Pressing applications are very similar to simple squeeze flows. Typical time scales for pressing applications are rather short: they range from on the order of a tenth of a second up to a few seconds. With the exception of rheometric measurements, they depend more or less on the geometrical size of the melt sample. Hence, starting from an initial rest state, stresses develop within that time interval. Although the rate of deformation can be large, deformations remain moderate. Consequently, dynamic or linear measurements alone provide a good characterization of the melt for pressing.

The selected spectrum of the rheological model may, of course, involve very short times and very long times. Actually, very short time scales (that is, those smaller than the typical process time) can be replaced by a purely Newtonian contribution. Similarly, long times (that is, much longer than the process time) probably do not have the opportunity to develop their own contribution to the stress, and can be omitted if necessary.