vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xi
LIST OF SYMBOLS
xv
LIST OF APPENDICES
xvi
INTRODUCTION
1
1.1
Background
1
1.2
Problem Statement
3
1.3
Objective of the Study
4
1.4
Significance of the Study
5
1.5
Scope of Study
6
1.6
Overview of the Methodology
7
1.7
Thesis Organization
8
LITERATURE REVIEW
9
2.1
Theory of Metal Cutting
9
2.1.1 Orthogonal Cutting
11
2.1.2 Oblique Cutting
12
Metal Cutting in Turning Operation
12
2.2
viii
2.3.
Tool Geometry
13
2.4
Turning Cutting Data
15
2.5
Boring Operation
18
2.6
Cutting Forces in Boring Operation
19
2.7
Holding the Boring Bar
21
2.8
Surface Roughness in Turning
25
2.9
Factors Affecting Surface Roughness
27
2.9.1 Nose Radius
26
2.9.2 Feed Rate
28
2.9.3 Depth of Cut
28
2.9.4 Cutting Speed
28
2.9.5 Built-Up Edge
29
2.9.6 Material Side Flow
28
2.9.7 Chip Morphology
30
2.10
Wear Mechanism
30
2.11
Chip Formation
33
2.12
Literature Review on Surface Roughness in
36
Turning Operation
2.13
3
Summary of Literature Review
44
METHODOLOGY
45
3.1
Introduction
45
3.2
Research Methods and Procedure
46
3.3
Machines and Equipment
47
3.4
Measurement Equipment and Setup
49
3.4.1 Surface Roughness Measurement
49
3.4.2 Tool Wear Measurement
51
3.5
Workpiece Material
53
3.6
Tool Cutting Material
55
3.7
Machining Parameters
57
3.8
Cutting Condition
57
3.9
Workpiece Preparation
58
3.10
Measure Surface Roughness
60
3.11
Analyze of Tool Wear
61
ix
3.12
Analyze of Chips Formation
62
3.13
Experimental Design
62
3.13.1 Test for Significance of the Regression Model
65
3.13.2 Test for Significance on Individual Model
65
Coefficient
3.13.3 Test for Lack-of-Fit
4
5
6
66
EXPERIMENTAL RESULTS
68
4.1
Introduction
68
4.2
Experimental Results
70
4.3
ANOVA Analysis
71
4.3.1 Confirmation Run
81
4.3.2 Optimization in Range of Surface Roughness
82
4.4 Tool Wear Mechanism
84
4.5 Chip Formation
88
DISCUSSION
94
5.1
Introduction
94
5.2
Surface Roughness in Turning Boring Operation
95
5.3
Tool Wear Mechanism
98
5.4
The Effect of Tool Wear on the Surface Roughness
101
CONCLUSION AND RECOMMENDATIONS
REFERENCES
Appendices A - C
102
105
108 - 118
x
LIST OF TABLES
TABLE NO.
2.1
TITLE
PAGE
Summary of finding related to the boring operation
41
and surface roughness
3.1
Typical composition of aluminium alloy 6061
54
3.2
Physical properties of pluminium alloy 6061
54
3.3
Mechanical properties aluminium alloy 6061
54
3.4
Machining parameter
57
3.5
Level of independent variables
58
4.1
Experimental plan for surface roughness by turning
69
boring operation
4.2
Experimental result of surface roughness by turning
70
boring operation
4.3
ANOVA table for surface roughness
71
4.4
Experimental plan for confirmation run
81
4.5
Result of conformation test
81
4.6
Experiment plan for optimization test
83
xi
LIST OF FIGURES
FIGURE NO .
TITLE
PAGE
2.1
Basic machining operation and important parameter
10
2.2
Cutting process, (a) Orthogonal cutting (b) Oblique cutting
11
2.3
Conventional lathe machine
13
2.4
Turning tool nomenclatures
14
2.5
The main cutting data/tool elements for turning tool
applications
17
2.6
Internal turning operation
19
2.7
Radial and tangential cutting forces deflect the boring bar
during machining, often necessitating cutting edge
compensation and tool damping.
20
2.8
The way a boring bar is clamped is decisive as regards
performance and result
23
2.9
Solid bars overhang
23
2.10
Chip evacuation is a critical factor for successful boring.
