Kinematic waves and draw resonance in film casting process

Transient solutions of the dynamics in film blowing processes

“…The utility of these transient solutions of film blowing process is rather far-reaching in both analysis and synthesis of the system: first, it enables us to confirm the same draw resonance criterion previously developed in fiber spinning and film casting based on the traveling times of kinematic waves [10,11], also applying to film blowing. Second, the sensitivity analysis of assessing the effects of process conditions such as cooling, viscoelasticity of input polymers, and the air amount/pressure inside the bubble, on the behavior of the system can be easily performed with transient solutions as in other extensional deformation processes [12].…”

Stabilization of film casting by an encapsulation extrusion method

“…(1)-(7) have been obtained using a first-order upwind implicit finite difference method to avoid numerical instability problems caused by the fluid viscoelasticity, particularly at high Deborah numbers. It also has been found that the x-t grid of 2000 × 10, 000 mesh points guarantees acceptable accuracy for numerical results in typical viscoelastic cases [7,11,20,21].…”

“…Polymer melts are extruded from a flat die, stretched and cooled by the pulling motion of the chill roll, resulting in film product with frozen-in molecular orientations [1][2][3][4][5][6][7]. The draw ratio is defined between the die and the chill roll, as the ratio of the take-up velocity of the film at the chill roll to its extrusion velocity at the die exit.…”

Nonlinear dynamics and chaotic motion in the isothermal film casting process

“…For the first velocity-controlled drawing regime, constant width 1-D model proposed by Co's group for film casting has been employed (Anturkar and Co, 1988). Even though this model could not portray neck-in phenomenon like varying width 1-D or 2-D model (Silagy et al, 1996;Lee et al, 2001;Shin et al, 2007), it is sufficient to delineate draw resonance instability and chaotic motion which are focused in this study. The dimensionless governing equations for the isothermal film casting with Upper-convected Maxwell (UCM) fluids are as follows.…”