contact surface of the weldment to heat up quickly to the melting state.

5. Pressure connection: While the contact surface of the weldment is heated to melt, pressure is applied to the electrode through mechanical devices (such as cylinders, etc.) to make the weldment come in close contact in a melting state. As the cooling process progresses, the molten metal solidifies, forming a solid metallurgical bond, thereby achieving welding connection of the welded parts.

Guangzhou Yihui Machinery City is one of the earliest manufacturers in China to develop medium-frequency resistance welding machines, with a stable technical team and design team. The company's independent design of the intermediate frequency resistance welding machine is in the leading position in the industry regardless of function, stability, quality control and accuracy. Resistance butt welding and servo control fully realize the one-stop production of intermediate frequency resistance welding machines. The intermediate frequency resistance welding machine uses imported accessories, which greatly improves the service life of the machine. If you have more questions about medium frequency resistance welding machines, please consult Guangzhou Yihui Machinery.