1 Principles of Mold Design

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Contents

1

1 Principles of Mold Design

Types of Injection Molds
Types of Runners and Gates
1.2.1 Solidifying Systems
1.2.2 Hot Runner Systems
1.2.3 Cold Runner Systems
1.2.3.1 Molds for Processing Elastomers
1.2.3.2 Molds for Processing Thermosets
1.3 Temperature Control in Injection Molds
1.4 Types of Ejectors
1.5 Types of Undercuts
1.6 Special Designs
1.6.1 Molds with Fusible Cores
1.6.2 Prototype Molds of Aluminum
1.6.3 Prototype Molds Made of Plastics
1.7 Status of Standardization for Injection Molds
1.7.1 Standardized Mold Components (as of Mid-2005)
1.7.2 Standardized Electrical Connections for Hot Runner Molds
1.7.3 Terminology Standards for Injection Molds
1.7.3.1 DIN IS0 12165 “Tools for Molding-Components of
Compression and Injection Molds and Die-Casting Dies”
1.7.3.2 DIN 16769 “Components for Gating Systems Terms”
1.7.4 DIN IS0 16916 “Tools for Molding - Tool Specification Sheet
for Injection Molds”

1.8 Standard Mold Components
1.9 Injection Mold for Producing Test Specimens hom Thermoplastic Resins
1.10 Materials Selection
1.10.1 General Requirements for Materials
1.10.2 Tool Steels
1.10.2.1 Case-Hardening Steels
1.10.2.2 Prehardened Steels
1.10.2.3 High-speed Steels
1.10.2.4 Corrosion Resistant Steels
1.10.2.5 Powder-Metallurgical (PM) Steels
1.10.2.6 Cast Ferrous Materials
1.10.3 Non-Ferrous Metals
1.10.3.1 Aluminum Alloys
1.10.3.2 Titanium Alloys
1.10.3.3 Copper Alloys
1.10.4 Anorganic Nonmetallic Materials
1.10.4.1 Ceramic Materials
1.10.5 Surface Treatment Methods
1.10.5.1 Nitriding
1.10.5.2 Carburizing
1.10.5.3 Hard Chrome Plating
1.10.5.4 Hard Nickel Plating
1.10.5.5 Hard Materials Coating
1.11 Materials Properties under Mechanical Stress
1.11.1 Notch Effect under Static Stress
1.11.2 Notch Effect under Dynamic Stress
1.12 Thermal Insulation and Reflector Plates
References in Chapter 1

1.1

1.2

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2 Special Design Features of the Example Molds

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3 Examples

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Single-Cavity Injection Mold for a Polyethylene Cover
Two-Cavity Injection Mold for Elbow Connector
Made from PA 66
Injection Mold for the Body of a Tape-Cassette
Holder Made from High-Impact Polystyrene
Five-Cavity Injection Mold for Tablet Tubes Made from Polystyrene
Four-Cavity Injection Mold for a Polyamide Joint Element
Mold Base with Interchangeable Inserts to Produce Standard Test Specimens

Two-Cavity Rotary Core Mold for a Polyacetal Pipe Elbow
Hot Runner Injection Mold for Car Front Fender
Injection Mold for Magnifying Glass Frame with Handle
16-Cavity Hot-Runner Mold for Cover Caps with Segmented Internal
Contours Made from Polypropylene (PP) or Polyethylene (PE)
Four-Cavity Injection Mold for a Housing Made from
Acrylonitrile-Butadiene-Styrene(ABS)
Four-Cavity Injection Mold for a Nozzle Housing Made from Polyamide
Single Split Cavity Mold for a Threaded Plug Made from Polyacetal (POM)
Demolding a Polyethylene Container with External Undercuts
Injection Mold with Reduced Opening Stroke for Milk Crates from Polyethylene
Two-Cavity Injection Mold for Recessed Refrigerator
Handles Made from Polyamide
Injection Mold for a Grass Catcher Made from Polypropylene
Injection Mold for Hose Connectors Made from Polyamide 6.6
Two-Cavity Injection Mold for the Coil Form of
an Auxiliary Relay
Single-Cavity Hot-Runner Mold for Business Card
Boxes Made from Polypropylene
8-Cavity Injection Mold for Threaded Rings Made from Polyacetal (POM)
Mold for a Pump Housing and Pump Piston Made from Polyacetal
Hot-Runner Injection Mold for Two Film Spools Made from High-Impact Polystyrene
Injection Mold for an Angle Fitting from Polypropylene
Mold for Bushings from Polyamide with Concealed Gating
Injection Mold for the Valve Housing of a Water-Mixing Tap Made from Polyacetal
Mold for a Lid with Three Threads Made from Polyacetal
Two-Cavity Injection Mold for Coupling Sleeves Made from Polyamide
Injection Mold for the Housing of a Polypropylene Vegetable Dicer
Two-Cavity Injection Mold for a Polypropylene Toy Tennis Racket
Two Injection Molds with Two-step Ejection Process for Housing

