Admin مدير المنتدى
عدد المساهمات : 19002 التقييم : 35506 تاريخ التسجيل : 01/07/2009 الدولة : مصر العمل : مدير منتدى هندسة الإنتاج والتصميم الميكانيكى
| موضوع: كتاب The Mould Design Guide السبت 07 مايو 2022, 6:14 am | |
|
أخواني في الله أحضرت لكم كتاب The Mould Design Guide Peter Jones
و المحتوى كما يلي :
Contents 1 Introduction . 1 2 The Injection Moulding Process 5 2.1 Background 5 2.2 Machine Design 6 2.2.1 Machine Base Unit 6 2.2.2 Clamp Unit . 6 2.2.3 Mould Height . 6 2.2.4 Daylight 7 2.2.5 Distance Between Tie Bars . 8 2.2.6 Clamping Mechanisms 9 2.2.7 The Injection Unit . 13 2.3 Theoretical Mould Locking Force 19 2.4 The Moulding Cycle . 20 2.4.1 Mould Closing Phase . 20 2.4.2 Mould Protection Phase 20 2.4.3 Injection (Mould Filling) Phase 20 2.4.4 Holding Time and Pressurising Phase . 20 2.4.5 Cooling and Refill Phase 21 2.4.6 Screw Back Phase 21 2.4.7 Mould Open Phase 21 2.4.8 Ejection Phase . 22Mould Design Guide 3 Plastics Materials 23 3.1 Types of Plastics Materials 23 3.2 Definition of Plastics . 23 3.3 The Nature of Plastics Materials . 24 3.4 Monomers, Polymerisation and Polymers 25 3.5 Classification of Plastics 26 3.5.1 Thermosets and Thermoplastics 26 3.5.2 Homopolymers, Copolymers and Polymer Blends (Alloys) . 27 3.5.3 Amorphous and Semicrystalline Thermoplastics 29 3.6 Melting and Solidification . 30 3.7 Shrinkage . 31 3.8 Engineering and Commodity Plastics . 32 3.8.1 Engineering Plastics . 32 3.8.2 Commodity Plastics 32 3.9 Material Additives 33 3.10 Flow Properties of Thermoplastic Materials . 35 3.11 Variable Molecular Weight . 35 3.12 Melt Flow Index (MFI) . 36 3.13 Reprocessed Material 37 3.14 Polymer Molecules 37 3.15 Material Names and Abbreviations . 37 3.16 Material Applications . 40Contents iii 3.17 The Behaviour of Thermoplastics During the Injection Moulding Process 41 3.17.1 Pretreatment of Materials Before Injection Moulding . 41 3.17.2 Reprocessed Materials . 41 3.17.3 Colouring Materials 41 3.17.4 Additives 41 3.17.5 Material Drying 42 3.17.6 Plasticising or Melting . 43 3.17.7 Measurement of Melt Temperature . 44 3.17.8 Degradation of Materials During Plasticising . 44 3.17.9 Selecting the Optimum Melt Temperature 45 3.17.10 The Effect of Screw Rotational Speed and Back Pressure 45 3.17.11 Flow Characteristics of the Melt During the Injection Phase . 46 3.17.12 Selection of Injection Speed . 46 3.18 Initial Cavity Filling Phase . 48 3.19 Cavity Holding Pressure Phase 49 3.20 Gate Freeze-off Phase 49 3.21 Melt Compressibility and Shrinkage 49 3.22 Sinks and Voids 50 3.23 Weld Lines and Meld Lines . 53 3.24 Cooling and Solidification of the Melt . 54 4 Good Design Practice 55 4.1 Predesign Analysis 56 4.2 Reading General Arrangement Diagrams (GA) 56 4.3 Understanding Toolmaking Concepts 57Mould Design Guide iv 4.4 Observing Mould Tools 58 4.5 Summary of Good Design Practice . 58 5 Design Checklist . 59 5.1 Predesign Checklist . 59 5.2 Original Estimate Details 60 5.3 Component Drawing 60 5.4 Component Geometry . 60 5.5 Component Material . 61 5.6 Quantity Required 61 5.7 Component Function 61 5.8 Component Tolerances . 62 5.9 Number of Impressions . 62 5.10 Gating Method . 62 5.11 Ejection Method . 63 5.12 Component Aesthetics 63 6 Determining the Right Number of Impressions 65 6.1 Quality Versus Quantity . 66 6.2 Appearance . 66 6.3 Part Geometry 67 6.4 Drawing Tolerances 67 6.5 Discussion 67 6.6 More Cavities = Less Control 68 6.7 Summary 70Contents v 7 Step-by-Step Design 71 7.1 Predesign Requirements 71 7.2 Golden Rules 71 7.3 Step-by-Step Design 72 7.4 Design Example 72 7.4.1 STEP 1: The Split Line . 73 7.4.2 STEP 2: Gating . 75 7.4.3 STEP 3: Ejection 75 7.4.4 STEP 4: Cavity Inserts . 76 7.4.5 STEP 5: Venting 78 7.4.6 STEP 6: Water Cooling 79 7.4.7 STEP 7: Impression Centres . 80 7.4.8 STEP 8: Mould Layout 81 7.4.9 STEP 9: Main Sectional View 82 8 Mouldmaking . 83 8.1 Discussion 83 8.2 General Mould Requirements 83 8.2.1 Mould Materials . 83 8.2.2 Alloy Steels . 84 8.2.3 Mild Steel . 84 8.2.4 Beryllium-Copper 84 8.3 General Construction 85 8.3.1 Cavity Construction 85 8.3.2 Turning 86Mould Design Guide vi 8.3.3 Milling . 86 8.3.4 Grinding . 87 8.3.5 Fabrication . 88 8.3.6 Standard Electrodischarge Machining (EDM) 89 8.3.7 Wire Electrodischarge Machining 91 8.3.8 Cold Hobbing . 92 8.3.9 Beryllium-Copper 93 8.3.10 Electroforming 93 8.3.11 Cavity Corrosion and Erosion . 95 8.3.12 Gassing and Burning . 95 8.4 Differential Shrinkage . 96 8.5 Maximum Metal Conditions . 