Friction Stir Spot Welding (FSSW) & Refill FSSW Calculator
Solid-state spot joining kinematics, tool rotational speed, frictional heat input, and refill sleeve/pin volume balance calculator for aluminum structures.
Process Parameters & Inputs
Calculated Engineering Metrics
Toolpath & Geometry Simulation
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Friction Stir Spot Welding (FSSW) Mechanics: FSSW is a solid-state joining process widely adopted in automotive Body-in-White (BIW) and aerospace skin structures to join lightweight aluminum alloys without melting, eliminating porosity, hot cracking, and spatter. Refill FSSW uses concentric independently actuated sleeve and pin tooling: the sleeve plunges while the pin retracts to store plasticized alloy, then reverses to refill the stir zone, leaving a 100% flush joint with zero exit hole.
Lap Joint Strength & Thermal Equations: Frictional heat generated at the shoulder interface is $Q = \frac{2}{3} \pi \mu P \omega (R_o^3 - R_i^3) t_{\text{dwell}}$. Lap shear tensile strength is proportional to bonded stir nugget area ($\approx \frac{\pi D_s^2}{4}$) and grain refinement in the dynamically recrystallized Stir Zone (SZ).
Vector CAM Robotic Toolpaths: Robotic spot welding paths require vector coordinate arrays with verified clamping standoff clearances ($D_{\text{clamp}} \ge D_s + 6\text{ mm}$) and sheet edge margins ($W_{\text{edge}} \ge 1.5 D_s$) to prevent sheet edge bulging.