Plastics Engineered Product Design Part 1 pdf

Plastics engineered product design 1.Plastics 2.Engineering design %.New products I.Title ILRosato, Donald V.. Melt Index Viscoelasticities Glass Transition Temperatures Melt Temperatu

Plastics

Engineered Product

Design

Dominick Rosato and Donald Rosato

ELSEVIER

Japan

Copyright 0 2003 Elsevier Ltd

All rights reserved No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the publishers

British Library Cataloguing in Publication Data

Rosato, Dominick V

Plastics engineered product design

1.Plastics 2.Engineering design %.New products

I.Title ILRosato, Donald V (Donald Vincent), 1947-

620.1’923

ISBN 1856174166

No responsibility is assumed by the Publisher for any injury and/or damage to persons or

property as a matter of products liability, negligence or otherwise, or from any use or

operation of any methods, products, instructions or ideas contained in the material herein

Published by

Elsevier Advanced Technology,

The Boulevard, Langford Lane, Kidlington, Oxford OX5 lGB, UK

Tel: +44(0) 1865 843000

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Typeset by Land & Unwin, Bugbrooke

Printed and bound in Great Britain by Biddles Ltd, Guildford and King’s Lynn

Thermosets Crosslinked Thermoplastics Reinforced Plastics

Thermal Expansions Ductilities

Toughness Tolerances/Shrinkages Compounds

Prepregs Sheet Molding Compounds Bulk Molding Compounds Commodity & Engineering Plastics Elastomers/Rubbers

Morphology/Molecular Structure/Mechanical Plastic behaviors

Property Densities Molecular Weights Molecular Weight Distributions Viscosities and Melt Flows

Melt Index Viscoelasticities Glass Transition Temperatures Melt Temperatures

Castings Coatings Compression Moldings Reaction Injection Moldings Rotational Moldings

Variables

FALL0 approach

Chapter 2 DESIGN OPTIMIZATION

Introduction Terminology Engineering Optimization Design Foundation Problem/Solution Concept Design Approach

Model Less Costly Model Type Design Analysis Approach Computer S o h a r e Viscoelasticity

Dynamic/Static Mechanical Behavior

Energy and Motion Control

Basic Design Theory

Fiber Strength Theory

Fiber Geometry on Strength

Stiffness-Viscoelasticity

Creep and Stress Relaxation

Conceptual design approach

Overview Stress-Strain Analysis Plain Reinforced Plates Composite Plates Rending of Beams and Plates Structural Sandwiches Stiffness

Stresses in Sandwich Beams Axially-Loaded Sandwich Filament-Wound Shells, Internal Hydrostatic Pressure

Basic Equations Weight of Fiber Minimum Weight Isotensoid Design Geodesic-Isotensoid Design

Load determination Design analysis process Reinforced Plastic Analysis Stress Analysis

Stress-strain behavior Rigidity (EI)

Hysteresis Effect Poisson’s Ratio Brittleness Ductile Crazing Stress Whitening Surface Stresses and Deformations Combined stresses

Creep Fatigue Reinforcement performance

Chapter 4 PRODUCT DESIGN

Introduction Reinforced Plastic Monocoque Structure Geometric shape

Modulus of Elasticity E1 theory

Underground Storage Tank

Hopper Rail Car Tank

Highway Tank

Very Large Tank

Corrosive Resistant Tank

Permeability Cushioning

House of the Future House Top

Transportation Automobile Truck Aircraft Marine Application Building

Boat Underwater Hull Missile and Rocket Electrical/Electronic Shielding Electrical Device Radome

Surgical Product Dental Product Health Care Medical

Recreation Appliance Furniture Water filter Lumber Metal Metal Replacement with Plastic Performance Behavior

Moisture Effect Long Term vs Short Term Loading

Stress Concentration Coefficient of Expansion Bolt Torque Effcct Impact Barrier Vehicle Oil Pan Attachment Design limitation and constraint

Chapter 5 COMPUTER-AIDED DESIGN

Technology overview Computers and people Geometric modeling Design accuracy and efficiency

Application Designing Graphics Structural Analysis Sofnvare Analysis Finite element analysis

Synthesizing design

CAD special use

Optimization CAD Prototyping Rapid Prototyping CAD standard and translator

Data sharing

Engineered personal computer

CAD editing

CIM changing

Computer- based training

IBM advances computer

Artificial intelligence

Plastic Toys-Smart computer

Computer devices via DNA

Design via internet

PLASTIC PERFORMANCE

Overview

Influencing Factor Selecting plastic

Comparison Worksheet Thermal Property Thermal Expansion/Contraction Hyperenvironment

