Depth of cut analysis using plasma cutter for hybrid machine innovation.
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
DEPTH OF CUT ANALYSIS USING PLASMA CUTTER FOR
HYBRID MACHINE INNOVATION
This report submitted in accordance with requirement of the Universiti Teknikal
Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Manufacturing Process) (Hons.)
by
WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
B051010224
881211035151
FACULTY OF MANUFACTURING ENGINEERING
2014
DEPTH OF CUT ANALYSIS USING PLASMA CUTTER
FOR HYBRID MACHINE INNOVATION
WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
B051010224
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2014
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: Depth Of Cut Analysis Using Plasma Cutter For Hybrid Machine
Innovation
SESI PENGAJIAN: 2013/14 Semester 2
Saya WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti
Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis.
2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja dengan izin penulis.
3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan
pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan ( ./')
D
SULIT
(Mengandungi maklumat yang berdarjah keselamatan
atau kepentingan Malaysia sebagaimana yang termaktub
dalam AKTA RAHSIA RASMI 1972)
D
TERHAD
(Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan)
D
Tl OAK TERHAD
Disahkan oleh:
ｾ＠ . Me•L
Cop
Alamat Tetap :
5631-W Jin Kbn Sultan
.Ak. .
Pensyarah Kanan
R asnilt :Kejuruteraan Pembuatal'l
•Jnlversiti Tekn1kal Malaysia Melaka
Hang 1 uah Java
7f. 1 CV' Durian i ·'Jngqal, M
Kampung Dusun Raja
15300 Kata Bharu, Kelantan
Tarikh:
IJ- /
G
( JO I 'I
** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi
berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai
SULIT atau TERHAD.
© Universiti Teknikal Malaysia Melaka
DECLARATION
I hereby, declare this report entitled "DEPTH OF CUT ANALYSIS USING
PLASMA CUTTER FOR HYBRID MACHINE INNOVATION" is the results of my
own research except as cited in references
Signature
Author's Name
Date
/2
JUNE 2014
© Universiti Teknikal Malaysia Melaka
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM
as a partial fulfillment of the requirements for the degree of Bachelor of
Manufacturing Engineering (Manufacturing Engineering) (Hons.). The member
of the supervisory is as follow:
｣ ｱＬ
ｾ＠
ｩｬｂｺｾ＠
ｾ Ｑ ｗ ａ ｾｂｬｩＳ
ｫ ｰ ｡ｲＩ＠
Pensyarah Kanan
ｾ ｡ｲｵｴ＠
Kejurut91"aan Pembuatan
•Jnlversiti Tekn1kal Malaysia Melaka
Hang 1 uah Java
M
1-t\tl\" Ourian ｬｾｧＮｑ｡Ｌ＠
© Universiti Teknikal Malaysia Melaka
ABSTRAK
Pada zaman moden sekarang, terdapat perningkatan penyelidikan dalam pemesinan dan
penerokaan dalam inovasi teknologi. Salah satu kejayaan penyelidikan adalah mesin
hibrid iaitu di mana gabungan dua atau lebih proses dalam sebuah mesin. Peningkatan
persaingan dalam industri untuk mencapai kejituan yang tinggi selain kepercayaan
dalam permesinan, mesin konvensional menjadi nadi dalam pelbagai industri. Proses
konvensional yang selalu diketengahkan adalah Pemotongan Secara Plasma Udara.
Kadar kejituan produk akhir dan kebolehan untuk memotong pelbagai bahan yang keras
dan dapat membentuk rekabentuk yang komplek untuk memenuhi permintaan pasaran.
Berdasarkan kajian terdahulu dalam tesis ini telah menganalisis rangka kerja untuk
memaksimumkan keputusan, kaedah separa two factorial telah digunakan untuk tujuan
tersebut. Siri orthogonal yang sesuai telah diputuskan berdasarkan bilangan parameter
dan terdapat peringkat yang melaksanakan bilangan ujian yang minimum. Bahan kerja
Ameriacan Iron and Steel Institute (AISI) D2 iaitu besi bahan kerja digunakan untuk
tujuan ujikaji. Nilai yang terbaik diputuskan dengan menggunakan plot perkadaran yang
utama dan jadual analisis perbezaan (ANOVA). Persamaan regrasi untuk kedalaman
potongan telah dihasilkan melalui perisian Design Expert 7.0. Ujikaji pengesahan untuk
kedalaman potongan telah dijalankan dan keputusan ujikaji yang diberikan untuk
mengesahkan keberkesanan perdekatan ini dengan kedalaman pemotongan sebanyak
4.625mm dengan ralat yang diterima adalah dibawah 10%. Persamaan antara model
berangka peringkat pertama yang dihasilkan dalam projek dengan keputusan ujikaji ini
untuk Jarak pemotongan menggunakan pemotongan secara Plasma adalah 96.7 % dan
persamaan ini dapat digunapakai dalam menjimatkan kos dan masa proses pemotongan.