Components from Polycarbonate
Injection Mold for a Polypropylene Container with
a Threaded Neck
Three-Plate Injection Mold with Stripping Device for a Precision Magazine
6-Cavity Metal-Powder Injection Mold (MIM)
for Transport Fasteners
Mold for a Polyamide V-Belt Pulley
2 x 8-Cavity Hot-Runner Stack Mold for Yoghurt Cups Made from Polypropylene
2 x 2-Cavity Stack Mold for Covers Made from Polypropylene
2 x 5-Cavity Stack Mold for Cases Made from Polypropylene
16-Cavity Hot-Runner Mold for Packaging of
Medical Parts made from Polypropylene
Hot-Runner Stack Mold for a Water Distribution Block Made from Polypropylene
2 x 8-Cavity Stack Mold for Lozenge Box Made from Polystyrene
Two-Cavity Injection Mold for a Tail Light Housing Made from ABS
2 x 2-Cavity Stack Mold with a Hot-Runner System for
Runnerless Molding of Polystyrene Container Lids Using
Direct Edge Gating
2 x 4-Cavity Hot-Runner Stack Mold for Dessert Cups Made from Polypropylene
Hot-Runner Mold for Bumper Fascia Made from Thermoplastic Elastomer
Four-Cavity Hot-Runner Mold for Threaded Covers Made from SAN

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Two-Cavity Hot-Runner Mold for Trim Bezels Made from ABS
Four-Cavity Hot-Runner Mold for Control Flap Made from Polyacetal Copolymer
64-Cavity Hot-Runner Mold for Seals Made from Thermoplastic Elastomer (TPE)
Eight-Cavity Hot-Runner Mold for PP Toothpaste Dispenser
2-Cavity Hot-Runner Mold for Polyethylene Jars
Two-Cavity Hot-Runner Mold for Production of Connectors Made
from Polycarbonate
Four-Cavity Hot-Runner Unscrewing Mold for Cap Nuts Made
from Polyacetal (POM)
Four-Cavity Hot-Runner Mold with a Special Ejector System for a
Retainer Made from Polypropylene
Example 55, 2 x 16-Cavity Two-Component Injection Mold for Microswitch Covers
Made from Polyamide and Thermoplastic Elastomer
32-Cavity Hot-Runner Mold for Production of Packings Made from Polyethylene
12-Cavity Hot-Runner Mold with Edge Gates for Bushings Made from
Polyacetal Copolymer
Single Injection Mold for Sleeves Made from Glass-Fiber and Talcum
Reinforced PA 66
Two-Component Injection Mold for Drink Can Holders Made from

Polypropylene and Ethylene-Propylene Terpolymer
Hot-Runner Mold for Polypropylene Clamping Ring with Internal
Undercut around the Circumference
Injection Mold for Compact Discs Made from Polycarbonate
Single-Cavity Injection Compression Mold for a Cover Plate Made from
Unsaturated Polyester Resin
Two-Cavity Injection Compression Mold for a Housing Component Made
from a Thermosetting Resin
Injection Compression Mold for a Plate Made from Melamine Resin
Five-Cavity Unscrewing Mold for Ball Knobs Made from a Phenolic Resin
Four-Cavity Injection Mold for a Thin-Walled Housing Made from a Phenolic Resin
Thermoset Injection Mold for a Bearing Cover Made from Phenolic Resin
6-Cavity Hot-Runner Mold for Coffee Cup Covers Made from Polypropylene
Two Injection Molds for Overmolding of Polyamide Tubing for
Automobile Power Window Operators
Single-Cavity Injection Mold for a Housing Base Made from Polycarbonate
Connector with Opposing Female Threads Made from
Glass-Fiber-Reinforced Polyamide
Cylindrical Thermoplastic Container with Reduced-Diameter
Opening A Study in Part Release
Single-Cavity Injection Mold for a Lighting Fixture Cover Made
from Polymethylmethacrylate (PMMA)
Injection Mold for a Housing with a Thread Insert Made from Polycarbonate
Mold for Long, Thin, Tubular Parts Made from Polystyrene
Insulated Runner Mold for Three Specimen Dishes Made from Polystyrene
Single-Cavity Injection Mold for a Polypropylene Emergency Button
Eight-Cavity Injection Mold for Battery Caps with Undivided External Thread
and Sealing Cone Made from Polypropylene
Injection Mold for a Curved Pouring Spout Made from Polypropylene
Injection Mold for an ABS Goggle Frame

