DYNAMICS AND STRUCTURE DEVELOPMENT IN SPIN WELDING OF POLYVINYLIDENE FLUORIDE CYLINDRICAL RODS

Dynamics and structure development during the course of spin welding o f polyvinylidene fluoride were studied using an instrumented spin weld ing 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 fi nger-like formations whose long axes aligned in the radial direction a nd final smearing of these finger-like formations transforming the top ography of the interface to fibrillar appearance. In the formation of structural variations in radial and axial directions in the HAZ, the W eissenberg effect was found to play a substantial role.