i
ABSTRACT
Within modern age, there is huge investigation in machining and exploration in
innovation of technology. On the list of successful project is hybrid machine within the
combination of two or more process in single machine. The increasing of competition in
industry and on order to achieve high precision and reliability, today the nontraditional
machining are become lifeline of almost any industry. The most essential nontraditional
machining approaches are Air Plasma Machining. Its finishing, high precision, the
capability to cut variety hard materials and to create complex design raises the need in
industry. Throughout thesis literature review has been analyzed in framework to
parametric optimization of Air Plasma Cutting Machine. In order to achieve target and
optimum results, two level factorial method utilized. The suitable orthogonal array has
been decided according to number of parameter and there levels to execute minimum
testing. The work pieces of American Iron and Steel Institute (AISI) D2 tool steel
materials were used for experiment purpose. The best possible value has been decided
with by using major influence plot and ANOVA table. The Regression equation for
distance of cut has been developed with the help of Design Expert 7.0 Software.
Verification experiments have done to verify the value predicted throughout software.
The verification for Distance of cut run has been carried and experimental results are
provided to confirm the effectiveness of this approach, the DOC value was 4.625mm.
Error within 10 % was allowed, where the similarity between model and experimental
result is 96.7%, the conclusion that, this model can used for reduce the process time and
cost
ii
DEDICATION
For my beloved mother, lecture, friend and also to everyone who were with me all the
time
iii
ACKNOWLEDGEMENT
Alhamdulillah and grateful to ALLAH S.W.T for giving me the strength, patience and
perseverance in completing the Final Year Project
I would like to express my deep sense of respect and gratitude toward my supervisor Dr
Mohd Hadzley bin Abu Bakar, who not only guided the academic/final year project
work but also stood as a teacher and philosopher in realizing the imagination in practical
way, I want to thank him for introducing me for the field of Optimization and giving the
opportunity to work under him. His optimism has provided an invaluable influence on
my career and outlook for the future. I consider it my good fortune to have got an
opportunity to work with such a wonderful person.
I am especially indebted to my mother for their love, sacrifices and support. They are my
teachers after I came to this world and have set great example for me about how to live,
study and work. Also would like to convey my biggest thanks to all the Faculty of
Manufacturing Engineering, University of Technical Malaysia Melaka staff for their
encouragement to supporting me throughout my project.
I also responsible to all people who have been directly and indirectly involved through
contributing ideas and materials and professional opinion.
iv
TABLE OF CONTENT
Abstrak
i
Abstract
ii
Dedication
iii
Acknowledgement
iv
Table of content
v
List of table
viii
List of figure
ix
CHAPTER 1 : INTRODUCTION
1.1
Introduction
1
1.2
Process Description
2
1.3
Problem Statements
4
1.4
Objectives
6
1.5
Scope of project
6
CHAPTER 2 : LITERATURE REVIEW
2.1
Introduction
7
2.2
AISI D12 Carbon Steel
7
2.2.1
8
2.3
Milling Machine
2.3.1
2.4
2.5
Application of AISI D2
9
Milling Machining Operation
12
2.3.1.1 End Milling
12
Cutting Tools.
13
2.4.1
Carbides (uncoated tool)
13
2.4.2
Coated carbide (coated tool)
14
Milling Parameter
15
v
2.5.1
Cutting Speed
16
2.5.2
Feed Rate
16
2.6
Plasma Cutting
17
2.7
Principle Of Plasma Arc Cutting
18
2.8
Plasma Cutting Capability
22
2.9
System
23
2.10
The Process of Air Plasma Cutter
24
2.11
Air Plasma Cutter Parameter
25
2.11.1 Current Flow Rate
25
2.11.2 Feed Rate
25
2.11.3 Standoff height
26
Plasma Torch
26
2.12.1 Torch Stand Off
27
2.12.2
Torch Designs
28
2.21.3
Torch Consumables
28
2.12.5
Swirl/Ceramic Ring.
