iv
TABLE OF CONTENTS PAGE
DECLARATION DEDICATION
ABSTRACT
i ABSTRAK
ii ACKNOWLEDGEMENTS
iii TABLE OF CONTENTS
iv LIST OF TABLES
vi LIST OF FIGURES
viii LIST OF APPENDICES
xi LIST OF ABBREVIATIONS
xii LIST OF PUBLICATIONS
xiii CHAPTER
1. INTRODUCTION
1
1.1 Background 1
1.2 Problem Statement 4
1.3 Objectives 6
1.4 Scope 6
1.5 Thesis Outline 7
2. LITERATURE REVIEW
9 2.1 Injection Moulding
9
2.1.1 Application 9
2.1.2 Process 10
2.2 Injection Moulding Parameters 13
2.2.1 Melt Temperature 18
2.2.2 Mould Temperature 19
2.2.3 Cooling Time 20
2.3 Mould 21
2.3.1 Types of Mould 22
2.3.2 Feeding System 24
2.3.3 Mould Components 25
2.3.4 Cooling Medium 26
2.4 Plastic Defect 26
2.4.1 Warpage Defect 26
2.5 Plastic Material 28
2.5.1 Polypropylene PP 31
2.6 Computer Aided Engineering CAE Simulation 32
2.6.1 Product Design 33
2.6.2 Meshing 33
2.6.3 Cooling System 34
2.6.4 Warpage Analysis 35
2.7 Design of Experiment DOE 37
2.7.1 Taguchi Method 38
2.7.2 Application of Taguchi Method 43
v 2.8 Analysis of Variance ANOVA
45 2.9 Summary
46
3. METHODOLOGY
47
3.1 Introduction 47
3.2 Equipment, Tool and Material 49
3.2.1 Machine 49
3.2.2 Mould 50
3.2.3 Plastic Material 52
3.2.4 Warpage Measurement 53
3.2.5 Mould Temperature Controller 55
3.2.6 Mould Temperature Measurement 57
3.3 Software 59
3.3.1 Minitab
TM
Version 15 59
3.3.1 Moldflow
TM
Plastic Insight MPI 59
3.4 Experimental Setup 60
3.4.1 Planning Matrix for Mould Temperature Gradient 62
3.4.2 Planning Matrix for Cold Mould 63
3.4.3 Planning Matrix for Hot Mould 65
3.5 Warpage Analysis Using Moldflow
TM
Plastic Insight MPI 66
3.6 Summary 69
4. RESULT AND DISCUSSION
70
4.1 Framework of Discussion Result 70
4.2 Product Pre-Simulation and Meshing Statistics 73
4.3 Mould Temperature Gradient Simulation 77
4.3.1 Taguchi Analysis for Mould Temperature Gradient 81
4.3.2 Analysis of Variance ANOVA for Mould Temperature Gradient
84 4.3.3 Interaction Plot for Mould Temperature Gradient
85 4.3.4 Comparison between Simulation and Experiment
86 4.4 Cold Mould Temperature Simulation
88 4.4.1 Taguchi Analysis for Cold Mould
90 4.4.2 Analysis of Variance ANOVA for Cold Mould
94 4.4.3 Interaction Plot for Cold Mould
94 4.5 Hot Mould Temperature Simulation
95 4.5.1 Taguchi Analysis for Hot Mould
97 4.5.2 Analysis of Variance ANOVA for Hot Mould
101 4.5.3 Interaction Plot for Hot Mould
101 4.6 Summary
104
5. CONCLUSION AND RECOMMENDATIONS
