Draw resonance in isothermal and nonisothermal melt spinning

Abstract

The phenomenon of draw resonance was experimentally observed to examine the effect of spinneret zone in terms of the length-to-diameter ratio of die capillary and melt temperature, as well as the effects of spinning length and heat transfer. The phenomenon was also analyzed for a viscoelastic fluid with power law shear-viscosity and constant shear modulus in case of isothermal melt spinning. As to the effect of spinneret zone, draw resonance took place more severely with decrease in the length-to-diameter ratio of die capillary and melt temperature. It was attributed to the resulting high recoverable elastic strain generated through spinneret zone. In nonisothermal spinning, cooling suppressed the onset of draw resonance, and the interplay between cooling and viscoelastic response resulted in stabilization at two extreme regions of spinning length. The mathematical analysis of isothermal melt spinning provided steady state velocity profile in good agreement with experiment, and predicted the onset of draw resonance including the existence of two extreme stable regions of take-up speed. Isothermal experiment, however, could not confirm the theoretical prediction of the second stable region at high speed, because the molten thread-line could not sustain a high tensile force.