抄録
Recently, the detailed experimental data about the unidirectional filling of high density polythene in a uniformly elongated flat cavity by Amano (1971) became available. In the present study, the filling length, Λ, or the linear rate of filling, V(≡dΛ/dt), has been related to the filling time, t, by a scheme similar to that proposed by Shibayama (1971) originally for the processes involving amorphous thermoplastics.
The present scheme assumes, along with several other assumptions, YU/Y=Υexp(-mEtU/tE) over a small segment of the cavity, where YU is half the thickness of the molten layer and plays the role of YII (that of the flowing layer) in the original scheme, and Y is half the thickness of the cavity. tU is the time measured from the instant when the flow front passed the segment. Υ, mE and tE are constants. In the outset of the filling, the rate stays higher than predicted, perhaps owing to the constant-rate behavior of the hydraulic system during this period. This condition is different from the constant-pressure one assumed in the prediction. The rate approaches gradually to the prediction. A small discrepancy between the measured and the predicted is possibly due to the errors in fitting a curve to the Λ-t data and in differentiation. Also the applicability of other scheme by Grinblet (1970) has been tested.
