Spot welding, also known as Resistance Spot Welding, is a traditional joining method where two metal sheets are fused together using heat generated by electrical resistance. Electrodes apply pressure and pass current through the materials at a specific point, melting and bonding them at that location. This process is widely used in automotive manufacturing and other high-volume sheet metal applications due to its speed and simplicity.
Refill Friction Stir Spot Welding (RFSSW) is a newer, solid-phase alternative that joins materials without melting. Instead, a rotating tool generates frictional heat to soften the material at the weld site, then stirs and forges the joint. Unlike Friction Stir Spot Welding, RFSSW doesn’t leave a keyhole or indentation—the material is “refilled” after the weld, creating a flush surface. RFSSW is especially well-suited for lightweight materials like aluminum and is gaining traction in industries that require high-strength, low-distortion, and leak-tight joints.
While both processes are used for point-joining sheet materials, RFSSW offers advantages in applications where traditional spot welding may cause thermal distortion, poor fatigue performance, or challenges with dissimilar materials.