97 8.6 Example . 97 9 Two-Plate Mould Tools 99 9.1 Design Details . 99 9.1.1 Locating or Register Ring .101 9.1.2 Top Plate .101 9.1.3 Split Line .102 9.1.4 Cavity Insert 102 9.1.5 Front Cavity Plate 102 9.1.6 Rear Cavity Plate .102 9.1.7 Cavity Support Plate 103 9.1.8 Ejection System 103 9.1.9 Ejection Gap 104Contents vii 9.1.10 Support Blocks .104 9.1.11 Guide Pillar 104 9.1.12 Return Pins 104 9.1.13 Fine Tuning the Mould Tool 104 9.1.14 Clearances .106 9.1.15 Bushes .106 9.1.16 Screws .106 9.1.17 Support Pillars .106 9.1.18 Taper Threads .107 9.1.19 Stand-off Buttons .107 9.1.20 Chamfers and Radii .107 9.1.21 Guide Bushes .107 10 Ejection Systems 109 10.1 Requirements .109 10.1.1 Part Geometry 109 10.1.2 Draft Angles 109 10.1.3 Tolerances .110 10.1.4 Material .110 10.1.5 Gating .111 10.1.6 Ejection Balance .112 10.1.7 Machine Specifications .113 10.1.8 Mould Opening Stroke .113 10.1.9 Machine Ejection Features 113 10.1.10 Movement Control Features .114 10.1.11 Component Finish Requirements 114Mould Design Guide viii 10.2 Ejection Methods .114 10.2.1 Ejector Pins and Blades .114 10.2.2 Sleeve Ejectors 116 10.2.3 Stripper Plate Ejection 117 10.2.4 Valve Ejection 118 10.2.5 Ejection Forces .119 10.3 Ejection Force Calculation .120 10.4 Formulae .120 10.4.1 Example 121 10.5 Ejection Assembly Actuation 122 10.5.1 Mechanical Ejection .122 10.5.2 Hydraulic Ejection .125 10.5.3 Pneumatic Ejection .126 10.5.4 Hybrid Ejection Systems .126 10.5.5 Double Ejection .129 10.6 Unsatisfactory Systems .132 11 Mould Temperature Control 133 11.1 Discussion .133 11.2 Heat Transfer Fluids 134 11.2.1 Water 134 11.2.2 Heat Transfer Oil 134 11.3 Chillers 135 11.4 Temperature Controllers 135 11.5 Cooling Channels 135 11.5.1 Core Cooling .137Contents ix 11.6 Cavity Cooling .145 11.7 Circuit Efficiency .148 11.7.1 Series Cooling 148 11.7.2 Parallel Cooling .149 11.8 Beryllium-Copper Cores and Cavities .150 11.9 Factors Affecting the Cooling Cycle 150 11.9.1 Part Geometry 151 11.9.2 Wall Sections .151 11.9.3 Moulding Material .151 11.9.4 Influence of the Gate and Runner 152 11.9.5 The Mould Material .152 11.10 Mould Temperature Control 152 11.11 Cooling Efficiency 153 11.11.1 Cavity Material and Construction .153 11.11.2 Channel Geometry .154 11.11.3 Number of Channels Required .154 11.11.4 Rate of Coolant Flow .154 11.12 Coolants 155 11.12.1 Thermal Conductance of Metals .155 11.13 Cooling Calculations 155 11.13.1 Specific Heat 155 11.14 Pulsed Mould Cooling 161 11.14.1 Selective Pulsed Cooling .162 11.15 Mould Cooling Variables .163 11.16 Summary .163Mould Design Guide x 12 Undercut Injection Mould Tools 165 12.1 Introduction 165 12.1.1 Undercut Components .167 12.1.2 Basic Undercut Mould Designs .168 12.1.3 Loose Inserts 168 12.1.4 Moulding in Splits 170 12.1.5 Straight Angle Dowels 170 12.2 Key Design Features .172 12.2.1 Example 173 12.3 Offset Angle Dowels 175 12.3.1 Key Design Features .177 12.3.2 To Establish Point P .177 12.4 Use of Side Cores .178 12.4.1 Discussion .178 12.5 Angled Lift Splits .179 12.5.1 Discussion .179 12.5.2 Description of Operation 181 12.5.3 Key Design Features .181 12.5.4 Formulae .181 12.6 Form Pins 182 12.6.1 Discussion .182 12.6.2 Straight Action Form Pins .182 12.6.3 Key Design Features .183 12.6.4 Angled Form Pins .184 12.6.5 Angled Action Form Pin .185Contents xi 12.6.6 Description of Operation 186 12.6.7 Key Design Features .186 12.6.8 Description of Operation 188 12.6.9 Key Design Features .188 12.7 Nonstandard Side Core Designs .188 12.7.1 Undercuts at Angle to Tool Axis .189 12.7.2 Description of Operation 189 12.7.3 Key Design Features .190 12.8 Curved Undercuts 190 12.8.1 Description of Operation 190 12.8.2 Key Design Features .192 12.9 Radial Undercuts .192 12.9.1 Description of Operation 195 12.9.2 Key Design Features .195 12.10 Undercuts on Helical Gears and Pump Impellers .196 12.11 Normal Ejection Techniques 196 12.11.1 Form of Undercut .197 12.11.2 Component Material 198 12.11.3 Satisfactory Materials .198 12.11.4 Unsatisfactory Materials .198 12.12 Special Ejection Designs .199 12.12.1 Splitting the Component .200 12.12.2 Moulding in One Piece .202 12.12.3 Helical Ejection 202Mould Design Guide xii 13 Automatic Unscrewing Mould Tool Design 205 13.1 Introduction 205 13.2 Injection Moulding Thread Forms 206 13.3 Thread Geometry 207 13.3.1 Parallel Threads .207 13.3.2 Number of Starts 207 13.3.3 Thread Form .208 13.3.4 Taper Threads .213 13.3.5 British