ix
LIST OF FIGURE
2.1 Electron configuration 4
2.2 Deformation of material in machining 10
2.3 Orthogonal cutting system 12
2.4 Oblique cutting system 13
2.5 Milling process on job part 14
2.6 Different Types of Peripheral Milling 15
2.7 Conventional Face Milling 16
2.8 Partial Face Milling 17
2.9 End Milling 17
2.10 Profile Milling 18
2.11 Pocket Milling 18
2.12 Surface Contouring 18
2.13 CNC Milling Machine 23
2.14 Coordinate System used in CN for Flat and Rotational Work 24
2.15 Definition of roughness average 29
2.16 Surface damage when a worn tool is used under dry-cut conditions 31
2.17 Plastic deformation at the cutting tool edge The white dashed line is the original tool profile
32
2.18 The microhardness value measured beneath the machined surface 33
2.19 Effects of elevated temperature on strain hardened materials when machining
34
3.1 Research methodology 38
3.2 Aluminium LM6 in ingot shape 41
3.3 High speed steel cutting tool 41
3.4 Uncoated carbide cutting tool 42
3.5 Haas’ 3 axis CNC vertical milling machine 43
x 3.6 Surface roughness tester Mitutoyo SJ-301
44 3.7 Mitutoyo microhardness testing machine
45 3.8 Scanning electron microscope SEM
46 3.9 Surface grinding and polishing machine
47 3.10 Grinding paper
47 3.11 Etching solution for aluminium alloy
48
4.1 Microstructure of aluminium LM6 51
4.2 Cutting parameter experiment design 53
4.3 Surface profile using high speed steel 55
4.4 Surface profile using uncoated carbide 56
4.5 Graph for surface roughness versus radial depth of cut 59
4.6 Graph for time versus radial depth of cut 59
4.7 Microstructure when aluminium LM6 machine 61
4.8 Microstructure when aluminium LM6 machine with uncoated carbide 62
4.9 Hardness value after machining aluminium LM6 63
xi
LIST OF ABBREVIATIONS, SYMBOLS AND NOMENCLATURE
Al -
Aluminium CNC
- Computer Numerical Control
MMC -
Metal matrix composites CM
- Centimetre
MM -
Milimeter -
More than σ
- Stress
τ -
Torque d
- Diameter of milling cutter in mm
V -
Cutting speed linear in meter per minute N
- Cutter speed in revolution per minute
Ra -
Roughness average Rv
- Maximum depth
Rp -
Maximum height Rt
- Total height
BUE -
Built-up edge SEM
- Scanning Electron Microscope
xii Min
- Minutes
Kg -
Kilogram
1
CHAPTER 1
INTRODUCTION
1.1 Background
Machining is a chip removal process to form a shape by using a specific machine. Machining is used because it has a high accuracy. By using this machine will also
save time and production will rise higher. Machining refers to several processes such as sawing, drilling, boring, Shaping, reaming and others. There are various
types of machining in manufacturing which lathe machine, milling machine, drill machine Presses and so on. Nowdays, a used machine is in automatic form. It is
controlled by a computer program called numerical control CNC. CNC is a command-based coordinate to get a form for you automatically Kalpakjian 2006.
Physically, chemically and mechanically aluminium is a metal like steel, brass, copper, zinc, lead or titanium. It can be melted, cast, formed and machined much
like these metals and it conducts electric current. In fact often the same equipment and fabrication methods are used as for steel Boyer 2006. Pure aluminium is a
weak, very ductile, material. The mechanical properties depend not only on the purity of the aluminium but also upon the amount of work to which it has been
subject. A range of tempers is thus produced by different amounts of work hardening. It has an electrical conductivity about two-thirds that of copper but
weight for weight is a better conductor. One of the most common end users of aluminium is packaging, including drinks cans, foil wrappings, bottle tops and
foils containers Forbes 2001. Each of these relies on aluminium to provide a way of containing the food cleanly, and to protect it from changes in the local
environment outside the packaging. Aluminium natural resistance to corrosion aids it in its role in packaging. Aluminium unbeatable strength to weight ratio
2
gives it many uses in the transport industry. Aluminium is so lightweight this means that less energy needs to be used to move a vehicle made with aluminium
than one made from a heavier metal. Aluminium is also vital in power lines, the building and construction industry and commonplace household objects. The key
features that lend aluminium to these uses are corrosion resistance, low density, ductility, electrical conductivity and strength in alloys Davyson 2002.
Aluminium not only offers many advantages due to its material properties. Aluminium is also extensively adaptable to fabrication and machining processes.
Aluminiun be used because aluminum is a very light metal. Aluminium also naturally generates a protective oxide coating and is highly corrosion resistant.
Aluminium is an excellent heat and electricity conductor and in relation to its weight is almost twice as good a conductor as copper. This has made aluminium
the most commonly used material in major power transmission lines. Aluminium is a good reflector of visible light as well as heat, and that together with its low
weight, makes it an ideal material for reflectors in and aluminium also ductile and has a low melting point and density Davyson 2002.
One of the common aluminium alloys is aluminium LM6. Aluminium LM6 is a high purity alloy, which is used in castings where thinner more intricate sections
are required. Aluminium LM6 contains of copper, magnesium, silicon, iron, manganese, nickel, zinc, lead, tin, titanium and aluminium.
This alloy has medium strength with excellent ductility but suffers a rapid loss of properties at elevated
service temperatures Sayuti 2008.
There is established study of machinery aluminium LM6 particularly in machining process. Many researcher have report that the characteristic of
machinery of this material in turning process. However, there is limitation knowledge about machining aluminium LM6 especially in milling operation and
by using the commercial cutting tool such as high speed steel and uncoated carbide. Milling process is important to produce a flat shape such as flat bar, vise
and many more Joardar 2011. Therefore the study of milling aluminium LM6 tends to investigate the machinability of aluminium LM6 in term of the cutting
tool, the cutting parameters and the surface integrity. This report will focus more
3
into surface integrity such as surface roughness, surface microhardness, subsurface micro structure and surface profile when machining aluminium LM6
using high speed steel and uncoated carbide cutting tools.
The research will create knowledge of machining characteristic of aluminium LM6. It will be beneficial in terms surface to the machinist whenever they want
performing milling. The research also will provide useful information about suitable parameters to machinery aluminium LM6.
1.2 Objective
