NONISOTHERMAL MODEL OF GLASS-FIBER DRAWING STABILITY

Draw resonance is caused by a constant speed winder that leads to non- constant axial forces (Schultz, 1984). The well studied isothermal New tonian fiber drawing predicts very modest critical draw ratios (around 20, much less than the typical production draw ratios for glass fiber s of 10(3) - 10(5)). The nonisothermal fiber drawing model presented h ere shows that cooling along the spin line strongly stabilizes the pro cess. However, we show that the conclusion of Shah and Pearson (1972a, b) that nonisothermal Newtonian fiber spinning is unconditionally stab le is based on non-converged numerical results. The choice of viscosit y-temperature correlation function has a strong influence in determini ng the stability of the process. While viscoelasticity generally has a n adverse effect on the stability, low viscoelasticity in the presence of extensional thinning helps to slightly improve the maximum critica l draw ratio.