Using capacitor energy storage for spot welding

What is capacitor discharge resistance welding?

Capacitive discharge resistance welding uses large capacitors to store energy for quick release. Figure 1 shows a typical capacitor discharge curve. Capacitive resistance welders have many advantages. Weld nugget formation takes place during the first few milli-seconds.

What is a capacitive welder?

Capacitive welders deliver repeatable welds even during line voltage fluctuations. Spot welding relies on the principle of metal resistivity to heat and fuse metal. A large current is passed through the work piece. Energy is dissipated due to the metal resistance in the form of heat which melts and fuses weld materials. There are two phases to

What is a capacitive discharge welder?

Capacitive discharge welders allow extremely fast energy release with large peak currents. More of the energy goes into weld formation and less into heating surrounding material. The heat affected zone, where the properties of the metal have been changed from rapid heating and cooling, is localized to a small area around the weld spot.

Does a spot welder need a microcontroller?

This spot welder, unlike many available DIY projects, doesn't need a microcontroller to work: the welding pulse is triggered using relay module and a timing capacitor. Welding current is switched with an old recycled industrial thyristor module. Pulse energy can be adjusted with a potentiometer, which changes the voltage of capacitor bank.

Can supercapacitors be used in a spot welder?

Of course It certainly is possible to use supercapacitors in a spot welder, as I saw some existing designs, but they usually have precise pulse control with MOSFETs and microcontrollers, and these supercaps are treated in similar way as batteries. Regular electrolytic capacitors are easier to use without sophisticated pulse control system.

What are the advantages of a capacitive resistance welder?

Capacitive resistance welders have many advantages. Weld nugget formation takes place during the first few milli-seconds. Capacitive discharge welders allow extremely fast energy release with large peak currents. More of the energy goes into weld formation and less into heating surrounding material.