A key parameter of resistance welding is weld pressure or force. The proper and consistent application of force improves the mating of the materials increasing the current paths, reducing the interface resistance, and insuring that any oxide barriers between the workpieces are broken through. Repeatable force control insures repeatable weld quality through consistent electrical contact resistance and consistent heat balance. Force control can also be used to trigger welding energy when a pre-determined force level has been achieved, often called 'force firing.' Optimum welds are achieved when the applied force is precise, repeatable, controlled by time schedule, used to fire the power supply, and regulated both to reduce the initial impact and not to become excessive after the weld. Weld Force control is equally as important as weld energy and time control.
To learn more, read our paper 'Electrode Force Control for Foot and Air Actuated Weld Heads'
And for more information about the resistance welding process read our Fundamentals of Resistance Welding.