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Materials for Injection Molds | |
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Steels | |
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Summary | |
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Case-Hardening Steels | |
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Nitriding Steels | |
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Through-Hardening Steels | |
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Heat-Treated Steels | |
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Martensitic Steels | |
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Hard Mold Alloys | |
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Corrosion-Resistant Steels | |
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Refined Steels | |
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Cast Steel | |
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Nonferrous Metallics | |
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Copper Alloys | |
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Zinc and its Alloys | |
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Aluminum Alloys | |
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Bismucth-Tin Alloys | |
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Materials for Electrolytic Deposition | |
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Surface Treatment of Steels for Injection Molds | |
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General Information | |
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Heat Treatment of Steels | |
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Thermochemical Treatment Methods | |
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Electrochemical Treatments | |
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Coating at Reduced Pressure | |
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Laser Surface Treatment | |
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Laser Hardening and Re-Melting | |
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Laser Alloying, Dispersing, and Coating | |
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Electron Beam Hardening | |
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Lamcoat Coating | |
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References | |
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Mold Making Techniques | |
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Production of Metallic Injection Molds and Mold Inserts by Casting | |
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Casting Methods and Cast Alloys | |
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Sand Casting | |
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Precision Casting Techniques | |
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Rapid Tooling for Injection Molds | |
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State of the Art | |
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Direct Rapid Tooling | |
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Indirect Rapid Tooling (Multistage Process Chains) | |
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Outlook | |
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Hobbing | |
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Machining and Other Material Removing Operations | |
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Machining Production Methods | |
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Surface Treatment (Finishing) | |
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Electric-Discharge Forming Processes | |
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Electric-Discharge Machining (EDM) | |
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Cutting by Spark Erosion with Traveling-Wire Electrodes | |
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Electrochemical Machining (ECM) | |
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Electrochemical Material Removal-Etching | |
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Surfaces Processed by Spark Erosion or Chemical Dissolution (Etching) | |
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Laser Carving | |
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Rapid Tooling with LASERCAV | |
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Molds for the Fusible-Core Technique | |
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Molds for Sheathing the Fusible Cores | |
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Molds for Making the Fusible Cores | |
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References | |
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Procedure for Estimating Mold Costs | |
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General Outline | |
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Procedures for Estimating Mold Costs | |
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Cost Group I: Cavity | |
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Computation of Working Hours for Cavities | |
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Time Factor for Machining Procedure | |
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Machine Time for Cavity Depth | |
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Time Consumption for Cavity Surface | |
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Time Factor for Parting Line | |
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Time Factor for Surface Quality | |
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Machining Time for Fixed Cores | |
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Time Factor for Tolerances | |
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Time Factor for Degree of Difficulty and Multifariousness | |
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Time Factor for Number of Cavities | |
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Computation of Working Hours for EDM Electrodes | |
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Cost Group II: Basic Molds | |
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Cost Group III: Basic Functional Components | |
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Sprue and Runner System | |
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Runner System | |
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Hot-Runner Systems | |
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Heat-Exchange System | |
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Ejector System | |
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Cost Group IV: Special Functions | |
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Other Cost Calculation Methods | |
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Costs Based on Similarity Considerations | |
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The Principle behind Hierarchical Similarity Searching | |
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References | |
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The Injection Molding Process | |
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Cycle Sequence in Injection Molding | |
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Injection Molding of Thermoplastics | |
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Injection Molding of Crosslinkable Plastics | |
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Terms Used in Connection with Injection Molds | |
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Classification of Molds | |
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Functions of the Injection Mold | |
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Criteria for Classification of Molds | |
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Basic Procedure for Mold Design | |
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Determination of Mold Size | |
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The Flow Length/Wall Thickness Ratio | |
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Computation of Number of Cavities | |
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Cavity Layouts | |
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General Requirements | |
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Presentation of Possible Solutions | |
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Equilibrium of Forces in a Mold During Injection | |
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Number of Parting Lines | |
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References | |
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Design of Runner Systems | |
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Characterization of the Complete Runner System | |
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Concept and Definition of Various Types of Runners | |
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Standard Runner Systems | |
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Hot-Runner Systems | |
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Cold-Runner Systems | |
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Demands on the Runner System | |
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Classification of Runner Systems | |
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The Sprue | |
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Design of Runners | |
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Design of Gates | |
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Position of the Gate at the Part | |
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Runners and Gates for Reactive Materials | |
