Resistance Welding vs Medium-Frequency Welding: Key Differences

Resistance welding and medium-frequency (MF) welding are different welding methods. They differ in frequency, weld quality and application fields.

First, frequency: resistance welding typically runs between about 50–4000 Hz, while MF welding uses a medium-frequency inverter DC power supply. Its welding current has no zero-crossing effect, is unaffected by AC mains frequency, and delivers more stable weld quality. MF welder frequencies are generally also in the 50–4000 Hz range; mainstream MF inverter spot welders on the market are around 1000 Hz.

Second, weld quality: MF welding’s no-zero-crossing current yields relatively stable quality; resistance welding is more affected by low mains frequency, so quality can be less stable with a risk of cold joints. Resistance welding clamps the materials between two electrodes and applies current; resistive heating at the contact surface and nearby zones brings the metal to melting or plastic state to form the joint.

Third, applications: MF welding is often used for electronic components at higher effective process frequency; resistance welding is widely used in automotive manufacturing, metalworking and many other fields.

In summary the differences are: 1. Frequency — resistance welding often 50–4000 Hz; MF welding typically around 1000 Hz for mainstream inverter spot welders. 2. Weld quality — MF is more stable without zero-crossing; resistance welding can be less stable under low mains frequency with cold-joint risk. 3. Applications — MF often for electronics; resistance welding across automotive, metalworking and more.