Standard Pipe Thread 214 13.3.6 Jointing Threads 214 13.3.7 Longscrew Threads 214 13.3.8 Moulded Thread Forms .216 13.4 Thread Shrinkage Compensation 217 13.4.1 Discussion .217 13.4.2 The Effect of Incorrect Shrinkage on Thread Forms 217 13.4.3 Pitch Inaccuracy .218 13.4.4 Thread Form Inaccuracy 218 13.4.5 Inaccurate Thread Diameters 218 13.5 Application of Shrinkage Allowance on Thread Forms 218 13.5.1 Shrinkage Formulae .219 13.6 Injection Moulding Considerations .220 13.6.1 Moulding-related Problems 220 13.6.2 Injection Pressure .220 13.6.3 Injection Speed .220 13.6.4 Unscrewing Speed 220Contents xiii 13.6.5 Ejection Speed 220 13.6.6 Operating Window 221 13.6.7 Tool Temperature Control .221 13.7 Basic Screw Thread Mould Designs 222 13.7.1 Split Tooling 222 13.7.2 Thread Jumping .223 13.7.3 Collapsible Coring .224 13.7.4 Operation of Multisegment Cores .227 13.8 Rotary Unscrewing 227 13.8.1 Collapsible Coring Details 228 13.9 Types of Collapsible Core 228 13.9.1 Two-segment Core Details .229 13.9.2 Multisegment Collapsible Cores .230 13.10 Using Silicone Rubber Sleeve Cores 231 13.10.1 Advantages 231 13.10.2 Disadvantages 232 13.11 Core Unscrewing .234 13.11.1 Fixed Core Systems 234 13.11.2 Cavity in Moving Half .234 13.11.3 Cavity in Fixed Half .235 13.11.4 Key Design Features of Figure 13.18 238 13.12 Anti-Rotation Keying .239 13.12.1 Base Key Geometry 239 13.13 Moving Core Systems .240 13.13.1 Key Design Features .241Mould Design Guide xiv 13.14 Cavity Rotation .242 13.14.1 Key Design Features .244 13.14.2 Guidelines 245 13.15 Two-thread Unscrewing Designs 245 13.15.1 Discussion .245 13.15.2 Key Design Features for Two External Threads .245 13.15.3 Operation 247 13.15.4 Key Design Features .249 13.15.5 Operation 250 13.16 Gearing Geometry .250 13.16.1 Introduction .250 13.16.2 Basic Spur Gear Definitions 252 13.16.3 Basic Spur Gear Formulae 253 13.16.4 Conversion Between ISO and Imperial Systems .253 13.16.5 Example Gear Calculations (ISO) .253 13.16.6 Guidelines for Gear Selection (ISO) .255 13.16.7 Guidelines for Gear Train Design (ISO) 255 13.17 General Mould Design Guide for Threads 256 13.17.1 Observation .256 13.17.2 Stage 1 .256 13.17.3 Stage 2 .257 13.17.4 Stage 3 .258 13.17.5 Stage 4 .259 13.17.6 Stage 5 .259Contents xv 13.18 Driving Systems .260 13.18.1 Rack-and-Pinion Systems .260 13.18.2 Opening Movement of Mould Tool 260 13.18.3 Actuation by Cylinder 261 13.18.4 Pneumatic Motors 263 13.18.5 Hydraulic Motors 263 13.18.6 Electric Motors 265 13.18.7 Clutches and Rotation Control .265 13.18.8 Using Clutches .266 13.18.9 Using Stepper Motors .267 13.18.10 Using Torque Limiters 268 13.19 Special Designs 269 13.20 Commercial Unscrewing Systems 270 14 Multiplate Tool Systems 271 14.1 Three-Plate Tools 271 14.1.1 Three-Plate Tool Operation .273 14.2 Multiplate Undercut Tools .279 14.2.1 Sequential Opening 281 14.3 Stack Moulds .285 15 Runnerless Moulding .291 15.1 Sprueless Moulding 291 15.1.1 Basic Antechamber Type 291 15.1.2 Heated Hot Sprue Bushes .293 15.1.3 Summary .297Mould Design Guide xvi 15.2 Insulated Runner Systems .298 15.2.1 Insulated 298 15.2.2 Semi-insulated 299 15.3 Full Hot Runner Systems 300 15.3.1 Advantages Over Cold Runner Moulds .300 15.3.2 Nozzles and Gate Bushes 305 15.3.3 Open Gate Nozzles 305 15.3.4 Spring-Operated Needle Nozzle 307 15.3.5 Hydraulically Operated Needle Valve Nozzle 308 15.3.6 Multipoint Gating 309 15.3.7 Summary .311 15.4 Heating .311 15.4.1 Band Heaters .311 15.4.2 Coil Heaters .312 15.4.3 Cartridge Heaters .312 15.4.4 Tubular Heaters .312 15.4.5 Integral Heating .313 15.4.6 Heat Pipes 313 15.5 Temperature Control in Manifolds .313 15.5.1 Closed-Loop Control .314 15.5.2 Open-Loop Control .314 15.5.3 Other Factors .314 15.6 Gating .315 15.6.1 Pin and Edge Gating .315 15.6.2 Valve Gating 316 15.6.3 Thermal Sealing .316Contents xvii 15.7 Thermal Expansion 317 15.8 Manifold/Nozzle Interface 318 15.8.1 Nozzle–Mould Interface .318 15.8.2 Heating Capacity Requirements 318 15.8.3 Wattage Density .319 15.8.4 Manifold Heat-Up Time .320 16 Mould Materials 321 16.1 Introduction 321 16.2 Selecting the Material for the Application .322 16.3 Materials Characteristics 323 16.3.1 Steel .323 16.3.2 Plate Steel 324 16.3.3 Cast Steel .326 16.3.4 Nonferrous Materials .329 16.3.5 Aluminium Alloys 330 16.3.6 Zinc Alloys 332 16.3.7 Beryllium–Copper Alloys .332 16.3.8 Bismuth–Tin Alloys .334 16.3.9 Epoxy Resin .335 16.4 Heat Treatment .335 16.4.1 Through-Hardening .336 16.4.2 Pretoughening 338 16.4.3 Carburising or Case Hardening 338 16.4.4 Nitriding 339 16.4.5 Tuftriding 340Mould Design Guide xviii 16.5 Mould Finishing 340 16.5.1 Polishing 341 16.5.2 Chromium Plating 341 16.5.3 Photochemical Etching .341 16.5.4 EDM Finishes 342 16.5.5 Bead Blasting .342 16.5.6 Vapour Blasting .342 16.6 Mould Maintenance .343 17 Runner and Gate Design 345 17.1 The Feed System 345 17.1.1 The Sprue 346 17.1.2 Cold Slug Well .346 17.1.3 Runner Design .347 17.1.4 Runner System Design Rules 350 17.2 Calculating the Runner Length .352 17.2.1 Example 353 17.3 Gate Design .355 17.3.1 Manually Trimmed Gates 360 17.3.2 Automatically Trimmed Gates 360 17.3.3 Gating Design Rules .362 17.3.4 Computer Simulations of Gate Designs .363 17.3.5 Number and Location of Gates .363 17.3.6 Gate Sizing .365 17.3.7 Example 366Contents xix 17.3.8 Gate Land Length 367 17.3.9 Gate Diameter 367 17.4 Establishing the Correct Gate Size 369 17.4.1 Computer Analysis .370 17.4.2 Empirical Analysis .370 18 Standard Mould Parts 373 18.1 Standard Parts Available 373 18.1.1 Mould Base Units .374 18.1.2 Mould Plates 374 18.1.3 Location and Alignment Components .374 18.1.4 Ejection Components .374 18.1.5 Feed Systems 374 18.1.6 Cooling Components .375 18.1.7 Unscrewing Components 375 18.1.8 Miscellaneous 375 18.2 Mould Tool Designing Using Standard Parts .375 18.3 Toolmaking Using Standard Parts 376 18.4 Summary .378 19 Deflection and Stress in Mould Components .379 19.1 Discussion .379 19.1.1 Competition .380 19.1.2 Energy Costs 380 19.1.3 Breakages 380 19.1.4 Deflection 381Mould Design Guide xx 19.2 Force and Stress .381 19.2.1 Definitions of Forces 381 19.2.1.2 Compressive Force .383 19.3 Stress .384 19.4 Strain 384 19.5 Stress–Strain Graph .385 19.5.1 Young’s Modulus of Elasticity 385 19.5.2 Limit of Proportionality .386 19.5.3 The Elastic Limit 386 19.5.4 Yield Stress 386 19.5.5 Tensile Strength .386 19.6 Factor of Safety (FOS) 386 19.6.1 Brittle materials .387 19.6.2 Ductile materials 387 19.7 Poisson’s Ratio 388 19.7.1 Example 389 19.8 Temperature Stresses .390 19.8.1 Example 390 19.9 Beam Theory .390 19.9.1 Beam Models .392 19.10 Bending Moments 393 19.10.1 Neutral Axis 393 19.10.2 Second Moment of Area .394 19.11 Bending Formula .396 19.12 Section Modulus 396Contents xxi 19.13 Deflection of Beams .397 19.14 Analysing Mould Tools 397 19.14.1 Two-Plate Example 397 19.14.2 Split Tool Example 400 19.14.3 Analysing Core Pins .403 19.15 Summary .405 20 Fatigue 407 20.1 Observations .407 20.2 Facts on Fatigue .408 20.3 Calculating Shut-off Areas .410 20.3.1 Example 412 20.4 Factors Affecting Fatigue Life .414 20.4.1 Stress Concentrations .414 20.4.2 Stress Raisers .416 20.4.3 Machining Marks .418 20.4.4 The Effect of Surface Finish 419 20.4.5 Hardness Factors .420 20.5 Summary .421 21 Limits and Fits .423 21.1 Interchangeability 423 21.2 Tolerance 423 21.2.1 Unilateral .424 21.2.2 Bilateral .424 21.3 Limits 424Mould Design Guide xxii 21.4 Fits 425 21.4.1 Running Fit 425 21.4.2 Push Fit .426 21.4.3 Drive Fit 426 21.4.4 Force Fit 426 21.5 British Standard Hole and Shaft Fits .426 21.5.1 Clearance Fit 427 21.5.2 Transition Fit .427 21.5.3 Interference Fit .427 21.6 British Standard Clearance Fits .427 21.7 British Standard Clearance Fits – Hole Basis .429 21.7.1 Example 430 21.8 Geometric Tolerancing 431 22 Impression Blanking 437 22.1 Reasons for Impression Blanking 437 22.2 Example 438 22.2.1 Original Estimate .438 22.2.2 Effect of Running on Six Impressions 439 22.2.3 Effect of Running on a 6-imp Basis with an 18-second Cycle 440 22.2.4 Cycle Required to Achieve Original Profit Level 440 22.2.5 Cycle Required to Break Even .441 22.3 Observations .442 22.4 Summary .442Contents xxii i 22.5 Methods of Blanking Impressions .442 22.5.1 Glueing 443 22.5.2 Gate Blocking 443 22.5.3 Cavity Rotation .443 22.5.4 Blanking the Branch Runner .445 22.6 Summary .445 23 Summary of Mould Calculations 447 23.1 Production Rates .447 23.2 Cooling Channel Diameters 447 23.3 Runner Length Formulae 448 23.4 Gate Design .449 23.5 Ejection Forces .449 23.6 Stress and Strain .450 23.7 Factors of Safety 450 23.7.1 For Brittle Materials .450 23.7.2 For Ductile Materials .450 23.8 Poisson’s Ratio 450 23.9 Moments of Inertia 451 23.9.1 Rectangular Bar .451 23.9.2 Circular Bar .451 23.10 Temperature Stresses .452 23.11 Bending Formulae 452 23.11.1 Section Modulus 453 23.12 Deflection of Beams .453 23.13 Blanking Impressions .454Mould Design