Spinning instabilities, relation

Matsuo, et. al(l ) also published an interesting table (Figure 17) that relates several commonly observed spinning instabilities which should be useful to any spinner. In their paper, they are not clear how this table was developed, but it is interesting to note that they show the relevant calculable variables. It is not unreasonable that one can obtain stability information from a steady-state model. For example, Kase(9) develops a linearized transient model which can be expressed in terms of time and position-dependent deviation variables and position-dependent but time-independent parameters derived from the steady-state solution. Thus, the stability of the system of deviation equations is determined solely by the values of functions of the steady-state solution only. 

Figure 17 Relation of Spinning Instabilities to Process Parameters (M)...

In this presentation, I shall show that high-resolution Fourier-transform infrared spectroscopy is a useful tool for studying (i) rare-earth containing isulators, low-dimensional magnetics, in particular, and (ii) quasi-one dimensional magnetic systems with the spin-Peierls and related instabilities. 

There are two unique aspects to the water-quenching of polypropylene. As with other thermoplastic melts, this material exhibits draw resonance under certain spinning conditions. Polypropylene apparently is more susceptible to this phenomenon than many other materials. Under certain conditions, the filament will be uniform all along its length. If the take-up speed is increased, a critical value of speed will be reached when the filament diameter begins to oscillate in a regular manner. The amplitude of diameter oscillation can reach 10-50% of the nominal diameter of the filament. The instability seems to be related to a critical value of the ratio Ft/ Fe, where Fj is take-up velocity and Fe is extrusion velocity. The critical ratio is affected by resin properties, extrusion temperature, filament nominal diameter, distance between spinneret and bath, and perhaps other process parameters. 

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