vii
TABLE OF CONTENTS
CHAPTER 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
1 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
2 LITERATURE REVIEW 9
2.1 Theory of Metal Cutting 9
2.1.1 Orthogonal Cutting 11
2.1.2 Oblique Cutting 12
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 Summary of Literature Review 44
3 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
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 66
4 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
5 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
6 CONCLUSION AND RECOMMENDATIONS 102
REFERENCES 105
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 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
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
3.2 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
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.
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
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
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
followed experimental plan
108
B-3(b) Surface finish after turning boring operation sequence followed experimental plan
109
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
negatively, vibration tendency grow towards the right
113
C-4(a) Table of tool wear 114