Guide xxiv 24 Integrated Design Examples .455 25 Mathematical and Reference Tables .485 25.1 Logarithms 486 25.2 Anti-logarithms .488 25.3 Natural Sines 490 25.4 Natural Cosines .492 25.5 Natural Tangents .494 25.6 Square Roots .496 25.7 Reciprocals 500 25.8 Powers, Roots and Reciprocals .502 25.9 Thermal Properties of Some Common Mould-making Materials .504 25.10 Typical Thermal and Mechanical Properties of Steels for Injection Moulds .505 25.11 Thermal Properties of Plastics Materials .506 25.12 I.S.O. Metric Fine Threads in mm 507 25.13 I.S.O. Metric Coarse Threads in mm 508 25.14 B.S.F. Threads (55°) .509 25.15 Whitworth Threads (55°) .509 25.16 British Pipe Thread (B.S.P.) – Basic Sizes in Inches .510 25.17 British Standard Taper Pipe (B.S.T.P.) Tolerances and Allowances, Turns of Thread .511 25.18 Hardness Comparison Table 512 25.19 Conversion Factors 513Contents xxv 26 Glossary of Moulding Terminology 515 26.1 Time Elements in a Moulding Cycle .515 26.2 Mould and Processing Terminology .517 Index Index A Acrylics applications 39 Acrylonitriles applications 39 Alloys (of polymers) 28–9 Aluminium alloys characteristics 330–1 Amorphous thermoplastics 29–30 Anisoptropic materials 33 Antioxidants 34 Automatic tool design 205–6 anti-rotation keying basic key geometry 239–40 application of shrinkage allowance 218 formulae 219 basic designs 222 collapsible coring 224–6 multisegment cores 227 split tooling 222–3 thread jumping 223–4 cavity rotation 242–4 guidelines 245 key design features 244 commercial systems 270 core unscrewing 234 cavity in fixed half 235–8 cavity in moving half 234–5 fixed core 234 key design features 238–9 driving systems 260 actuation by cylinder 261–3 clutches 266 clutches and rotation control 265–6 electric motors 265 hydraulic motors 263–4 pneumatic motors 263 rack-and-pinion systems 260 stepper motors 267 tool opening movement 260–1 torque limiters 268 gearing geometry 250–2 basic spur gear definitions 252–3 example calculations 253–5 gear selection guidelines 255 gear train design guidelines 255–6 ISO/Imperial conversion 253 general mould design for threads 256 observation 256Mould Design Guide 528 stage 1 – preliminary considerations 256–7 stage 2 – predesign phase 257–8 stage 3 – integrating design features 258 stage 4 – main design phase 259 stage 5 – design review 259 injection moulding considerations 220 ejection speed 220 injection pressure 220 injection speed 220 operating window 221 tool temperature control 221–2 unscrewing speed 220 moving core systems 240–1 key design features 241 rotary unscrewing 227–8 collapsible coring details 228 collapsible coring types 228 multisegment collapsible cores 230–1 two-segment core details 229–30 silicone rubber sleeve cores 231, 233 advantages 231 disadvantages 232 special designs 269–70 thread forms 206 thread geometry 207 British Standard pipe thread 214 form 208–13 jointing threads 214 longscrew threads 214–15 moulded forms 216 number of starts 207 parallel threads 207 taper 213 thread shrinkage compensation 217 effects of incorrect shrinkage 217 form inaccuracy 218 inaccurate diameters 218 pitch inaccuracy 218 two-thread unscrewing designs 245 key design features 245–7, 249 operation 247–9, 250 B Back pressure 16 effects 44–5 Bead blasting 342 Beam deflection 397, 453 Beam theory 390–1 models 392 cantilever beams 392 fixed-end beams 393 simply supported beams 392 Bending force 383 Bending formulae 396, 452 Bending moments 393 neutral axis 393–4 second moment of area 394–5 circular bars 396 rectangular bars 395 Beryllium–copper alloys 84, 93 characteristics 332–4 Bismuth–tin alloys characteristics 334–5Index 529 Blowing agents 34 British Standard hole and shaft fits 426 clearance fit 427–9 transition fit 427 C Carburising 338–9 process 339 Cavitation 17 Cavity cooling 145–7 Cellulose plastics applications 39 Chromium plating 341 Clamping mechanisms 9 combined mechanical– hydraulic systems 13 direct clamping 12 direct hydraulic clamping 12 double toggle joint clamp 10–12 single toggle joint clamp 9–10 toggle mechanisms 9 Commodity plastics 32 Compressive force 383 Cooling channel diameter calculations 447–8 Copolymers 27–8 Core cooling 137 angled hole design 139–40 baffle systems 137–8 fountain systems 138–9 heat pipe 143–4 heat rod 142–3 spiral cooling 141–2 stepped hole design 140–1 Customer definition 3 D Daylight 7 Decompression 14 Deflection 381 Degradation 40, 43–4 Design, good practice 55–6 general arrangement (GA) diagrams 56–7 observing mould tools 58 predesign analysis 56 summary 58 toolmaking concepts 57 Design, step-by-step approach 72 design requirements 71 example 72–3 1 – split line 73–4 2 – gating 75 3 – ejection 75–6 4 – cavity inserts 76–7 5 – venting 78–9 6 – water cooling 79–80 7 – impression centres 80 8 – mould layout 81 9 – sectional view 82 golden rules 71 Design checklist 59 component aesthetics 63 component drawing 60Mould Design Guide 530 component function 61 component geometry 60 component material 61 component tolerances 62 ejection method 63 gating method 62 number of impressions 62 original estimate details 60 predesign 59 quantity required 61 Distance between tie bars 8 Driving systems 260 actuation by cylinder 261–3 clutches 266 clutches and rotation control 265–6 electric motors 265 hydraulic motors 263–4 pneumatic motors 263 rack-and-pinion systems 260 stepper motors 267 tool opening movement 260–1 torque limiters 268 E Ejection force calculations 449 Ejection systems ejection assembly actuation 122 double ejection 129–31 hybrid systems 126–8 hydraulic 125–6 mechanical 122–5 pneumatic 126 ejection force calculation 120 ejection methods 114 ejection forces 119 ejector pins and blades 114–15 sleeve ejectors 116 stripper plate ejection 117 valve ejection 118–19 formulae 120–1 example 121–2 requirements 109 component finish 114 draft angles 109–10 ejection balance 112 gating 111–12 machine ejection features 113 machine specifications 113 material 110–11 mould opening stroke 113 movement control features 114 part geometry 109 tolerances 110 unsatisfactory systems 132 Elastic limit 386 Electrodischarge machining (EDM) mould finishing 342 standard 89–90 wire 91–2 Engineering plastics 32 Epoxides applications 39 Epoxy resin characteristics 335 Ethylene-vinyl acetate applications 39Index 531 F Factor of safety (FOS) 386 brittle materials 387 calculations 450 ductile materials 387 Fatigue background 408–10 calculating shut-off areas 410–12 example 412–14 factors affecting fatigue life 414 effects of surface finish 419–20 hardness factors 420 matching marks 418 stress concentrations 414–16 stress raisers 416–17 observations 407 summary 421 Feed system design 345 cold slug well 346–7 sprue 346 Feed throat 15 Fibrous reinforcement 33 Fillers 34 Fits 425 drive fit 426 force fit 426 push fit 426 running fit 425 Flame retardants 34 Flow promoters 33 Fluorinated polymers applications 39 Fungicides 34 G Gate design 355–60 automatically trimmed gates 360–2 calculations 449 computer simulations 363 diameter 367 effect of time 369 shearing 367–9 establishing correct size 369 computer analysis 370 empirical analysis 370–1 land length 367 manually trimmed gates 360 number and location of gates 363–4 rules 362–3 sizing 365 example 366–7 Gearing geometry 250–2 basic spur gear definitions 252–3 example calculations 253–5 gear selection guidelines 255 gear train design guidelines 255–6 ISO/Imperial conversion 253 General arrangement (GA) diagrams 56–7 Geometric tolerancing 431–5 Granular masterbatch 40 H Hold-on pressure 17 Homopolymers 27Mould Design Guide 532 I Impression blanking calculations 454 example cycle required to achieve original profit level 440–1 cycle required to break even 441 effect of running six impressions 439 effect of running six impressions with 18-second cycle 440 observations 442 original estimate 438–9 summary 442 methods 442 blanking the branch runner 445 cavity rotation 443–4 gate blocking 443 glueing 443 rationale 437–8 summary 445–6 Impressions, number of 62, 65–6, 67–8 appearance 66–7 cavities versus control 68–9 checklist 70 drawing tolerances 67 part geometry 67 quality versus quantity 66 summary 70 Injection moulding 1–3 Injection unit 13–14 hold-on pressure 17 injection speeds and pressures 16–17 reciprocating screw design 14–16 screw forward 16 screw rotation 16 screw speed 18 screw stroke 18–19 Integrated design examples 455 common gate designs 457 mould opening sequence 483 nozzle location on sprue 456 rotating cavity 482 stack tool 459 sub gates 458 two-impression coil platform 464 two-impression family mould 462–3 two-impression forceps mould 470–1 details 472–81 two-impression hot runner mould 461 two-impression spacer mould 466–7 details 468–9 two-impression split tool 460 interchangeability 423 L Limit of proportionality 386 Limits 424–5 M Meld lines 52 Melt flow index (MFI) 36 Moments of inertia circular bars 451 rectangular bars 451 Monomers 