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عدد المساهمات : 19025 التقييم : 35575 تاريخ التسجيل : 01/07/2009 الدولة : مصر العمل : مدير منتدى هندسة الإنتاج والتصميم الميكانيكى
| موضوع: كتاب Robust Process Development and Scientific Molding الإثنين 23 سبتمبر 2019, 9:42 am | |
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أخوانى فى الله أحضرت لكم كتاب Robust Process Development and Scientific Molding Theory and Practice Suhas Kulkarni
و المحتوى كما يلي :
Contents IX Contents 1 Introduction to Scientific Processing . 1 1.1 The Evolution and Progress of Injection Molding . 1 1.2 The Molding Process . 1 1.3 The Three Types of Consistencies Required in Injection Molding 2 1.4 Scientific Processing 4 1.5 The Five Critical Factors of Molding . 5 1.5.1 Part Design . 5 1.5.2 Material Selection . 6 1.5.3 Mold Design and Construction . 6 1.5.4 Machine Selection . 6 1.5.5 Molding Process . 6 1.6 Concurrent Engineering 7 2 Introduction to Polymers and Plastics 9 2.1 Polymers 9 2.2 Molecular Weight and Molecular Weight Distribution 10 2.3 Polymer Morphology (Crystalline and Amorphous Polymers) . 12 2.4 Role of Morphology in Injection Molding 16 2.4.1 Differences in Shrinkage Between Amorphous and Crystalline Materials 16 2.4.2 Melt Processing Range . 16 2.4.3 Mold Filling Speed . 17 2.4.4 Mold Temperatures . 17 2.4.5 Barrel Heat Profile . 18 2.4.6 Screw Recovery Speeds . 19 2.4.7 Nozzle Temperature Control 19 2.4.8 Cooling Times 19 2.4.9 Mechanical Properties . 19 2.4.10 Optical Clarity 20 2.5 Thermal Transitions in Polymers 20 2.6 Shrinkage in Polymers 23X Contents 3 Polymer Rheology . 27 3.1 Viscosity 27 3.2 Newtonian and Non-Newtonian Materials . 29 3.3 Viscosity in Polymer Melts . 30 3.4 Effect of Temperature on Viscosity 32 3.5 Velocity and Shear Rate Profiles . 33 3.6 Application to Injection Molding . 35 3.6.1 Flow Imbalance in an 8-Cavity Mold 35 3.6.2 Racetrack Effect in a Part with Constant Thickness . 37 3.6.3 Stress Build-Up in Molded Parts 37 3.6.4 Warpage Difference Between Cavities . 38 3.7 Solving Flow Imbalances Using Melt Rotation Techniques 38 3.8 Characterization of Polymer Viscosity . 40 4 Plastic Drying . 43 4.1 Problems in Melt Processing Related to the Presence of Moisture 44 4.1.1 Degradation of Plastic 45 4.1.2 Presence of Surface Defects . 45 4.2 Hygroscopic Polymers . 48 4.3 Drying of Plastics 50 4.3.1 Drying Temperatures and Times . 50 4.3.2 Relative Humidity and Dewpoint . 52 4.3.3 Air Flow Rate . 52 4.4 Equipment for Drying Plastics 53 4.4.1 Oven Dryers 53 4.4.2 Hot Air Dryers 53 4.4.3 Desiccant Dryers 53 4.4.4 Classifications Based on the Location of the Dryer . 54 4.5 Determination of the Amount of Moisture . 54 4.5.1 The Glass Slide Technique (TVI Test) . 54 4.5.2 The Karl-Fischer Titration Method . 55 4.5.3 Electronic Moisture Analyzer 55 4.5.4 Measurement of the Dew Point . 56 4.6 ‘Overdrying’ or Overexposure to Drying Temperatures 56 4.7 Cautions 62 4.8 Prevention of Overexposure to Longer Drying Times . 63 4.9 Overdrying Controller . 63Contents XI 5 Common Plastic Materials and Additives . 67 5.1 Classification of Polymers 67 5.2 Commercially Important Plastics 68 5.2.1 Polyolefins 68 5.2.2 Polymers from Acrylonitrile, Butadiene, Styrene, and Acrylate . 