Hopmann / Michaeli Extrusion Dies for Plastics and Rubber

Design and Engineering Computations
4. Auflage 2016
ISBN: 978-1-56990-624-8
Verlag: Hanser Publications
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 470 Seiten

This definitive book provides a comprehensive account of the full range of dies used for extrusion of plastics and elastomers. The distinctive features of the various types of dies are described in detail. Expert advice on the configuration of dies is given, and the possibilities of computer-aided design, as well as its limitations, are demonstrated.

Fundamentals and computational procedures are clearly explained so that no special prior knowledge of the subject is required. The mechanical configuration, handling, and maintenance of extrusion dies are described. Calibration procedures for pipes and profiles are also discussed.

This book was written for plastics engineers who need daily support in their practical work in industry and science, as well as for students preparing for their professional life.

The 4th edition is brought up to date with several important additions, including coverage of multilayer (>15 layer) dies, melt encapsulation, and simulation tools (rheological/thermal CFD simulations).

Autoren/Hrsg.

Hopmann, Christian

Michaeli, Walter

Inhaltsverzeichnis

1;Preface;6
2;Preface to the Third Edition;8
3;Preface to the Second Edition;10
4;Preface to the First Edition;12
5;Contents;14
6;1 Introduction;20
6.1;1.1 Reference of Chapter 1;26
7;2 Properties of Polymeric Melts;28
7.1;2.1 Rheological Behavior;28
7.1.1;2.1.1 Viscous Properties of Melts;29
7.1.1.1;2.1.1.1 Viscosity and Flow Functions;29
7.1.1.2;2.1.1.2 Mathematical Description of the Pseudoplastic Behavior of Melts;31
7.1.1.3;2.1.1.3 Influence of Temperature and Pressure on the Flow Behavior;38
7.1.2;2.1.2 Determination of Viscous Flow Behavior;45
7.1.3;2.1.3 Viscoelastic Properties of Melts;51
7.2;2.2 Thermodynamic Behavior;57
7.2.1;2.2.1 Density;58
7.2.2;2.2.2 Thermal Conductivity;60
7.2.3;2.2.3 Specific Heat Capacity;61
7.2.4;2.2.4 Thermal Diffusivity;62
7.2.5;2.2.5 Specific Enthalpy;62
7.3;2.3 References of Chapter 2;65
8;3 Fundamental Equations for Simple Flows;68
8.1;3.1 Flow through a Pipe;69
8.2;3.2 Flow through a Slit;75
8.3;3.3 Flow through an Annular Gap;79
8.4;3.4 Summary of Simple Equations for Dies;83
8.5;3.5 Phenomenon of Wall Slip;93
8.5.1;3.5.1 Model Considering the Wall Slip;93
8.5.2;3.5.2 Instability in the Flow Function - Melt Fracture;98
8.6;3.5 References of Chapter 3;101
9;4 Computation of Velocity and Temperature Distributions in Extrusion Dies;104
9.1;4.1.1 Continuity Equation;105
9.1.1;4.1.2 Momentum Equations;106
9.1.2;4.1.3 Energy Equation;107
9.2;4.2 Restrictive Assumptions and Boundary Conditions;111
9.3;4.3 Analytical Formulas for Solution of the Conservation Equations;113
9.4;4.4 Numerical Solution of Conservation Equations;119
9.4.1;4.4.1 Finite Difference Method;120
9.4.2;4.4.2 Finite Element Method;123
9.4.3;4.4.3 Comparison of FDM and FEM;128
9.4.4;4.4.4 Examples of Computations of Extrusion Dies;131
9.5;4.5 Consideration of the Viscoelastic Behavior of the Material;145
9.6;4.6 Computation of the Extrudate Swelling;149
9.7;4.7 Methods for Designing and Optimizing Extrusion Dies;155
9.7.1;4.7.1 Industrial Practice for the Design of Extrusion Dies;156
9.7.2;4.7.2 Optimization Parameters;159
9.7.2.1;4.7.2.1 Practical Optimization Objectives;159
9.7.2.2;4.7.2.2 Practical Boundary Conditions and Constraints When Designing Flow Channels;160
9.7.2.3;4.7.2.3 Independent Parameters during Die Optimization;161
