What is Capacitor Discharge Welding (CD welding)?

Capacitor Discharge Welding (CD welding) is a fast form of resistance welding that utilizes capacitors to deliver power to the part. Capacitors are charged with large amounts of energy, which is then rapidly released into the parts within milliseconds.

How does CD welding work?

With CD welding, the main energy is stored in a capacitor arrangement. In application, that energy is discharged through a transformer creating again low voltage – high current power for welding. CD welding does differ from conventional resistance welding in a number of ways(1).

Are electrolytic capacitors a viable alternative for large capacity CD welding systems?

Electrolytic capacitors (E-caps) offer a potential alternative for large capacity CD welding systems. E-caps incorporate an electrolyte impregnated into a separator. The separator is then sandwiched between anodic and cathodic foils. A dielectric is also used to prevent direct contact of the foils with the electrolyte.

What are energy storage capacitors?

Capacitors exhibit exceptional power density, a vast operational temperature range, remarkable reliability, lightweight construction, and high efficiency, making them extensively utilized in the realm of energy storage. There exist two primary categories of energy storage capacitors: dielectric capacitors and supercapacitors.

What is the difference between a transformer and a capacitor?

The transformer arrangement produces low voltage, high current power that is suitable for resistance welding. With CD welding, the main energy is stored in a capacitor arrangement. In application, that energy is discharged through a transformer creating again low voltage – high current power for welding.

How does a capacitor 'C' work?

The capacitor ‘C’ is charged to about 3,000 V from a controlled rectifier. The capacitor is connected to the primary of welding transformer through the switch and will discharge. This discharge will produce high transient current in the secondary to join the two metal pieces.