vii
TABLE OF CONTENTS
CHAPTER
1
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xi
LIST OF FIGURES
xiii
LIST OF ABBREVIATIONS AND SYMBOLS
xv
LIST OF APPENDICES
xvi
INTRODUCTION
1
1.1 Background
1
1.2 Research Statement
4
1.3 Problem Statement
4
1.4 Objective Of Project
4
1.5 Scope Of Project
5
viii
2
LITERATURE REVIEW
6
2.1 Introduction
6
2.2 Plastics Material
7
2.2.1 Injection Moulding Processing Conditions
8
2.2.2 Advantage
8
2.3 Injection Molding
2.3.1 Components
2.3.2
8
9
2.3.1.1 Injection System
10
2.3.1.2 Mold System
11
2.3.1.3 Delivery System
13
Warpage Problem
14
2.4 Product Design
15
2.4.1 Uniform Walls
16
2.4.2 Voids And Shrinkage
19
2.4.3 Warpage
20
2.5 Moldflow
22
2.5.1 The Benefits Of Predictive Analysis
23
2.5.2 Optimize Warpage
24
2.5.3 Reduce Warpage
25
2.5.4 Mould Temperature (°C)
And Melt Temperature
27
2.5.5 Injection Time (S)
28
2.5.6 Packing Pressure (Bar)
29
2.5.6.1 Packing Methods
2.5.7 Packing Time (S)
2.6 Mould Design Software
30
31
31
2.6.1 Easy Interfaces for Mould and Casting 33
2.7 Previous Research
34
2.8 Design of Experiment (D.O.E)
36
2.8.1 When to Apply Design of Experiments 37
ix
2.8.2 What Is A Designed Experiment?
37
2.8.3 What Is A Process Diagram?
38
2.8.4 What Is A Factor?
39
2.8.5 What Is A Response?
40
2.8.6 Planning the Experiment
41
2.8.7 A Process Diagram for Injection
3
Molding Experiment
43
2.8.8 An Orthogonal Array
45
2.8.9 Example Data
49
2.8.10 The Pareto Chart
49
2.8.11 The Main Effects Plot
50
2.8.12 Contour Plot
51
2.8.13 Summary
53
RESEARCH DESIGN
54
3.1 Introduction
54
3.2 Factorial Design
54
3.3 Fractional Factorial Design
55
3.4 Flow Chart of Classical Method
56
3.5 Factor Considered
57
3.5 Experimental Layout
57
3.6 Overall Evaluation Criteria
59
3.7 Methodology
60
3.7.1 Step Of Methodology
3.7.1.1 Step 1 : Product Drawing
60
60
3.7.1.2 Step 2 : Choosing The New Run In
Moldflow
62
3.7.1.3 Step 3 : Mesh Model
63
3.7.1.4 Step 4: Select Best Gate Location
64
3.7.1.5 Step 5 : Selected Analysis Sequence
65
x
4
5
3.7.1.6 Step 6: Selection of Plastic Material
66
3.7.1.7 Step 7: Process Setting
67
3.7.1.8 Step 8: Run the Analysis
67
3.7.1.9 Step 9: D.O.E Analysis
68
RESULT AND ANALYSIS
69
4.1 Introduction
69
4.2 Simulation Results
70
4.3 Individual Response Analysis
73
4.3.1 Warpage
73
4.3.2 Volumetric Shrinkage
79
4.3.3 Sink Index
85
4.3.4 Shear Stress
90
4.4 Multiple Response Analysis
96
4.5 Confirmation Test Run
104
4.6 Mould Design
109
CONCLUSION
110
5.1 Conclusion
110
5.2 Recommendations for Future Work
112
REFERENCES
114
APPENDICES
116
xiii
LIST OF TABLE
Table No.
Title
Page
2.0
Material Properties
7
2.1
Finding of Previous Research
34
2.2
Factor and corresponding level
46
2.3
Design Matrix
47
2.4
Design Matrix
47
2.5
Design Matrix
48
2.6
Completed Data
49
3.1
Selection of the controllable factors and levels
57
3.2
Experiment layout of full factorial designs
58
3.3
Properties of PC/ABS
66
4.1
Selection of the controllable factors and levels
70
4.2
Experimental Plan
71
4.3
Experimental Result
72
4.4
ANOVA table for warpage
74
4.5
Warpage Optimization Data
78
4.6
ANOVA table for volumetric shrinkage
79
4.7
Volumetric Shrinkage Optimization Data
84
4.8
ANOVA table for Sink Index
85
4.9
Volumetric Shrinkage Optimization Data
89
4.10
ANOVA table for Shear Stress
90
xiv
4.11
Volumetric Shear Stress Optimization Data
95
4.12
Data for OEC calculation
96
4.13
Result for OEC
97
4.14
ANOVA table for OEC
98
4.15
OEC Optimization Data
103
4.16
An example of the set goals for OEC Optimization 105
4.17
Possible solutions for OEC Optimization
4.18
An example of output from the point prediction
105
Tool
106
4.19
Analysis of confirmation experiments for OEC
106
4.20
Actual result analysis of confirmation
experiments for OEC
4.21
Analysis of confirmation of experiments for
Warpage
4.22
5.1
107
Analysis of confirmation experiments for
Sink Index
4.24
107
Analysis of confirmation experiments for
Volumetric shrinkage
4.23
106
107
Analysis of confirmation experiments for
Shear Stress
108
Optization of Response by Number of Run
111
xiii
LIST OF FIGURE
No.
