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Sunstone CDSP Users Guide
TYPICAL CD WELDING APPLICATIONS
• Cross wires
• Thermocouples
• Strain gauges
• Electronic components
• Thin copper, aluminum, brass, and steel wires and sheets
• Miscellaneous resistive welding applications
• Research and development
After you’ve carefully reviewed the users guide and had a chance to use the welder, you’ll nd that Sunstone
welders are the best ne-spot welders available.
What is Capacitive Discharge Resistance Welding?
Whether you’re a novice hobbyist or experienced industrial welder, you should review the science behind CD
welding. Capacitive discharge resistance welding uses capacitors to store energy for quick release. CD welders,
have many advantages over other welder types:
• Quick energy release for welding highly conductive metals such as copper
• Small heat aected weld zones
• Repeatable energy release independent of line voltage uctuations
• Capable of extremely ne energy adjustment
Weld nugget formation takes place during the rst few milliseconds of the welding process. A CD welder allows
extremely fast energy release with large peak currents; more of the energy goes into weld formation and less
into heating surrounding material. The heat-aected zone, where rapid heating and cooling have changed the
properties of the metal, is localized to a small area around the weld spot. The quick discharge rate of CD weld-
ers also allows electrically and thermally conductive materials, such as copper or aluminum, to be welded. Ca-
pacitive discharge welders deliver repeatable welds even during line voltage uctuations because weld energy
is stored before use.
Weld Formation
Spot welding relies on metal resistivity to heat and fuse metal. A large current is passed through the work-piece
metal. Energy is dissipated due to metal resistance in the form of heat which melts and fuses the weld materials.
The release of energy can be graphed, as shown in Figure 3.1.
There are two phases to the melting process. The welder must overcome both the material contact resistance
and the bulk resistance of the material. As show in Figure 3.2, on a micro-scale, material surfaces are rough and
only contact in a limited number of locations. In the rst few milliseconds of weld formation, the high-resistance
metal bridges melt, allowing other bridges to come into contact to continue the melting process. When all
bridges have fused, the contact resistance is zero. The bulk resistance of the metal then plays the nal role in
the weld formation.
