Stability of Film Casting

Anturkar and Co (1988) studied the effects of viscoelasticity on the stability of the film-casting process in a similar fashion to that of Fisher and Denn (1976). The constitutive equation used in their theoretical analysis is the UCM (Eqs. 3.40 and 3.41) with the Carreau viscosity function (Eq. 2.8 with jjco = 0) ()/) = jo (l + which 

Note that the draw ratio. Dr, in this case can be written as 

Equation 9.126 is similar to Eq. 9.26 of the fiber-spinning case, and in general the film-casting process can be considered the two-dimensional counterpart of the fiber-spinning process (see also Problem 9A.4). 

FIGURE 9.18 Critical draw ratio, Dr, as a function of the viscoelastic parameter Ao(2A,) and the power-law index n, for the film-casting process. (Reprinted by permission of the publisher from Anturkar and Co, 1988.) 

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