Extrusion Dies for Plastics and Rubber

Preface

Preface to the Third Edition

Preface to the Second Edition

Preface to the First Edition

Contents

1 Introduction

1.1 Reference of Chapter 1

2 Properties of Polymeric Melts

2.1 Rheological Behavior

2.1.1 Viscous Properties of Melts

2.1.1.1 Viscosity and Flow Functions

2.1.1.2 Mathematical Description of the Pseudoplastic Behavior of Melts

2.1.1.3 Influence of Temperature and Pressure on the Flow Behavior

2.1.2 Determination of Viscous Flow Behavior

2.1.3 Viscoelastic Properties of Melts

2.2 Thermodynamic Behavior

2.2.1 Density

2.2.2 Thermal Conductivity

2.2.3 Specific Heat Capacity

2.2.4 Thermal Diffusivity

2.2.5 Specific Enthalpy

2.3 References of Chapter 2

3 Fundamental Equations for Simple Flows

3.1 Flow through a Pipe

3.2 Flow through a Slit

3.3 Flow through an Annular Gap

3.4 Summary of Simple Equations for Dies

3.5 Phenomenon of Wall Slip

3.5.1 Model Considering the Wall Slip

3.5.2 Instability in the Flow Function - Melt Fracture

3.5 References of Chapter 3

4 Computation of Velocity and Temperature Distributions in Extrusion Dies

4.1.1 Continuity Equation

4.1.2 Momentum Equations

4.1.3 Energy Equation

4.2 Restrictive Assumptions and Boundary Conditions

4.3 Analytical Formulas for Solution of the Conservation Equations

4.4 Numerical Solution of Conservation Equations

4.4.1 Finite Difference Method

4.4.2 Finite Element Method

4.4.3 Comparison of FDM and FEM

4.4.4 Examples of Computations of Extrusion Dies

4.5 Consideration of the Viscoelastic Behavior of the Material

4.6 Computation of the Extrudate Swelling

4.7 Methods for Designing and Optimizing Extrusion Dies

4.7.1 Industrial Practice for the Design of Extrusion Dies

4.7.2 Optimization Parameters

4.7.2.1 Practical Optimization Objectives

4.7.2.2 Practical Boundary Conditions and Constraints When Designing Flow Channels

4.7.2.3 Independent Parameters during Die Optimization

4.7.2.4 Dependent Parameters during Die Optimization and Their Modeling

4.7.3 Optimization Methods

4.7.3.1 Gradient-Free Optimization Methods

4.7.3.2 Gradient-Based Optimization Methods

4.7.3.3 Stochastic Optimization Methods

4.7.3.4 Evolutionary Methods

4.7.3.5 Treatment of Boundary Conditions

4.7.4 Practical Applications of Optimization Strategies for the Design of Extrusion Dies

4.7.4.1 Optimization of a Convergent Channel Geometry

4.7.4.2 Optimization of Profile Dies

4.8 References of Chapter 4

5 Monoextrusion Dies for Thermoplastics

5.1 Dies with Circular Exit Cross Section

5.1.1 Designs and Applications

5.1.2 Design

5.2 Dies with Slit Exit Cross Section

5.2.1 Designs and Applications

5.2.2 Design

5.2.2.1 T-Manifold

5.2.2.2 Fishtail Manifold

5.2.2.3 Coathanger Manifold

5.2.2.4 Numerical Procedures

5.2.2.5 Considerations for Clam Shelling

5.2.2.6 Unconventional Manifolds

5.2.2.7 Operating Performance of Wide Slit Dies

5.3 Dies with Annular Exit Cross Section

5.3.1 Types

5.3.1.1 Center-Fed Mandrel Support Dies

5.3.1.2 Screen Pack Dies

5.3.1.3 Side-Fed Mandrel Dies

5.3.1.4 Spiral Mandrel Dies

5.3.2 Applications

5.3.2.1 Pipe Dies

5.3.2.2 Blown Film Dies

5.3.2.3 Dies for the Extrusion of Parisons for Blow Molding

5.3.2.4 Coating Dies

5.3.3 Design

5.3.3.1 Center-Fed Mandrel Dies and Screen Pack Dies

5.3.3.2 Side-Fed Mandrel Dies

5.3.3.3 Spiral Mandrel Dies

5.3.3.4 Coating Dies

5.4 Formulas for the Computation of the Pressure Loss in Flow Channel Geometries other than Pipe or Slit

