Capacitative Discharge (CD) Welding Process

The Capacitor Discharge (CD) Stud Welding Method

Capacitor Discharge (CD) stud welding, using very short weld times, permits the welding of small-diameter studs to thin, lightweight materials. The weld cycle can be completed in 0.01 seconds on material as thin as 0.020″ (0.5mm). These fast weld times minimize heat buildup, resulting in welds with very little distortion, discoloration, or burning. Therefore, CD stud welding is often used when appearance is a critical product feature.

CD stud welding uses a capacitor storage system to produce a rapid electrical discharge, stud welding guns, and fasteners. No ferrules or flux are needed. The CD stud welding method, used mainly for welding mild steel, stainless steel, and aluminum studs, includes two primary techniques: Contact and Gap. Both require a specially designed stud with a projection, or ignition tip, on its weld end. This tip provides accurate welding time control with precise repeatability.

For more on CD Stud Welding, see our White Paper.

CD Stud Welding Initial Contact Process Diagram

Capacitive Discharge Initial Contact Process Diagram

CD Stud Welding Initial Gap Method

Capacitive Discharge Initial Gap Process Diagram

CD Stud Welding Advantages

CD stud welding creates high integrity welds even on thin gauge materials. Additionally, it allows the welding of dissimilar metals because the weld penetration is so slight that metallurgical problems are prevented. The quality, productivity, and cost advantages of CD stud welding include:

Improved Quality

Attractive appearance with minimal burn — Often important in cosmetic applications, CD stud welding offers appealing one-sided welds with no reverse-side dimples.

Strength in lightweight applications — On very lightweight material that would be compromised when using other fastening processes, CD stud welding creates a strong, high quality bond.

Minimal backside marking — CD stud welding allows backsides to be prepainted without damage to the paint.


Fast process — With its extremely short weld times, CD stud welding substantially increases productivity.

Fewer assembly steps — Like Arc stud welding, CD stud welding eliminates punching, drilling, tapping, and riveting.

Economic Advantages

Labor savings — As in Arc stud welding, the CD stud welding process saves significant costs by eliminating through-hole preparation.

Fabrication savings — Often, an expensive, oddly-shaped piece can be duplicated inexpensively by welding several studs to a simple stock shape to form a metal fabrication.