Welding system and method

摘要

A method of resistance spot welding is disclosed. The method includes providing a first metallic workpiece having a primary surface and a second metallic workpiece having a secondary surface. The method also includes positioning the primary surface into physical contact with a first electrode and a second electrode into physical contact with the secondary surface. The second electrode includes a secondary actuator. The method also includes measuring contact force between the first electrode and the second electrode, and initiating a current through the first electrode when the contact force reaches a preselected force value. The method also includes forming a weld nugget in at least the second workpiece and a depression in the primary surface of the first workpiece, and controlling the location of the weld nugget by using two different classes of electrodes. The depression in the primary surface is substantially undetectable by a visual examination. A resistance spot welding system is also disclosed. The system includes a fast follow-up electrode of one RWMA class mounted to one end of a pivot arm for squeezing a primary workpiece and a secondary workpiece together and for following the surface of the secondary workpiece as the weld is formed. A stationary electrode of another RWMA class is positioned opposite the fast follow-up electrode. A sensor is coupled to the stationary electrode for directly measuring the contact force between the fast follow-up electrode and the stationary electrode. A measuring instrument for measuring a depression formed in the primary surface.