Syllabus For The Subject Plastics Mould Engineering

 

                      Engineering Plastics

 

 

TABLE OF CONTENTS

 

Chapter 1

 

PART DESIGN PROCESS: CONCEPT TO FINISHED PART

Design Process

Defining Plastic Part Requirements

Mechanical Loading

Temperature

 

Chemical Exposure

Electrical Performance

 

Weather Resistance

 

 

Radiation

 

 

Appearance

 

Agency Approvals

 

 

Life Expectancy

 

Dimensional Tolerances

 

Processing

 

Production Quantities

 

Cost Constraints

 

 

Assembly

 

 

Thermoplastic Processing Methods

 

 

Injection Molding

 

 

Extrusion

 

Thermoforming

 

 

Blow Molding

 

 

Rotomolding

 

Optimizing Product Function

 

Consolidation

 

Hardware

 

 

Finish

 

 

Markings and Logos

 

 

Miscellaneous

 

 

Reducing Manufacturing Costs

 

 

Materials

 

Overhead

 

 

Labor

 

 

Scrap and Rework

 

Prototype Testing

 

 

 

 

Chapter 2

 

GENERAL DESIGN

 

 

Wall Thickness

 

 

Flow Leaders and Restrictors

 

Ribs

 

Rib Design

 

 

Rib Thickness

 

Rib Size

 

 

Rib Location and Numbers

 

 

Bosses

 

 

Gussets

 

 

Sharp Corners

 

Draft

 

 

Holes and Cores

 

 

Undercuts

 

 

Slides and Cores

 

Louvers and Vents

 

 

Molded-In Threads

 

 

Lettering

 

Tolerances

 

 

Bearings and Gears

 

 

 

 

 

 

Chapter 3

 

STRUCTURAL DESIGN

 

 

Structural Considerations In Plastics

 

 

Stiffness

 

 

Viscoelasticity

 

 

Stress-Strain Behavior

 

 

Molding Factors

 

Short-Term Mechanical Properties

 

Tensile Properties

 

Tensile Modulus

 

Tensile Stress at Yield

 

 

Tensile Stress at Break

 

 

Ultimate Strength

 

 

Poisson’s Ratio

 

Compressive Properties

 

Flexural Modulus

 

Coefficient of Friction

 

Long-Term Mechanical Properties

 

Creep Properties

 

 

Stress Relaxation

Fatigue Properties

 

 

Structural Design Formulas

 

 

Use of Moduli

 

 

Stress and Strain Limits

 

Uniaxial Tensile and Compressive Stress

 

Bending and Flexural Stress

 

 

Shear Stress

 

 

Torsion

 

 

Designing for Stiffness

 

 

Part Shape

 

 

Wall Thickness

 

 

Ribs

 

 

Long-Term Loading

 

 

Designing for Impact

 

 

Fatigue Applications

 

 

Thermal Loading

 

 

 

Chapter 4

 

DESIGN FOR ASSEMBLY

 

 

Part Consolidation

 

 

Mechanical Fasteners

 

 

Snap-Fit Joints

 

 

Welding and Bonding

 

Ultrasonic Welding

 

Vibration and Hot-Plate Welding

 

Spin Welding

 

Solvent and Adhesive Bonding

 

 

Retention Features

 

 

Alignment Features

 

 

Orientation

 

Expansion Differences

 

 

Tolerances

 

 

Chapter 5

 

MACHINING AND FINISHING

Drilling and Reaming

 

Tapping

 

Sawing

 

 

Punching, Blanking, and Die Cutting

 

 

Milling

 

 

Turning and Boring

 

Laser Machining

 

Filing

 

 

Sanding

 

 

Polishing and Buffing

 

 

Trimming, Finishing, and Flash Removal

 

 

Chapter 6

 

PAINTING, PLATING, AND DECORATING

Painting

 

 

Types of Paints

 

 

Paint Curing

 

Paint-Selection Considerations

 

 

Spray Painting

 

Other Painting Methods

 

 

Masking

 

Other Design Considerations for Painting

 

 

In-Mold Decorating

 

 

Film-Insert Molding

 

 

Metallic Coatings

 

 

Electroplating

 

 

Design Considerations for Electroplating

 

 

Molding Considerations for Electroplating

 

Vacuum Metallization

 

 

Design Considerations for Vacuum Metallization

 

 

EMI/RFI Shielding

 

 

Design Considerations for EMI/RFI Shielding

 

 

Printing

 

 

Labels and Decals

 

Texture

 

 

Chapter 7

 

MOLD DESIGN

Mold Basics

 

 

Types of Molds

 

Mold Bases and Cavities

 

 

Molding Undercuts

 

Part Ejection

 

Mold Venting

 

 

Parting-Line Vents

 

 

Vent Placement

 

 

Sprues, Runners, and Gates

 

 

Sprues

 

 

Runners

 

 

Runners for Multi-cavity Molds

 

 

Gates

 

 

Other Gate Designs

 

 

Gate Optimization

 

 

Gate Position

 

Hot-Runner Systems

 

 

Hot-Runner Designs

 

 

Hot-Runner Gates

 

 

Valve Gates

 

 

Thermal Expansion and Isolation

 

 

Flow Channel Size

 

Mold Cooling

 

Mold-Cooling Considerations

 

 

Cooling-Channel Placement

 

Cooling-Line Configuration

 

Coolant Flow Rate

 

Mold Shrinkage

 

Mold Metals

 

 

Surface Treatments

 

 

Mold Cost and Quality

 

Plastics Mould Engineering

APPENDICES

Index

Part Design Checklist