How does resistance welding work?

Subsequent melting and the formation of new bridges allow the weld to be formed. HEAT BALANCE – During resistance welding, part of the heat generated is lost to the surroundings by conduction (heat transfer through solids), convection (heat lost from exposed surfaces by air-cooling), and radiation (does not require a medium).

What is a resistance welding power supply?

The weld current (I) and duration of current (t) are controlled by the resistance welding power supply. The resistance of the workpieces (R) is a function of the weld force and the materials used. The thermal constant “K” can be affected by part geometry, fixturing and weld force.

How does a weld force affect the resistance of a workpiece?

The resistance of the workpieces (R) is a function of the weld force and the materials used. The thermal constant “K” can be affected by part geometry, fixturing and weld force. The bulk and contact resistance values of the workpieces, electrodes, and their interfaces both cause and affect the amount of heat generated.

What is the role of electrodes in resistance welding?

The MATERIALS section (pg. 2) discussed the “rule of opposites” and the criteria for selecting the electrode material. The welding electrodes play three different roles in resistance welding: maintaining uniform current density, concentrating current at welding points, and maintaining thermal balance during welding.

What is a stored energy welding power supply?

The stored energy welding power supply, commonly called a Capacitive Discharge or CD Welder, extracts energy from the power line over a period of time and stores it in welding capacitors. Thus, the effective weld energy is independent of line voltage fluctuations.

How do you choose a resist Ance welding electrode?

The choice of electrode configurations is determined by the geometry of the workpieces, the application, and the desired current path. Opposed (Direct) Welding is the most commonly used type of resist-ance welding. The welding current flows directly from one electrode to the other, through the weldments.