Computer-aided design of extrusion dies for thermoplastics
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
This report presents a survey of the literature on the design of extrusion dies for thermoplastics. The need for scientific die design and the major problem areas are discussed. In the literature survey, the major problems isolated were: 1. Material Properties 2. Die Flow Analysis 3. Flow Instability and Melt Fracture 4. Melt Elasticity. Attention was then confined to Die Flow Analysis. The finite element method was proposed for solving two dimensional flow problems in complex geometrical configurations commonly encountered in polymer extrusions. The two finite element methods adopted used the variational principle in the formulation of the problem. Also, different variational functionals and nodal variables were used. The results of the two methods were successfully compared with finite difference, analytical and existing numerical solutions. The flexibility of the finite element methods makes them very suitable for problems involving complex boundary geometries. It is shown that the finite element method has great potential for use in flow problems, and represents a powerful new tool for the analysis of viscous flows.