The energy equation for the furnace drawing of fused silica rods is formulated in such a way that we are able to predict the temperature distribution and therefore the viscosity distribution along the neck-down region. From this and the equation of motion describing the nature of the flow field the neck-down shape is predicted. Experimentally the neck-down shape and the elongation viscosity distribution are determined and compared with predicted values. The above solutions also supply other information regarding the dynamic variables such as the local stress, the velocity field, and the required drawing tension.
© 1977 Optical Society of AmericaPDF Article