Chapter 7

Smoke Electrical/Electronic Corrosion resistance Chemical resistance Friction

Tolerance Limit Processing Effect Recycled plastic Engineering data information source Publication

Industry Societies Encyclopedia and Industrial Books Standards

Engineering Information Information Broker Engineering Societies and Associations Designs

Databases Websites Training programs

Thomas Register

DESIGN RELIABILITY

Testing Classiflmg Test

Laboratory Quality control Quality and Reliability Total Quality Management Quality and Design

Statistics Testing; QC, statistics, and people Product failure

Spectrum Loading and Cumulative Damage Crack Growth and Fracture Mechanics Fatigue and Stress Concentration Fatigue Loading and Laboratory Testing Predicting Long Time Reliability

Meaning of data Safety factor Safety Factor Example

Contents xi

Chapter 8 SUMMARY

Overview

Market Size Customer Constraint Responsibility Responsibility Commensurate with Ability Risk

Acceptable Risk

Predicting Performance Design Verification Perfection

Ethics Ergonomic

xiv Preface acknowledgement

material selection for end use applications where factors such as thermal, chemical, electrical, optical, and environmental properties are important The mechanical engineer will also gain an understanding of the manufacturing constraints imposed by mold and die designs as well

as the processes used to manufacture plastic products The plastic engineer will gain a better understanding of the principles of stress analysis, failure modes in structures, and the use of computer based finite element methods for in depth stress and deformation calculations This book will provide the means that both can expand their expertise from the synergistic effect of combining both disciplines

This book will provide many fundamentals with their required details so that the reader can become familiar and put to use the different design approaches Reviews relate to fabricating over 35,000 plastics available worldwide to produce the many millions of different products that are used worldwide

Information is concise and comprehensive Engineering and non- engineering principles reviewed have been in use worldwide and are published in many different forms that are included in the bibliography The book also lists commercial software sources as well as material databases The reader, with or without design or engineering experience, can understand these principles It will be invaluable to the most experienced designers or engineers, as well as providing a firm basis for the novice I t meets the designer’s goal that is essentially an exercise in predicting product performances

Its unique approach will expand and enhance your knowledge of plastic technology Plastic ranges of behavior are presented to enhance one’s capability in fabricating products to meet different performances, low cost requirements, and profits Important basic concepts are presented such as understanding the advantages of different materials and product shapes This full presentation provides the background needed to

understand performance analysis and the design methods useful to the designer It provides an important tool for approaching the target “get-

to-market-right-the-first-time.”

Patents or trademarks may cover information presented No authorization to utilize these patents or trademarks is given or implied; they are discussed for information purposes only The use of general descriptive names, proprietary names, trade names, commercial designations, or the like does not in any way imply that they may be used freely

A practical approach was used to obtain the information contained in

this book While information presented represents useful information

that can be studied or analyzed and is believed to be true and accurate, neither the authors nor the publisher can accept any legal responsibility for any errors, omissions, inaccuracies, or other factors The authors and contributors have taken their best effort to represent the contents

of this book correctly

In preparing this book to ensure its completeness and the correctness of the subjects reviewed, use was made of the authors’ worldwide personal, industrial, and teaching experiences totaling about a century Use was also made of worldwide information from industry (personal contacts, material and equipment suppliers, conferences, books, articles, etc.) and major trade associations The authors have taken their best effort to represent the contents of this book correctly

promotion, advertising, and public relations He handles the design and

production services for a number of consumer and business-to-business accounts

written extensively, developed numerous patents within the polymer related industries, is a participating member of many trade and industry groups, and currently is involved in these areas with PlastiSource, Inc., and Plastics FALLO Received BS in Chemistry from Boston College, MBA at Northeastern University, M.S Plastics Engineering from University of Massachusetts Lowell (Lowell Technological Institute), and Ph.D Business Administration at University of California, Berkeley

2 Plastics Engineered Product Design

11 short to very long service life, degradable to non-degradable,

12 process virgin with recycled plastics or recycled alone,

13 simple to complex shapes including many that are difficult or impossible to form with other materials,