24
2.11
Tool wear phenomena
32
2.12
Features of single-point wear in turning. (ISO proposed
standard)
33
2.13
Three basic types of chips
34
2.14
Chips are broken (a) on their own (b) against the tool (c)
against workpiece
35
2.15
Chip formation varies with depth of cut, entering angle,
feed, material and tool geometry
35
3.1
Overall research methodology
46
xii
3.2
An internal turning setup with a workpiece clamped in a
shuck to the left and a boring bar clamped in a clamping
housing to the right
47
3.3
Machine CNC Turning DMG CTX 310
48
3.4
Surface roughness tester
50
3.5
Measuring setup
50
3.6
Optical Nikon microscope c/w Image analyzing software
51
3.7
Optical 3D measurement Infinite Focus
52
3.8
Solid steel boring bar with cermet insert
55
3.9
Cermet insert Specification
55
3.10
Boring bar specification
56
3.11
U-drill and insert specification
56
3.12
Dimension of workpiece before experiment cut
59
3.13
View of boring operation on a workpiece
59
3.14
Machining the workpiece
60
3.15
Surface roughness measurement of work sample
61
4.1
Normal probability plots of residuals for surface
finish in turning boring operation.
73
4.2
Plots of residuals vs. predicted response for
surface finish in turning boring operation.
74
4.3
Outlier T plot for surface finish in turning boring
operation.
74
4.4
Cutting speed factor influence on Ra in turning
boring operation
76
4.5
Feed rate factor influence on Ra in turning boring
operation
76
4.6
Boring bar length factor influence on Ra in turning
boring operation
76
4.7
Boring bar diameter factor influence on Ra in turning
boring operation
77
xiii
4.8
Influence of interaction machining parameters on Ra
in turning boring operation.
78
4.9
Perturbation graph for Ra in turning boring
operation. (bd = 12 mm)
78
4.10
Perturbation graph for Ra in turning boring operation.
(bd = 16 mm)
79
4.11
Surface and contour plot on Surface finish
80
4.12
Plot for optimum cutting parameter in range.
83
4.13
Initial tool wear for boring bar Ø16 mm with tool
overhang 55 mm.
85
4.14
Initial tool wear for boring bar Ø16 mm with tool
overhang 60 mm.
85
4.15
Initial tool wear for boring bar Ø16 mm with tool
overhang 65mm.
86
4.16
Initial tool wear for boring bar Ø12 mm with tool
overhang 55mm.
86
4.17
Initial tool wear for boring bar Ø12 mm with tool
overhang 65mm.
87
4.18
Initial tool wear for boring bar Ø12 mm with tool
overhang 60mm.
87
4.19
ISO-based chip forms classification
88
4.20
Chips formation using bar diameter 16 mm,
bar length 55 mm.
89
4.21
Chips formation using diameter 16 mm, bar length 65mm.
90
4.22
Chips formation with cutting data Diameter 12 mm,
Bar length 55 mm
91
4.23
Chips formation using Diameter 12, Bar length 65
92
4.24
Chips formation using bar length 60
93
5.1
Surface finish result using cutting data cs=150 m/min,
f=0.1 mm/rev, doc = 0.1 mm, bd=16 mm, bl=55 mm.
97
5.2
Surface finish result using cutting data cs=250 m/min,
f=0.2 mm/rev, doc = 0.25 mm, bd=12 mm, bl=655 mm.
97
xiv
5.3
Material stick on top face insert
99
5.4
Built up edge on rake side
100
5.5
Crater wear on rake side
100
5.6
Marks on surface finish cause of material adhered on to the
tool continuously ploughed on the machined surface
101
xv
LIST OF SYMBOLS
ANOVA
-
Analysis of Variance
Al
-
Aluminium
ECEA
-
End Cutting Edge Angle
SCEA
-
Side Cutting Edge Angle
Sqrt
-
Square root
doc
-
Depth of Cut
cs
-
Cutting Speed
f
-
Feed rate
bd
-
Bar Diameter
bl
-
Bar Length
F
-
Force
Fc
-
Cutting Force
Ft
-
Tangential Force
Fr
-
Radial Force
N
-
Revolution per Minute
Ra
-
Surface Roughness
T
-
Tool Life
V
-
Cutting Speed
C
-
Taylor’s constant
n
-
Taylor’s exponential
α
-
Rake Angle
Ø
-
Diameter
ʋ
-
Cutting Velocity
xvi
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A-1
Unmodified ANOVA table for turning boring operation
105
B-1
Box-cox plot for turning boring operation
106
B-2
Initial tool wear for cutting Al 6061, times 6s.
107
B-3(a)
Surface finish after turning boring operation sequence
108
followed experimental plan
B-3(b)
Surface finish after turning boring operation sequence
109
followed experimental plan
B-4
Result of chip formation
110
C-1
Chip formation chart
111
C-2
Recommendation of tool overhang for internal turning
112
C-3
Factor that effect vibration tendencies positively and
113
negatively, vibration tendency grow towards the right
C-4(a)
Table of tool wear
114
C-3(b)
Table of tool wear
115