Basic Configuration of Resistance Welder and Role of Each Part

Resistance welder sandwiches an object to be welded by the welding electrodes, andapplies electric current while applying pressure.

  • Welding Power Supply: It controls the magnitude, time and waveform of electric current
  • Welding Transformer: It converts the electric current from the power supply to a larger current
  • Welding Head: It controls the pressure to be applied
  • Welding Electrode: It contacts the object to be welded to apply pressure and electric current
  • In addition to the above, we have various monitors which measure electric current or applied pressure.

Resistance Welding Model, Temperature Distribution at the Welding

Welding Power Supply: Control Method

An appropriate welding power supply must be selected based on the material or shape of the object to be welded and the required welding quality. There are three different types in our welding power supplies based on the type of control of the welding current, and each type is selected in a way to best demonstrate its characteristic in welding.


Basic system Welding Current Wave Form Feature
Inverter Type

AC current is rectified into DC current.
Because of high frequency,
heat efficiency is good and suitable for precision welding.
Furthermore, stable welding quality can be expected
because of the electric current and voltage feedback control.
As high speed repetitive welding can be made,
it is suitable for use in automated systems.
Transistor Type

Electric current is directly controlled by a transistor.
Because the control speed is fast and the waveform can be controlled,
it is suitable to ultra high precision welding of
very small components or extremely ne wires.
Stable welding quality can be obtained by
the electric current and voltage feedback control.

Electric is charged into a capacitor and discharged at once.
Because a large current can be applied,
it is used for material which has good heat dissipation
characteristic and difficult to weld, such as aluminum or copper.
Furthermore, because of the short welding duration,
heat impact is minimized, and as a result, it is suitable for welding of small components.
Single Phase(AC)Type

Welding Current is controlled by a thyristor.
Because the welding duration can be mode long,
it has a broad application, and it is suitable for
a material which is relatively easy to weld, such as iron.

Welding Head & Electrode

How the electrode contacts the object to be welded (how to apply the current) is determined by the shape or structure of the object. Furthermore, shape and material of the electrode and the applied pressure are also important factors in resistance welding.

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