14 breathable film for use in horticulture,

15 heat and ablative resistance,

16 a n d s o o n

There is a plastic for practically any product requirements, particularly when not including cost for a few products One can say that if plastics were not to be used it would be catastrophic worldwide for people, products, communications, and so on with a major economic crisis because much more expensive materials and processes would be used Materials can be blended or compounded to achieve practically any desired property or combination of properties The final product performance is affected by interrelating the plastic with its design and processing method The designer’s knowledge of all these variables is required otherwise it can profoundly affect the ultimate success or failure of a consumer or industrial product When required the designer makes use of others to ensure product success

Plastic plays a crucial and important role in the development of our society worldwide With properties ranges that can be widely adjusted and ease of processing, plastics can be designed to produce simple to highly integrated conventional and customized products While it is mature, the plastics industry is far from having exhausted its product design potential The worldwide plastics industry offers continuous innovations in plastic materials, process engineering, and mechanical engineering design approaches that will make it possible to respond to ever more demanding product applications (Fig 1.1)

Innovation trends emerging in plastics engineering designs are essentially combinations and improvements of different processes, combinations and improvements of different materials, integration of a

wide range of functions within a single product, reduced material consumption, and recyclability of the materials employed At the same time, rising requirements are being placed on design efficiency, product quality, production quality, and part precision, while costs are expected

to be reduced wherever possible This combination of objectives is achievable by factors such as process-engineering innovations that reduce the number of process steps

The basic and essential design exercise in product innovation lies in predicting performances This includes the process of devising a

product that fulfills the total requirements of the end user and satisfies

Figure 1 I Flow-chart from raw materials to products (Courtesy o f Plastics FALLO)

the needs of the producer in terms of a good return on investment (ROI) The product designer must be knowledgeable about all aspects

of plastics such as behavioral responses, processing, and mechanical and environmental load stresses Product loads range from short-time static, such as tensile, flexural, torsion, etc., to long time dynamic, such as

creep, fatigue, high speed loading, motion control, and so on In this

book, plastics design concepts are presented that can be applied to

designing products for a range of behaviors

An inspired idea alone will not result in a successful design Designing

is, to a high degree, intuitive and creative, but at the same time empirical and technically influenced Experience plays an important part

that requires keeping up to date on the endless new developments in materials and processes An understanding of one’s materials and a

ready acquaintance with the relevant processing technologies are

essential for converting an idea to an actual product In addition, certain basic tools are needed, such as those for computation and measurement and for testing of prototypes and/or fabricated products

to ensure that product performance requirement are met A single individual designer may not have all of these capabilities so inputs from

many reliable people and/or sources are required

4 Plastics Engineered Product Design

Inputs from many disciplines, both engineering and non-engineering, may be required when designing a product such as a toy, flexible package, rigid container, medical device, car, boat, underwater device, spring, pipe, building, aircraft, missile, or spacecraft The conception of such products usually requires coordinated inputs from different specialists Input may involve concepts of man-machine interfaces (ergonomics), shape, texture, and color (aesthetics) Unless these are in balance, the product may fail

in the market place The successhl integrated product is the result of properly collecting all of the required design inputs

While plastic product design can be challenging, many products seen in everyday life may require only a practical, rather than rigorous approach They are not required to undergo sophisticated design analysis because they are not required to withstand high static and dynamic loads (Chapter 2) Their design may require only the materials information in conventional data sheets from plastic material suppliers Examples include containers, cups, toys, boxes, housings for computers, radios, televisions, electric irons, recreational products, and nonstructural or secondary structural products of various kinds like the interiors in buildings, automobiles, and aircraft The design engineer will need to know when to use the practical approach, the rigorous approach, or a

combination approach

Plastics do not only have advantages but also have disadvantages or

limitations Other materials (steel, wood, etc.) also suffer with dis- advantages or limitations Unfortunately there is no one material (plastic, steel, etc.) that can meet all requirements thus these limitations

or faults are sometimes referred to incorrectly as disadvantages Note that the faults of materials known and utilized for hundreds of years are often overlooked; the faults of the new materials are often over- emphasized

Iron and steel are attacked by the elements of weather and fire [SlS'C

(1 500"F)I but the common practice includes applying protective coatings (plastic, cement, etc.) and then forgetting their susceptibility

to attack is all too prevalent Wood is a usehl material yet who has not seen a rotted board, wood on fire, etc There is cracked concrete and so

on Rcgardless of these and many other disadvantages, lack of perfection does not mean that any steel, wood, or concrete should not be used The same reasoning should apply to plastics In many respects, the gains made with plastics in a short span of time far outdistance the advances made in these other materials

Recognize that modern design engineering has links with virtually every technical area; material, mechanical, electrical, thermal, processing, and