9.7.2.4;4.7.2.4 Dependent Parameters during Die Optimization and Their Modeling;161
9.7.3;4.7.3 Optimization Methods;163
9.7.3.1;4.7.3.1 Gradient-Free Optimization Methods;165
9.7.3.2;4.7.3.2 Gradient-Based Optimization Methods;168
9.7.3.3;4.7.3.3 Stochastic Optimization Methods;169
9.7.3.4;4.7.3.4 Evolutionary Methods;169
9.7.3.5;4.7.3.5 Treatment of Boundary Conditions;171
9.7.4;4.7.4 Practical Applications of Optimization Strategies for the Design of Extrusion Dies;173
9.7.4.1;4.7.4.1 Optimization of a Convergent Channel Geometry;173
9.7.4.2;4.7.4.2 Optimization of Profile Dies;175
9.8;4.8 References of Chapter 4;181
10;5 Monoextrusion Dies for Thermoplastics;186
10.1;5.1 Dies with Circular Exit Cross Section;186
10.1.1;5.1.1 Designs and Applications;186
10.1.2;5.1.2 Design;194
10.2;5.2 Dies with Slit Exit Cross Section;199
10.2.1;5.2.1 Designs and Applications;199
10.2.2;5.2.2 Design;206
10.2.2.1;5.2.2.1 T-Manifold;209
10.2.2.2;5.2.2.2 Fishtail Manifold;209
10.2.2.3;5.2.2.3 Coathanger Manifold;211
10.2.2.4;5.2.2.4 Numerical Procedures;222
10.2.2.5;5.2.2.5 Considerations for Clam Shelling;224
10.2.2.6;5.2.2.6 Unconventional Manifolds;225
10.2.2.7;5.2.2.7 Operating Performance of Wide Slit Dies;228
10.3;5.3 Dies with Annular Exit Cross Section;231
10.3.1;5.3.1 Types;232
10.3.1.1;5.3.1.1 Center-Fed Mandrel Support Dies;232
10.3.1.2;5.3.1.2 Screen Pack Dies;236
10.3.1.3;5.3.1.3 Side-Fed Mandrel Dies;237
10.3.1.4;5.3.1.4 Spiral Mandrel Dies;238
10.3.2;5.3.2 Applications;241
10.3.2.1;5.3.2.1 Pipe Dies;241
10.3.2.2;5.3.2.2 Blown Film Dies;242
10.3.2.3;5.3.2.3 Dies for the Extrusion of Parisons for Blow Molding;244
10.3.2.4;5.3.2.4 Coating Dies;251
10.3.3;5.3.3 Design;254
10.3.3.1;5.3.3.1 Center-Fed Mandrel Dies and Screen Pack Dies;254
10.3.3.2;5.3.3.2 Side-Fed Mandrel Dies;258
10.3.3.3;5.3.3.3 Spiral Mandrel Dies;261
10.3.3.4;5.3.3.4 Coating Dies;265
10.4;5.4 Formulas for the Computation of the Pressure Loss in Flow Channel Geometries other than Pipe or Slit;269
10.5;5.5 Dies with Irregular Outlet Geometry (Profile Dies);274
10.5.1;5.5.1 Designs and Applications;274
10.5.2;5.5.2 Design;283
10.6;5.6 Dies for Foamed Semifinished Products;291
10.6.1;5.6.1 Dies for Foamed Films;293
10.6.2;5.6.2 Dies for Foamed Profiles;293
10.7;5.7 Special Dies;295
10.7.1;5.7.1 Dies for Coating of Profiles of Arbitrary Cross Section;295
10.7.2;5.7.2 Dies for the Production of Profiles with Reinforcing Inserts;296
10.7.3;5.7.3 Dies for the Production of Nets;297
10.7.4;5.7.4 Slit Die with Driven Screw for the Production of Slabs;298
10.8;5.8 References of Chapter 5;301
11;6 Coextrusion Dies for Thermoplastics;308
11.1;6.1 Designs;309
11.1.1;6.1.1 Externally Combining Coextrusion Dies;309
11.1.2;6.1.2 Adapter (Feedblock) Dies;310
11.1.3;6.1.3 Multimanifold Dies;313
11.1.4;6.1.4 Layer Multiplication Dies;313
11.2;6.2 Applications;315
11.2.1;6.2.1 Film and Sheet Dies;315
11.2.2;6.2.2 Blown Film Dies;317
11.2.3;6.2.3 Dies for the Extrusion of Parisons for Blow Molding;318
11.3;6.3 Computations of Flow and Design;319
11.3.1;6.3.1 Computation of Simple Multilayer Flow with Constant Viscosity;322
11.3.2;6.3.2 Computation of Coextrusion Flow by the Explicit Finite Difference Method;327
11.3.3;6.3.3 Computation of Velocity and Temperature Fields by the Finite Difference Method;330
11.3.4;6.3.4 Computation of Velocity Fields in Coextrusion Flows by FEM;333
11.4;6.4 Instabilities in Multilayer Flow;335
11.5;6.5 References of Chapter 6;342
12;7 Extrusion Dies for Elastomers;344
12.1;7.1 Design of Dies for the Extrusion of Elastomers;344
