synopsisTwo experimental studies of the melt spinning of fibers have been carried out using low-density polyethylene and polystyrene. First, isothermal spinning experiments were carried out and the relationship between the fiber kinematics and drawdown force was studied. The data were correlated by using the following two methods: (1) the concept of a non-Newtonian elongational viscosity and (2) a nonlinear integral theory of viscoelastic fluids. In the second experiment, the spinline temperature profile of a monofilament fiber being pulled down from a spinneret through stagnant air was measured and the heat transfer coefficient computed. A correlation between the local Nusselt number and a fiber Reynolds number was obtained. An integral boundary layer analysis of forced convection heat transfer from a descending fiber was carried out.