4-Cavity Hot Runner Mold for Front Ring
Two-Cavity Two-Component Injection Mold for a PC/ABS Bezel with a
PMMA Window
Two-Cavity Injection Mold for Runnerless Production of Polycarbonate
Optical Lenses
Injection Mold with Hydraulic Core Pull for a Cable Socket
Four-Cavity Injection Mold for Pipets Made from PMMA
Two-Cavity Mold for Water Tap Handles Made from PMMA
Two-Cavity Injection Mold for the Automatic Molding of Conveyor
Plates onto a Wire Cable
20-Cavity Hot-Runner Mold for Producing Curtain-Ring Rollers
Made from Polyacetal Copolymer
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3.89 Injection Mold with Attached Hydraulic Core Pull for Automatic
Measuring Tubs Made from PC
3.90 48- and 64-Cavity Hot-Runner Molds for Coating Semi-finished Metal Composite
with Liquid Crystalline LCP Polymer (Outsert Technology)
3.91 24-Cavity Hot-Runner Injection Mold for Polyacetal Spool Cores
3.92 Two-Cavity Hot-Runner Mold for Loudspeaker Covers Made from Polyacetal
3.93 Injection Mold with Air Ejection for Polypropylene Cups
3.94 Molds for Manufacturing Optical Lenses Made from PC
3.95 Two-Cavity Injection Mold for a Polycarbonate Steam Iron Reservoir Insert
3.96 Injection Mold with Pneumatic Spme Bushing for a Headlight

Housing Made from Polypropylene
3.97 Injection Mold for a Mounting Plate (Outsert Technique)
3.98 Twelve-Cavity Hot-Runner Mold for a Polyphthalamide (PPA) Microhousing
3.99 Two-Cavity Injection Mold for Handle Covers Made from
Glass-Fiber-Reinforced Polyacetal
3.100 Four-Cavity Injection Mold for Thin-Walled Sleeves Made from Polyester
3.101 Injection Mold for a Microstructure Made from POM
3.102 Injection Mold for Production of Adjustable Climate Control
Vents via 3-Shot Molding
3.103 Two-Cavity Hot-Runner Injection Mold for an ABS Cover
3.104 Six-Cavity Injection Mold for Retaining Nuts Made from
Polyamide with Metal Inserts
3.105 Single-Cavity Injection Mold for a Switch Housing Made from Polyacetal
3.106 Single-Cavity Injection Mold for a Snap Ring Made from Polyacetal
3.107 Single-Cavity Hot-Runner Injection Mold for High-Density
Polyethylene (PE-HD) Trash Can Lids
3.108 Single-Cavity Hot-Runner Injection Mold for an Air Vent Housing
Made from Acrylonitrile Butadiene Styrene (ABS)
3.109 Single-Cavity Hot-Runner Injection Mold for an ABS Housing
3.110 Single-Cavity Runnerless Injection Mold for a Polystyrene Junction Box
3.1 11 Four-Cavity Hot-Runner Injection Mold for a Polyamide 6,6 Joining Plate
3.1 12 2 x 4-Cavity Hot-Runner Stack Mold for Hinged Covers
3.1 13 16-Cavity Mold with Cold-Runner System for Liquid Silicone Rubber (LSR) Caps
3.114 Two-Cavity Injection Mold for a Styrene-Acrylonitrile Safety Closure
3.1 15 Four-Cavity Unscrewing Mold for Threaded Polypropylene Closures
3.116 Four-Cavity Injection Mold for Polyester Dispenser Heads
3.1 17 Two-Cavity Injection Mold for PMMA Lighting Fixture Cover
3.118 Two-Cavity Injection Mold for Polyacetal Hinges
3.1 19 Eight-Cavity Injection Mold for PE-HD Threaded Caps
3.120 4-Cavity Hot-Runner Mold for Connectors Made from Polystyrene

3.121 Single-Cavity Mold for a Polypropylene Cutlery Basket
3.122 Two-Cavity Injection Mold for Cover Plates Made from Polyacetal
3.123 Single-Cavity Injection Mold for a Joystick Baseplate Made from PA 66
3.124 Single-Cavity Injection Compression Mold for Thermoset V-Belt
Pulley (Injection Transfer Mold)
3.125 16-Cavity Hot-Runner Mold for Paperclips Made from ABS
3.126 Single-Cavity Injection Mold for a PE-HD Clothes Hanger Produced via
Gas-Assisted Injection Molding
3.127 Single-Cavity Injection Mold for a Syringe Shield Produced via Metal
Injection Molding (MIM)
3.128 Three-Station Mold for a Handtool Handle Made &om PP/TPE
3.129 Four-Cavity Injection Mold for Couplings Produced via Metal Injection
Molding (MIM)

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