5.5 Dies with Irregular Outlet Geometry (Profile Dies)

5.5.1 Designs and Applications

5.5.2 Design

5.6 Dies for Foamed Semifinished Products

5.6.1 Dies for Foamed Films

5.6.2 Dies for Foamed Profiles

5.7 Special Dies

5.7.1 Dies for Coating of Profiles of Arbitrary Cross Section

5.7.2 Dies for the Production of Profiles with Reinforcing Inserts

5.7.3 Dies for the Production of Nets

5.7.4 Slit Die with Driven Screw for the Production of Slabs

5.8 References of Chapter 5

6 Coextrusion Dies for Thermoplastics

6.1 Designs

6.1.1 Externally Combining Coextrusion Dies

6.1.2 Adapter (Feedblock) Dies

6.1.3 Multimanifold Dies

6.1.4 Layer Multiplication Dies

6.2 Applications

6.2.1 Film and Sheet Dies

6.2.2 Blown Film Dies

6.2.3 Dies for the Extrusion of Parisons for Blow Molding

6.3 Computations of Flow and Design

6.3.1 Computation of Simple Multilayer Flow with Constant Viscosity

6.3.2 Computation of Coextrusion Flow by the Explicit Finite Difference Method

6.3.3 Computation of Velocity and Temperature Fields by the Finite Difference Method

6.3.4 Computation of Velocity Fields in Coextrusion Flows by FEM

6.4 Instabilities in Multilayer Flow

6.5 References of Chapter 6

7 Extrusion Dies for Elastomers

7.1 Design of Dies for the Extrusion of Elastomers

7.2 Fundamentals of Design of Extrusion Dies for Elastomers

7.2.1 Thermodynamic Material Data

7.2.2 Rheological Material Data

7.2.3 Computation of Viscous Pressure Losses

7.2.3.1 Formulas for Isothermal

7.2.3.2 Approaches to Nonisothermal Computations

7.2.4 Estimation of the Peak Temperatures

7.2.5 Consideration of the Elastic Behavior of the Material

7.3 Design of Distributor Dies for Elastomers

7.4 Design of Slotted Disks for Extrusion Dies for Elastomers

7.4.1 Computation of Pressure Losses

7.4.2 Extrudate Swelling (Die Swell)

7.4.3 Simplified Estimations for the Design of a Slotted Disk

7.5 References of Chapter 7

8 Heating of Extrusion Dies

8.1 Types and Applications

8.1.1 Heating of Extrusion Dies with Fluids

8.1.2 Electrically Heated Extrusion Dies

8.1.3 Temperature Control of Extrusion Dies

8.2 Thermal Design

8.2.1 Criteria and Degrees of Freedom for Thermal Design

8.2.2 Heat Balance of the Extrusion Die

8.2.3 Restrictive Assumptions in the Modeling

8.2.4 Simulation Methods for Thermal Design

8.3 References of Chapter 8

9 Mechanical Design of Extrusion Dies

9.1 Mechanical Design of a Breaker Plate

9.2 Mechanical Design of a Die with Axially Symmetrical Flow Channels

9.3 Mechanical Design of a Slit Die

9.4 General Design Rules

9.5 Materials for Extrusion Dies

9.6 References of Chapter 9

10 Handling, Cleaning, and Maintaining Extrusion Dies

10.1 References of Chapter 10

11 Calibration of Pipes and Profiles

11.1 Types and Applications

11.1.1 Friction Calibration

11.1.2 External Calibration with Compressed Air

11.1.3 External Calibration with Vacuum

11.1.4 Internal Calibration

11.1.5 Precision Extrusion Pullforming (the Technoform Process)

11.1.6 Special Process with Movable Calibrators

11.2 Thermal Design of Calibration Lines

11.2.1 Analytical Computational Model

11.2.2 Numerical Computational Model

11.2.3 Analogy Model

11.2.4 Thermal Boundary Conditions and Material Data

11.3 Effect of Cooling on the Quality of the Extrudate

11.4 Mechanical Design of Calibration Lines

11.5 Cooling Dies, Process for Production of Solid Bars

11.6 References of Chapter 11

Index