69 5.2.3 Polyamides (PA) . 70 5.2.4 Polystyrenes (PS) 71 5.2.5 Acrylics . 72 5.2.6 Polycarbonates (PC) . 72 5.2.7 Polyesters . 72 5.2.8 Polyvinyl Chloride (PVC) 72 5.2.9 Polyoxymethylene (POM or Acetal) . 73 5.2.10 Fluoropolymers . 73 5.3 Additives 74 5.3.1 Fillers . 74 5.3.2 Plasticizers 74 5.3.3 Flame Retardants 74 5.3.4 Anti-Aging Additives, UV Stabilizers 75 5.3.5 Nucleating Agents . 75 5.3.6 Lubricants 75 5.3.7 Processing Aids . 76 5.3.8 Colorants . 76 5.3.9 Blowing Agents 76 5.3.10 Other Polymers 76 5.4 Closing Remarks . 77 6 Injection Molding . 79 6.1 The History of Injection Molding 79 6.2 Injection Molding Machines and Their Classifications 79 6.3 Machine Specifications . 82 6.3.1 Clamp Force (Tonnage) 82 6.3.2 Shot Size . 82 6.3.3 Screw Diameter and L/D Ratio . 83 6.3.4 Plasticating Capacity 83 6.3.5 Maximum Plastic Pressure . 83 6.4 The Injection Molding Screw 83 6.5 Screw Designs . 86XII Contents 6.6 The Check Ring Assembly . 87 6.7 Intensification Ratio (IR) 87 6.8 Selecting the Right Machine for the Mold . 88 6.8.1 Physical Size of the Mold . 88 6.8.2 Tonnage of the Machine . 90 6.8.3 Percentage Shot Size Used . 91 6.8.4 Residence Time of the Material in the Barrel 92 7 Scientific Processing and Scientific Molding . 95 7.1 Introduction . 95 7.1.1 Process Robustness . 96 7.1.2 Process Consistency 96 7.2 Storage and Drying of Resin . 99 7.2.1 Plastic Drying . 99 7.3 Setting of the Melt Temperatures . 102 7.4 Setting Mold Temperatures 103 7.5 The Injection Molding Cycle . 104 7.5.1 Speed and Pressure . 104 7.5.2 Pressure Limited Process 105 7.5.3 Injection, Pack, and Hold 105 7.5.4 Decoupled MoldingSM . 106 7.5.5 Intensification Ratio (IR) 108 7.5.6 Screw Speed 108 7.5.7 Back Pressure 109 7.6 Process Optimization – The 6-Step Study . 110 7.6.1 Step 1: Optimization of the Injection Phase –Rheology Study . 110 7.6.2 Step 2: Determining the Cavity Balance – Cavity Balance Study . 118 7.6.3 Step 3: Determining the Pressure Drop – Pressure Drop Studies 124 7.6.4 Step 4: Determining the Process Window – Process Window Study 128 7.6.5 Step 5: Determining the Gate Seal Time – Gate Seal Study 132 7.6.6 Step 6: Determining the Cooling Time – Cooling Time Study 135 7.6.7 Optimization of Screw Speed and Back Pressure . 137 7.6.8 Post-Mold Shrinkage Studies 138 7.7 Recommended Mold Function Qualification Procedure 141 7.8 Recommended Adjustments to Maintain Process Consistency and Robustness . 142 7.9 Process Documentation . 143Contents XIII 8 Design of Experiments for Injection Molding 145 8.1 Parameters in Injection Molding . 145 8.2 Terminology . 149 8.2.1 Factor . 149 8.2.2 Response . 149 8.2.3 Level 150 8.2.4 Designed Experiment . 150 8.3 Relationships Between the Number of Factors, Levels, and Experiments . 151 8.4 Balanced Arrays 152 8.5 Interactions 154 8.6 Confounding or Aliasing 156 8.7 Randomization . 158 8.8 Factorial Experiments 159 8.9 Data Analysis . 159 8.9.1 Tornado Charts . 161 8.9.2 Contour Plots 162 8.9.3 Prediction Equation 162 8.9.4 Process Sensitivity Charts . 164 8.10 Using the Results from DOE . 165 8.10.1 Process Selection . 165 8.10.2 Cavity Steel Adjustment . 