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Elastomers | |
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Thermosets | |
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Effect of Gate Position for Elastomers | |
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Runners for Highly-Filled Melts | |
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Qualitative (Flow Pattern) and Quantitative Computation of the Filling Process of a Mold (Simulation Models) | |
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Introduction | |
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The Flow Pattern and its Significance | |
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Using the Flow Pattern for Preparing a Simulation of the Filling Process | |
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Theoretical Basis for Producing a Flow Pattern | |
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Practical Procedure for Graphically Producing a Flow Pattern | |
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Quantitative Analysis of Filling | |
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Analytical Design of Runners and Gates | |
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Special Phenomena Associated with Multiple Gating | |
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Design of Gates and Runners for Crosslinking Compounds | |
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Elastomers | |
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Thermosets | |
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References | |
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Design of Gates | |
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The Sprue Gate | |
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The Edge or Fan Gate | |
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The Disk Gate | |
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The Ring Gate | |
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The Tunnel Gate (Submarine Gate) | |
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The Pinpoint Gate in Three-Platen Molds | |
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Reversed Sprue with Pinpoint Gate | |
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Runnerless Molding | |
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Molds with Insulated Runners | |
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Temperature-Controlled Runner Systems--Hot Runners | |
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Hot-Runner Systems | |
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Cold Runners | |
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Special Mold Concepts | |
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Stack Molds | |
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Molds for Multicomponent Injection Molding | |
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References | |
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Venting of Molds | |
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Passive Venting | |
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Active Venting | |
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Venting of Gas Counter-Pressure Injection Molds | |
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References | |
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The Heat Exchange System | |
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Cooling Time | |
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Thermal Diffusivity of Several Important Materials | |
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Thermal Diffusivity of Elastomers | |
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Thermal Diffusivity of Thermosets | |
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Computation of Cooling Time of Thermoplastics | |
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Estimation | |
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Computation of Cooling Time with Nomograms | |
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Cooling Time with Asymmetrical Wall Temperatures | |
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Cooling Time for Other Geometries | |
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Heat Flux and Heat-Exchange Capacity | |
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Heat Flux | |
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Analytical, Thermal Calculation of the Heat-Exchange System Based on the Specific Heat Flux (Overall Design) | |
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Analytical Thermal Calculation | |
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Numerical Computation for Thermal Design of Molded Parts | |
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Two-Dimensional Computation | |
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Three-Dimensional Computation | |
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Simple Estimation of the Heat Flow at Critical Points | |
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Empirical Correction for Cooling a Corner | |
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Practical Design of Cooling Systems | |
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Heat-Exchange Systems for Cores and Parts with Circular Cross-Section | |
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Cooling Systems for Flat Parts | |
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Sealing of Cooling Systems | |
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Dynamic Mold Cooling | |
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Empirical Compensation of Corner Distortion in Thermoplastic Parts from Heat-Flux Differences | |
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Calculation for Heated Molds for Reactive Materials | |
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Heat Exchange in Molds for Reactive Materials | |
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Heat Balance | |
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Temperature Distribution | |
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Practical Design of the Electric Heating for Thermoset Molds | |
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References | |
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Shrinkage | |
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Introduction | |
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Definition of Shrinkage | |
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Tolerances | |
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Causes of Shrinkage | |
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Causes of Anisotropic Shrinkage | |
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Causes of Distortion | |
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Effect of Processing on Shrinkage | |
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Supplementary Means for Predicting Shrinkage | |
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References | |
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Mechanical Design of Injection Molds | |
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Mold Deformation | |
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Analysis and Evaluation of Loads and Deformations | |
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Evaluation of the Acting Forces | |
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Basis for Describing the Deformation | |
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Simple Calculation for Estimating Gap Formation | |
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More Accurate Calculation for Estimating Gap Formation and Preventing Flash | |
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The Superimposition Procedure | |
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Coupled Springs as Equivalent Elements | |
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Computation of the Wall Thickness of Cavities and Their Deformation | |
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Presentation of Individual Cases of Loading and the Resulting Deformations | |
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Computing the Dimensions of Cylindrical Cavities | |
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Computing the Dimensions of Non-Circular Cavity Contours | |
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Computing the Dimensions of Mold Plates | |
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Procedure for Computing Dimensions of Cavity Walls under Internal Pressure | |
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Deformation of Splits and Slides under Cavity Pressure | |
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Split Molds | |
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Preparing for the Deformation Calculations | |
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Geometrical Simplifications | |
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Tips on Choosing Boundary Conditions | |
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Sample Calculations | |
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Other Loads | |
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Estimating Additional Loading | |
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References | |
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Shifting of Cores | |
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Estimating the Maximum Shifting of a Core | |
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Shifting of Circular Cores with Lateral Pinpoint Gate at the Base (Rigid Mount) | |
