Capacitor Discharge Resistance Welding

Capacitor Discharge Resistance Welding is a special form of Resistance/ Projection welding in which the welding energy is provided by the release of energy stored from a large capacitor bank. Designed for high-precision, mass production, high capacitive discharge resistance welding solutions are available from T. J. Snow ranging from 1 – 160 kJoules.

Since the CD resistance welding process utilizes stored energy rather than conventional processes which use direct demand on incoming power, the welding times are very short and concentrated, typically in 10 milliseconds or less. The resulting short welding time guarantees that the energy required to spot weld is concentrated in the weld zone, with a minimal if any heat affected zone or changes in the metallurgy of the work piece. Additionally, an upgraded power service to your building is often not needed as the high electrical energy required is not taken directly from the power distribution network but from a bank of capacitors, which stores the energy and recharges between welds.

The CD resistance welding process is ideal for quick and repeatable mass production processes that require tight dimensional tolerances. Capacitor discharge resistance welding is ideal for projection, press-fit and annular ring projections up to 4.5″ in diameter. Low marking welds can be better achieved due to the small heat affected zone and dissimilar metals that can often not be welded using conventional resistance welding can be successfully welded using capacitive discharge resistance welding.

The following video shows both a ring projection and a press fit welding example using capacitor discharge resistance welding.

  • Instantaneous high secondary currents
  • Minimal heat affected zone
  • High operating efficiency
  • Ideal for show surfaces
  • No alteration of work piece metallurgy
  • No surface deformation
  • No spatter
  • No power service upgrades necessary
  • Long electrode life (usually does not require cooling due to low heat input)
  • Quality measures
  • Low equipment maintenance
  • An effective solution for welding dissimilar materials
  • Carbonized steel and hardened steel
  • Monitoring and documentation standard in all models

Capacitor Discharge Resistance Welding is ideal for mass produced products in the automotive, appliance, electrical sectors and more.


Fuel line

Powder metal parts

Seat recliner


Gear box part

Electronic box

Air bag inflator

Fuel pressure distributor



T. J. Snow is a distributor and service provider for Capacitor Discharge Spot Welding Systems available in C-Frame and Portal configurations. All machines are custom built to meet customer requirements. Automation is available for the highest efficiency, see examples below. Please call for information on the process and a suitable machine for your application.


C-Frame Capacitor Discharge Unit

C-Frame Capacitor Discharge Unit

Portal Capacitor Discharge Unit

For more information about Capacitor Discharge Resistance Welding or help sizing a machine for your application, please contact T. J. Snow for assistance.