12.2;7.2 Fundamentals of Design of Extrusion Dies for Elastomers;346
12.2.1;7.2.1 Thermodynamic Material Data;346
12.2.2;7.2.2 Rheological Material Data;347
12.2.3;7.2.3 Computation of Viscous Pressure Losses;350
12.2.3.1;7.2.3.1 Formulas for Isothermal;350
12.2.3.2;7.2.3.2 Approaches to Nonisothermal Computations;353
12.2.4;7.2.4 Estimation of the Peak Temperatures;354
12.2.5;7.2.5 Consideration of the Elastic Behavior of the Material;355
12.3;7.3 Design of Distributor Dies for Elastomers;356
12.4;7.4 Design of Slotted Disks for Extrusion Dies for Elastomers;358
12.4.1;7.4.1 Computation of Pressure Losses;358
12.4.2;7.4.2 Extrudate Swelling (Die Swell);361
12.4.3;7.4.3 Simplified Estimations for the Design of a Slotted Disk;365
12.5;7.5 References of Chapter 7;373
13;8 Heating of Extrusion Dies;376
13.1;8.1 Types and Applications;377
13.1.1;8.1.1 Heating of Extrusion Dies with Fluids;377
13.1.2;8.1.2 Electrically Heated Extrusion Dies;378
13.1.3;8.1.3 Temperature Control of Extrusion Dies;379
13.2;8.2 Thermal Design;381
13.2.1;8.2.1 Criteria and Degrees of Freedom for Thermal Design;381
13.2.2;8.2.2 Heat Balance of the Extrusion Die;383
13.2.3;8.2.3 Restrictive Assumptions in the Modeling;388
13.2.4;8.2.4 Simulation Methods for Thermal Design;388
13.3;8.3 References of Chapter 8;397
14;9 Mechanical Design of Extrusion Dies;400
14.1;9.1 Mechanical Design of a Breaker Plate;401
14.2;9.2 Mechanical Design of a Die with Axially Symmetrical Flow Channels;406
14.3;9.3 Mechanical Design of a Slit Die;416
14.4;9.4 General Design Rules;420
14.5;9.5 Materials for Extrusion Dies;421
14.6;9.6 References of Chapter 9;428
15;10 Handling, Cleaning, and Maintaining Extrusion Dies;430
15.1;10.1 References of Chapter 10;433
16;11 Calibration of Pipes and Profiles;434
16.1;11.1 Types and Applications;437
16.1.1;11.1.1 Friction Calibration;437
16.1.2;11.1.2 External Calibration with Compressed Air;438
16.1.3;11.1.3 External Calibration with Vacuum;439
16.1.4;11.1.4 Internal Calibration;443
16.1.5;11.1.5 Precision Extrusion Pullforming (the Technoform Process);444
16.1.6;11.1.6 Special Process with Movable Calibrators;445
16.2;11.2 Thermal Design of Calibration Lines;445
16.2.1;11.2.1 Analytical Computational Model;447
16.2.2;11.2.2 Numerical Computational Model;451
16.2.3;11.2.3 Analogy Model;456
16.2.4;11.2.4 Thermal Boundary Conditions and Material Data;459
16.3;11.3 Effect of Cooling on the Quality of the Extrudate;460
16.4;11.4 Mechanical Design of Calibration Lines;461
16.5;11.5 Cooling Dies, Process for Production of Solid Bars;461
16.6;11.6 References of Chapter 11;465
17;Index;468

Leseproben

• Properties of Polymeric Melts
• Fundamental Equations for Simple Flows
• Computation of Velocity and Temperature Distributions in Extrusion Dies
• Monoextrusion Dies for Thermoplastics
• Coextrusion Dies for Thermoplastics
• Extrusion Dies for Elastomers
• Heating of Extrusion Dies
• Mechanical Design of Extrusion Dies
• Handling, Cleaning, and Maintaining Extrusion Dies
• Calibration of Pipes and Profiles

Über Autor(innen)

Hopmann, Christian
Prof. Christian Hopmann is, since 2011, Director of the Institute of Plastics Processing (IKV) in Industry and Craft at RWTH Aachen University, Germany. He studied Mechanical Engineering with a particular focus on Plastics Processing at RWTH Aachen and received his doctoral degree, supervised by Prof. Walter Michaeli, in 2000. In 2005, he started his industrial career at RKW AG Rheinische Kunststoffwerke (today: RKW SE). From January 2010 until April 2011 he was Managing Director of RKW Sweden AB in Helsingborg, Sweden.