165 8.10.3 Process Adjustment Tool 166 8.10.4 Setting Process Change Tolerances . 166 8.10.5 Setting Alarm Limits 166 8.10.6 Reducing Inspection 167 9 The Aesthetic, the Dimensional, and the Control Process Window 169 9.1 The Aesthetic Process Window (APW) . 169 9.2 The Dimensional Process Window (DPW) 171 9.3 The Control Process Window (CPW) . 171 9.4 Multiple Dimensions . 173 9.5 Multiple Cavities . 175 9.6 Closing Remarks . 175 10 Mold Qualification Flowchart, Production Release, and Troubleshooting . 177 10.1 Mold Qualification Flowchart 177 10.1.1 Mold Function Qualification Procedure 177 10.1.2 Mold and Part Quality Qualification Procedure . 177XIV Contents 10.2 Mold Qualification Checklist . 179 10.3 Process Documentation . 180 10.3.1 Process Sheet . 180 10.3.2 Waterline Diagrams . 181 10.3.3 Mold Temperature Maps 182 10.3.4 Setup Instructions 182 10.3.5 Operator Instructions . 183 10.4 Documentation Books 183 10.5 Qualification Production Runs 183 10.6 Mold Specific Troubleshooting Guide 185 10.7 Molding Startup and Shutdown 185 10.7.1 Purging 185 10.7.2 Startup of a Molding Machine . 186 10.7.3 Shutdown of a Molding Machine 187 10.8 Troubleshooting 187 10.9 Important Equipment and Tools for Qualifications and Troubleshooting . 190 10.10 Common Defects, Their Cause, and Prevention 193 11 Miscellaneous Topics Affecting the Process − Mold Cooling, Venting, and Regrind Management 195 11.1 Mold Cooling . 195 11.1.1 Number of Cooling Channels . 195 11.1.2 Reynolds Number of the Coolant Flow . 196 11.1.3 Type of Coolant 197 11.1.4 Series and Parallel Cooling 197 11.2 Venting 198 11.2.1 Dimensions of the Vent . 200 11.2.2 Primary Vent Depths . 201 11.2.3 Location of Vents 203 11.2.4 Forced Venting or Vacuum Venting 204 11.3 Regrind 205 11.3.1 Effect of the Molding Process on the Part Properties 205 11.3.2 Using Regrind . 207 11.3.3 Batch and Continuous Processes of Incorporating Regrind . 207 11.3.4 Estimating the Amount of Regrind from different Generations . 208 11.3.5 Effect of Regrind on Processing 210 11.3.6 Closing Remarks . 211Contents XV 12 Related Technologies and Topics 213 12.1 Cavity Pressure Sensing Technology 213 12.1.1 Sensors and Output graphs 213 12.1.2 Types and Classification of Pressure Sensors 215 12.1.3 Use of Information from the Pressure Graphs . 217 12.1.4 Controlling the Process with Cavity Pressure Sensors 219 12.1.5 Sensor Locations . 221 12.2 Building a Knowledge Base 221 12.3 Concurrent Engineering in Injection Molding . 223 12.3.1 The Product Designer . 225 12.3.2 The Tooling Engineer . 226 12.3.3 The Mold Designer and Mold Maker . 226 12.3.4 The Material Supplier . 226 12.3.5 The Process Engineer . 227 12.3.6 The Quality Engineer . 227 12.3.7 The Sales Team at the Molder 228 12.3.8 Mandatory for All Departments 228 12.3.9 Implementing Concurrent Engineering . 229 Appendix A Materials Data Sheet . 231 Appendix B Conversion Tables for Commonly Used Process Parameters . 239 Appendix C Water Flow Tables . 240 Appendix D Part Design Checklist 243 Appendix E Mold Design Checklist . 245 Appendix F Mold Qualification Checklist: 247 Appendix G Regrind Tables – Percentage of regrind in total shot 249 Subject Index . 251
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