Comparaison between two designs of experiment using the response surface method in order to optimize the velocity distribution in a coat hanger die
Résumé
Balancing the distribution of flow through a die to achieve a uniform velocity distribution across the die exit is one of the most difficult tasks of extrusion die design. The objective of this paper is to obtain a homogeneous velocities distribution at the die exit. In order to keep the same geometry and avoid design and manufacture of a new die, it seems very important to control the die thermally. For this, we optimize the wall temperature of regulation of a coat hanger die in a heterogeneous way, (i.e. the wall temperature may not be constant in the entire die). The temperature of regulation of the melt enables us to locally control the viscosity, which influences the flows in the various zones. The flow analysis results are then combined with an automatic optimisation algorithm that is based on a response surface methodology and a non linear constraint algorithm SQP with several strategies to provide a new profile of the die wall temperature distributions. Two designs of experiment are used and both results are then compared. Typically, for extrusion die design, the objective function states that the average velocity across the die exit is uniform. Constraints are used to limit and /or to control the pressure drop in the die.
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)
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