Title
Page
1.1
Moldflow Analysis of Injection Moulding Product
3
2.1
Injection Moulding Machine
9
2.2
A single screw injection-molding machine for
11
thermoplastics, showing the plasticizing screw,
a barrel, band heaters to heat the barrel,
a stationary platen, and a movable platen
2.3
A typical (three-plate) molding system
12
2.4
(a) Two-plate mold (b) Three-plate mold
13
2.5
Delivery System
13
2.6
Warping
17
2.7
Transition of Wall Thickness
18
2.8
Coring to Eliminate Sinks
18
2.9
Gusseting to Reduce Warping
19
2.10
Boss Design to Eliminate Sinks
20
2.11
Warpage caused by Non-Uniform Wall Thickness
21
2.12
Moldflow Logo
22
2.13
Filling Analysis
24
2.14
Optimize Warpage
25
2.15
Reducing Warpage
26
2.16
Effect increasing mold temperature
27
xiv
2.17
Packing Method Graph
30
2.18
Pro/Engineer Modelling
32
2.19
Process Diagram
38
2.20
A Process Diagram for an Injection Molding Experiment
44
2.21
Tree Diagram
46
2.22
Example of Pareto Chart
50
2.23
Example of Main Effects
50
2.24
Contour Plot for this example
52
3.1
Flow Chart of DOE Methodology
56
3.2
Formulation of OEC
59
3.3
Laptop Lid Casing
61
3.4
Analysis Methodology Flow Chart
61
3.5
Creating a project name
62
3.6
Selecting the Mesh type
62
3.7
Mesh Window
63
3.8
Mesh Model of Product
64
3.9
Gate Location Window
64
3.10
Analysis Sequence Selection
65
3.11
Selection of Plastic Material
66
3.12
Process Setting Window
67
4.1
Half-Normal % Probability Plot for Warpage
75
4.2
Pareto Chart for Warpage
76
4.3
Interactions factor plot for warpage for BC and BD
77
4.4
Interactions factor plot for warpage for CD
77
4.5
Half-Normal % Probability Plot for Vol. Shrinkage
81
4.6
Pareto Chart for Volumetric Shrinkage
82
4.7
Main effect interaction plot of BC and BD
83
4.8
Main effect interaction plot of CD and CE
80
4.9
Main effect interaction plot of DE
80
4.10
Half-Normal % Probability Plot for Sink Index
86
4.11
Pareto Chart for Sink Index
87
xv
4.12
Main effect interaction plot of BD and BE
88
4.13
Main effect interaction plot of DE
88
4.14
Half-Normal % Probability Plot for Shear Stress
92
4.15
Pareto Chart for Shear Stress
93
4.16
Main effect interaction plot of BC
93
4.17
Main effect interaction plot of CD and CE
94
4.18
Half-Normal % Probability Plot for OEC
100
4.19
Pareto Chart for OEC
101
4.20
Main effect plot of D and E
101
4.21
Main effect interaction plot of BC
102
xv
LIST OF ABBREVIATIONS AND SYMBOLS
PC/ABS
-
Polycarbonate-Acrylonitrile-Acrylonitrile-Butadine-Styrene
ANOVA
-
Analysis of variance
CAD
-
Computer aided design
CAE
-
Computer aided engineering
C.I.
-
Confidence interval
Deg.
-
Degree
DOE
-
Design of experiment
OEC
-
Overall evaluation criteria
P.I.
-
Prediction interval
Pro-E
-
Pro-Engineer
QC
-
Quality characteristic
SE
-
Standard deviation
Sec.
-
Seconds
W
-
Weighting
|x|
-
Absolute value for reading
XA… XD
-
Sample Reading Value of response
XA1… XD1
-
Worst reading value of response
XA2… XD2
-
Best reading value of response
Y
-
Response
α
-
Alpha phase
xvi
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A-1
Result of Warpage
116
A-2
Result of Volumetric Shrinkage
116
A-3
Result of Sink Index
117
A-4
Result of Shear Stress
117
A-5
Moldflow Log file
118
B-1
Core and Cavity Insert
119
B-2
Mould Design
119
B-3
Mould Opening
120
B-4
Mould Assembly Drawing
121
C-1
Schedule for Project
122