25–6Index 533 Mould design 2–3, 379 breakages 380 competition 380 energy costs 380 factor of safety (FOS) 386 brittle materials 387 ductile materials 387 summary 405 Mould finishing 340 bead blasting 342 chromium plating 341 EDM finishing 342 photochemical etching 341–2 polishing 341 vapour blasting 342–3 Mould height 6 Mould maintenance 343 Mould materials 321 heat treatment 335–6 carburising or case hardening 338–9 nitriding 339 pretoughening 338 through-hardening 336–7 tuftriding 340 material characteristics 323 aluminium alloys 330–1 beryllium–copper alloys 332–4 bismuth–tin alloys 334–5 cast steel 326–9 epoxy resin 335 plate steel 324–6 steel 323 zinc alloys 332 material selection 322–3 Mould tool analysis 397 core pins 403 supported cores 404 unsupported cores 403–4 split tool example 400–2 two-plate 397–400 Mould tool definition 3 Moulder definition 3 Moulding process 5 machine design base unit 6 clamp unit 6 clamping mechanisms 9–13 daylight 7 distance between tie bars 8 injection unit 13–16 mould height 6 moulding cycle closing phase 20 cooling and refill phase 21 ejection phase 22 holding time and pressurising phase 20–1 injection phase 20 open phase 21 protection phase 20 screw back phase 21 summary 22 theoretical mould locking force 19–20 Mouldmaking 83 differential shrinkage 96–7 example 97–8Mould Design Guide 534 general construction 85 beryllium–copper 93 cavity construction 85 cavity corrosion and erosion 95 cold hobbing 92 electrodischarge machining (EDM), standard 89–90 electrodischarge machining (EDM), wire 91–2 electroforming 93–4 fabrication 88 gassing and burning 95 grinding 87–8 milling 86 turning 86 general requirements alloy steels 84 beryllium–copper 84 materials 83 mild steel 84 maximum metal conditions 97 Multiplate tool systems stack moulds 285–90 three-plate systems 271–2 operation 273–8 undercut tools 279–80 sequential opening 281–4 N Nucleating agents 33 P Photochemical etching 341–2 Plastics materials additives 33–4 applications 39 cavity filling phase 47 cavity holding pressure phase 48 classification amorphous and semicrystalline thermoplastics 29–30 homopolymers, copolymers and polymer blends 27–9 thermosets and thermoplastics 26–7 commodity plastics 32 cooling and solidification 53 definition 23 engineering plastics 32 flow properties 35 gate freeze-off phase 48 melt compressibility and shrinkage 48 melt flow index (MFI) 36 melting and solidification 30 monomers, polymerisation and polymers 25–6 moulding behaviour of thermoplastics additives 40–1 colouring materials 40 degradation 43–4 drying 41–2 effect of screw rotational speed and back pressure 44 flow characteristics 45 injection speed 45–7Index 535 melt temperature 43 melt temperature, selecting optimal 44 melting 42–3 pretreatment 40 reprocessed materials 40 names and abbreviations 37–9 nature 24–5 polymer molecules 37 reprocessed material 37 shrinkage 31 sinks and voids 49–51 types 23 variable molecular weight 35 weld lines and meld lines 52 Poisson's ratio 388–9, 450 Polishing 341 Polymer blends 28–9 Polymerisation 25–6 Polymers 25–6 Production rate calculations 447 R Reaction pressure 16 Runner design 347 calculating runner length 352–3 example 353–4 cross-section and layout 347–50 length formulae 448–9 rules 350–2 Runnerless moulding 291 full hot runner systems advantages over cold runner moulds 300–4 hydraulically operated needle nozzle 308 multipoint gating 309–10 nozzles and gate bushes 305 open gate nozzles 305–6 spring-operated needle nozzle 307 summary 311 gating 315 pin and edge gating 315 thermal sealing 316 valve gating 316 heating 311 band heating 311 cartridge heaters 312 coil heaters 312 heat pipes 313 integral heating 313 tubular heaters 312 insulated runner systems 298 fully insulated 298–9 semi-insulated 299–300 manifold temperature control 313 closed-loop control 314 open-loop control 314 other factors 314–15 manifold/nozzle interface 318 heating capacity requirements 318 manifold heat-up time 320 nozzle–mould interface 318Mould Design Guide 536 wattage density 319–20 sprueless moulding 291 basic antechamber type 291–3 heated hot sprue brushes 293–6 summary 297 thermal expansion 317 S Screw back 15, 21 Screw rotation 16 effects 44–5 Section modulus 396, 453 Self-annealing 46 Semicrystalline thermoplastics 29–30 Shear force 383–4 Shear heat 16 Shear heating 42 Shrinkage 48 differential 96–7 Silicone rubber sleeve cores 231, 233 advantages 231 disadvantages 232 Sinks 49–51 Specific heat