During polymer processing when polymer exits extrusion die there are high deformation and no constraining surfaces to determine the final dimensions of the product. Modelling of these processes is complicated not only by the complex, strongly nonlinear rheology of the melt but also by the crystallization process. This complicates the theoretical description of the processes insomuch that the relations between processing, material and geometry parameters have not been plausibly defined yet. The situation becomes even more complicated due to the phenomenon called die drool (unwanted material accumulation on the die lips) which has not been hitherto fully understood. The main objective of the present project is to derive relations between processing, material and geometry parameters with the aim of optimizing production and determining critical parameters for setting the destabilization phenomenon die drool. |