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Shifting of Circular Cores with Disk Gates (Rigid Mount) | |
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Basic Examination of the Problem | |
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Results of the Calculations | |
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Shifting of Cores with Various Types of Gating (Rigid Mount) | |
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Shifting of Inserts | |
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Analytical Calculation of Deformation of Metal Inserts Using a Cylindrical Roll Shell as an Example | |
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Design Examples for Core Mounting and Alignment of Deep Cavities | |
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References | |
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Ejection | |
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Summary of Ejection Systems | |
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Design of the Ejection System--Ejection and Opening Forces | |
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General Discussion | |
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Methods for Computing the Release Forces | |
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The Release Forces for Complex Parts Exemplified with a Fan | |
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Numerical Computation of Demolding Processes (for Elastomer Parts) | |
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Estimating the Opening Forces | |
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Types of Ejectors | |
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Design and Dimensions of Ejector Pins | |
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Points of Action of Ejector Pins and Other Elements of Demolding | |
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Ejector Assembly | |
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Actuation of the Ejector Assembly | |
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Means of Actuation and Selection of Places of Action | |
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Means of Actuation | |
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Special Release Systems | |
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Double-Stage Ejection | |
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Combined Ejection | |
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Three-Plate Molds | |
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Ejector Return | |
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Ejection of Parts with Undercuts | |
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Demolding of Parts with Undercuts by Pushing Them off | |
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Permissible Depth of Undercuts for Snap Fits | |
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Demolding of Threads | |
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Demolding of Parts with Internal Threads | |
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Molds with Unscrewing Equipment | |
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Demolding of Parts with External Threads | |
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Undercuts in Noncylindrical Parts | |
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Internal Undercuts | |
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External Undercuts | |
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Molds with Core-Pulling Devices | |
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References | |
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Alignment and Changing of Molds | |
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Function of Alignment | |
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Alignment with the Axis of the Plasticating Unit | |
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Internal Alignment and Interlocking | |
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Alignment of Large Molds | |
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Changing Molds | |
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Systems for a Quick Change of Molds for Thermoplastics | |
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Mold Exchanger for Elastomer Molds | |
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References | |
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Computer-Aided Mold Design and the Use of CAD in Mold Construction | |
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Introduction | |
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The Flow Pattern Method Pointed the Way Forward | |
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Geometry Processing Marks the Key to Success | |
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Complex Algorithms Mastered | |
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Simulation Techniques Still Used Too Infrequently | |
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Simpler and Less Expensive | |
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The Next Steps already Carved out | |
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CAD Use in Mold Design | |
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Introduction | |
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Principles of CAD | |
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CAD Application in Mold-Making | |
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Selection and Introduction of CAD Systems | |
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References | |
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Maintenance of Injection Molds | |
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Advantages of Maintenance Schedules | |
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Scheduling Mold Maintenance | |
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Data Acquisition | |
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Data Evaluation and Weak-Point Analysis | |
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Computer-Based Support | |
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Storage and Care of Injection Molds | |
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Repairs and Alterations of Injection Molds | |
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References | |
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Measuring in Injection Molds | |
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Sensors in Molds | |
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Temperature Measurement | |
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Measuring Melt Temperatures in Molds Using IR Sensors | |
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Pressure Measurement | |
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Purpose of Pressure Measurement | |
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Sensors for Measuring Melt Pressures in Molds | |
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Use of Sensor-Transducer Probes | |
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Process Optimization | |
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Monitoring Quality | |
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References | |
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Mold Standards | |
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References | |
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Temperature Controllers for Injection and Compression Molds | |
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Function, Method, Classification | |
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Control | |
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Control Methods | |
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Preconditions for Good Control Results | |
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Selection of Equipment | |
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Connection of Mold and Equipment--Safety Measures | |
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Heat Carrier | |
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Maintenance and Cleaning | |
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References | |
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Steps for the Correction of Molding Defects During Injection Molding | |
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References | |
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Special Processes--Special Molds | |
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Injection Molding of Microstructures | |
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Molding Technology and Process Control | |
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Production Processes for Microcavities | |
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In-Mold Decoration | |
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Processing of Liquid Silicone | |
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Evacuation | |
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Gate | |
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Demolding | |
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Temperature Control | |
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Cold-Runner Technique | |
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Injection-Compression Molding | |
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References | |
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Index | |