A Correlation of the Onset of Draw Resonance Spinline Instability

Abstract

Draw-resonance instability observed in fiber spinning is experimentally examined with an isothermal monofilament spinning setup. Two polypropylene resins are used in this study. An apparent spinline elongation rate is obtained and found to be a key parameter influencing the onset of draw resonance. From dimensional analysis, the critical draw-down ratio is seen to depend on several dimensionless groups. An important one can be expressed by the ratio between the spinline elongation rate (T) and the spinneret extrusion shear rate ( y ) .A dimensionless cr.itical stability contour is constructed in a plot of the critical draw-down ratio versus the ratio of (Tly). This stability contour provides a guideline for stable spinning conditions based on rheologically significant parameters. The validity of this stability contour is confirmed by the critical spinline stability data of the two different polypropylene resins operated at conditions with the same rheological properties.

Frequency Response Analysis of Polymer Melt Spinning

“…In all these cases the increased sensitivity seems to be associated with increasing the viscoelastic relaxation time. Transitions to draw resonance like those described here have been reported in polypropylene spinning by Gupta and Drechsel (1981), Yoo (1987), and Lee (1987).…”