Rotary Spot Resistance Welding
The rotary electrodes and the roll tooling are clearly visible on both sides of the rotary spot welding area.
In resistance spot welding, the material's resistance to electrical current flow creates the heat required to form a molten spot, or nugget, between the two pieces of material. After the current is turned off, forge pressure and hold time to contain the weld until it cools sufficiently, which helps produce a strong metallurgical grain structure within the weld.
Several types of material can be welded with the process, including low- or high-carbon steels and alloy steels. Nonferrous metals, such as aluminum and copper alloys, require some special considerations, as these materials tend to deposit more material on the electrodes; an effective electrode dressing system is a must. Aluminum is especially susceptible to distortion from the heat of the weld process and requires an efficient flood coolant and resizing system. Pure copper is such a good conductor that enough electrical resistance cannot be generated to produce an acceptable weld.
