Dynamics and structure development during the course of spin welding of polyvinylidene fluoride were studied using an instrumented spin welding machine. At least four distinct events were found to occur during the melting sequence that occurs during melting of interface. Wear of asperites, melting as a result of Coulombic friction, appearance of finger-like formations whose long axes aligned in the radial direction and final smearing of these finger-like formations transforming the topography of the interface to fibrillar appearance. In the formation of structural variations in radial and axial directions in the HAZ, the Weissenberg effect was found to play a substantial role.