This fastener is an externally or internally threaded metal part designed to be fused permanently in place by standard production-welding equipment. Two methods of resistance welding are used:
Projection welding: Heat is localized through embossed or coined projections on the fastener. During the welding process, the projections coalesce with the part surface to form the weld. For best results, a press-type welder with electronic controls is usually recommended. This type of welder gives positive electrode alignment and equalized welding pressures.
Spot welding: The current is directed through the entire area under the electrode tip. Welding is usually performed by a spot welder. This type of welding equipment can satisfactorily weld a number of fastener designs.
Spot welding costs less than projection welding. However, the projection welder is more flexible and permits far greater latitude in design.
