melt instability

melt instability

[′melt ‚in·stə′bil·əd·ē]
(mechanics)
Instability of the plastic melt flow through a die.
References in periodicals archive ?
One way of avoiding melt instability could be by reducing the shear rates of the process.
Kynar Flex PPA is a new process aid to improve extrusion of LLDPE, mPE, and PP, eliminating or minimizing the effects of melt instability that can occur during high-shear extrusion.
The technical difficulties include: 1) the melt instability between the two ingredients; 2) the need to instantly adjust the throughput ratio; and 3) the complex design of the conjugated spinnerette.
* Polymer melt viscosity * Elasticity, die swell, extrudate defects * Mechanism of melt instability Flow visualization through a glass barrel
However, in spite of extensive study over more than 40 years, there is still no general understanding of the origin of these types of melt instability. Surface melt fracture (SMF) has been the subject of a number of recent studies (4), while GMF has been investigated rather little recently.