calculations 155 amorphous materials 156 crystalline materials 156–7 enthalpy curves 157–9 example 159–60 Sprue 346 Sprueless moulding 291 basic antechamber type 291–3 heated hot sprue brushes 293 externally heated 295–6 internally heated 294 summary 297 Stack moulds 285–90 Standard mould parts 373 availability 373 base units 374 cooling components 375 ejection components 374 feed systems 374 location and alignment components 374 plates 374 unscrewing components 375 designing with 375 summary 378 toolmaking 376–7 Steel characteristics 323 Steel, cast characteristics 326–9 Steel, plate characteristics 324–6 Stepped control 16 Strain 384 calculations 450 Stress 384 calculations 450Index 537 forces 381–2 bending force 383 compressive force 383 shear force 383–4 tensile force 383 temperature stresses 390 Stress–strain graphs 385 elastic limit 386 limit of proportionality 386 tensile strength 386 yield stress 386 Young's modulus of elasticity 385 Suck back 14 T Temperature control 133–4 beryllium–copper cores and cavities 150 chillers 135 controllers 135 coolants 155 thermal conductance of metals 155 cooling 135–7 cavity cooling 145–7 core cooling 137–44 cooling calculations 155 specific heat 155–60 cooling efficiency 148, 153 cavity material and construction 153–4 channel geometry 154 channel number required 154 coolant flow rate 154 parallel cooling 149 series cooling 148 factors affecting cooling cycle 150 gate and runner 152 mould material 152 moulding material 151 part geometry 151 wall sections 151 heat transfer fluids oil 134 water 134 mould cooling variables 163 moulds 152–3 pulsed mould cooling 161–2 selective 162 summary 163 Temperature stresses 390, 452 Tensile force 383 Tensile strength 386 Thermoplastics 26–7 amorphous and semicrystalline 29–30 flow properties 35 moulding behaviour degradation 43–4 drying 41–2 effect of screw rotational speed and back pressure 44 flow characteristics 45 injection speed 45–7 melt temperature 43 melt temperature, selecting optimal 44 melting 42–3 Thermosets 26–7 ThreadsMould Design Guide 538 application of shrinkage allowance 218 formulae 219 forms 206 geometry 207 British Standard pipe thread 214 form 208–13 jointing threads 214 longscrew threads 214–15 moulded forms 216 parallel threads 207 taper 213 shrinkage compensation 217 effects of incorrect shrinkage 217 form inaccuracy 218 inaccurate diameters 218 pitch inaccuracy 218 Through-hardening 336–7 process 337 Tolerance 423 bilateral 424 geometric tolerancing 431–5 unilateral 424 Toolmaker definition 3 Tuftriding 340 Two-plate mould tools design 99–100 bushes 106 cavity insert 102 cavity plate, front 102 cavity plate, rear 102 cavity support plate 103 chamfers and radii 107 clearances 106 ejection gap 104 ejection system 103 fine tuning mould tune 104–6 guide bushes 107 guide pillar 104 locating or register ring 101 return pins 104 screws 106 split line 102 stand-off buttons 107 support blocks 104 support pillars 106 taper threads 107 top plate 101–2 U Undercut injection mould tools 165–6 angled action form pins key design features 186–7, 188 operation 186, 188 angled lift splits 179–80 formulae 181 key design features 181 operation 180–1 basic designs 168 components 167 curved undercuts 190 key design features 192 operation 190–1 form pins 182 angled action form pins 185Index 539 angled form pins 184–5 key design features 183–4 straight action 182–3 helical gears and pump impellers 196 key design features 172–3 example 173–5 loose inserts 168–70 multiplate systems 279–80 sequential opening 281–4 nonstandard side core designs 188 key design features 190 operation 189–90 undercuts at angle to tool axis 189 normal ejection techniques 196 component material 198 form of undercut 197 satisfactory materials 198 unsatisfactory materials 198–9 offset angle dowels 175–6 establishing point P 177–8 key design features 177 radial undercuts 192–4 key design features 195–6 side cores 178–9 special ejection designs 199 component splitting 200–1 helical ejection 202–3 one-piece moulding 202 splits 170 straight angle dowels 170–1 V Vapour blasting 342–3 Virgin materials 40 Voids 49–51 W Weld lines 52 Y Yield stress 386 Young's modulus of elasticity 385 Z Zinc alloys characteristics 332
كلمة سر فك الضغط : books-world.net The Unzip Password : books-world.net أتمنى أن تستفيدوا من محتوى الموضوع وأن ينال إعجابكم رابط من موقع عالم الكتب لتنزيل كتاب The Mould Design Guide رابط مباشر لتنزيل كتاب The Mould Design Guide
|
|