29
2.12.6
Tip
30
2.12
2.13
Surface Integrity
30
2.13.1 Surface Topography
32
2.13.1.1 Surface Roughness
2.14
2.15
33
2.13.2 Surface metallurgy
37
Design Of Experiments (DOE)
38
2.14.1
40
2-Level Factorial Design
Laser Machining
40
CHAPTER 3: METHODOLOGY
3.1
Introduction
41
vi
3.2
Define The Objective Of The Experiment
41
3.3
Jig Design
42
3.4
Determine the Input Parameters at Low Level and High Level
44
3.5
Design of Experiment Matrix
44
3.6
Identify the Appropriate Response Variable
45
3.7
Preparation of the Experiment
45
3.7.1
Workpiece Preparation
45
3.7.2
Haz 2 Mini Vertical Machining Centre
46
3.8
Conclusion and Recommendation
47
3.9
Flow Chart of Study
48
CHAPTER 4 : RESULT AND DISCUSSION
4.1
Finish Jig Part
49
4.2
Experiment Layout
53
4.3
The Effect of the parameter on Distance off cut
54
4.3.1
Cutting Current
54
4.3.2
Feed Rate
57
4.3.3
Air Pressure
59
4.4
Analysis Of Variance (ANOVA)
61
4.5
Verification Test
62
4.6
Discussion
64
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1
Conclusion
65
5.2
Recommendation
66
REFERENCE
67
APPENDICES
70
vii
LIST OF TABLE
Table 2. 1 Element in AISI D 12
8
Table 2. 2 Properties table of AISI D2
8
Table 2. 3 CNC machine criteria
9
Table 3. 1 Variable factor level
44
Table 3. 2 Design Matrix generated by Design Expert 7.0 software
44
Table 3. 3 Mechanical Properties of work material
46
Table 3. 4 Chemical composition and hardness of AISI D2
46
Table 4. 1 Value of variable at different level
53
Table 4. 2 Experimental Layout for Distance of cut
54
Table 4. 3 ANOVA table for Distance of Cut
61
viii
LIST OF FIGURE
Figure 1.1 Plasma Jet
3
Figure 1.2 TIG and Plasma Arcs
4
Figure 2.1 CNC Milling Machine.
11
Figure 2.2 End milling
12
Figure 2.3 Usual carbide inserts with several shapes
15
Figure 2.4 The principle of the plasma cutting
19
Figure 2.5 Air Plasma
22
Figure 2.6 Air Plasma Setup
23
Figure 2.7 Air Plasma Cutter System
24
Figure 2.8 Torch Stand Off
27
Figure 2.9 Torch Breakdown
28
Figure 2.10 Electrode
29
Figure 2.11 Swirl Ring
29
Figure 2.12 Tip
30
Figure 2.13 The six clusters of important issues that explain the surface integrity of a
complete material
31
Figure 2.14 3D surface of machined workpice
32
Figure 2.15 Surface texture
33
Figure 2.16 Schematic section through a machined surface
37
Figure 3.1 Part 1
42
Figure 3.2 Part 2
42
Figure 3.3 Part 3
43
Figure 3.4 Part 4
43
Figure 3.5 Complete Assembly Jig
43
ix
Figure 3.6 Flow chart of the workpiece preparation
45
Figure 3.7 HAZ2 hybrid mini Machine Centre
46
Figure 3.8 Experiment Flowchart
47
Figure 4.1 Full assembly Jig
49
Figure 4.2 Part 1
50
Figure 4.3 Part 2
51
Figure 4.4 Part 3
51
Figure 4.5 Plasma Torch clamper
52
Figure 4.6 Complete Assembly jig attach to HAZ2 CNC Mini Milling Machine
52
Figure 4.7 Correlation between cutting speed and energy density
55
Figure 4.8 The relationship between current and DOC
55
Figure 4.9 The effect of parameter current on Distance of cut
56
Figure 4.10 The different between current 30 ampere and 20 ampere
56
Figure 4.11 Molten metal for low and high feed rate
57
Figure 4.12 The effect of feed rate on Distance Of Cut
57
Figure 4.13 Diagram for increasing and decreasing feed rate
58
Figure 4.14 The effect of parameter air pressure on Distance of cut
59
Figure 4.15 Different effect of changing Air pressure on Distance of cut
59
Figure 4.16 3D relationship graph
60
Figure 4.17 The different value between experimental value and theory value.
63
x
CHAPTER 1
INTRODUCTION
1.1
Introduction
Topic of this thesis writing is analysis of the surface integrity by using a plasma cutting
for the hybrid machine technique. The focus of this project is keen to obtain an optimum
condition (setting) and also to obtain maximum Distance Of Cut (DOC).
The result of the electrical arcs when air plasma is heating air to a high temperature to
ionize its atoms (the result is due to an unequal number of electron to protons to an equal
temperature an electrically is charged) and allowing it to conduct electricity. The light
will be produced by a fluorescent lamp when you are reading by lights where you see
plasma in action and containing of low pressure mercury within the shinning tube of the
lamp. A across electrodes with a high voltage that is ionized at the ends of the tube
conducts an electric current which result the plasma to radiate which in turn causes the
phosphor coating on the inner surface of the tube to glow (Miller, 2013) .
Oxy-acetylene cutting repeatedly is the process of selecting fast cutting over steel plate
in many years. The using of the plasma cutting has an attractive much full over, for the
some good reasons to perhaps a most vital for many years. Electrical conductive that is
1
an electrical metal such as stainless steel, aluminum; copper, brass etc will be cut by
plasma cutter.
The cutting that is hotter and tighter than an oxy-acetylene flame is ensured by the
plasma jet which gave kerfs width smaller with a cleaner cut. Compare with oxyacetylene the plasma cutting mainly suitable for cutting a sheet metal and meanwhile a
task the oxy-acetylene cutting torch is not mostly well-suited for since it leaves a lot of
slag on the edges. Moreover the particularly tight focus of the plasma arc tends to reduce
heat distortion in the cut parts.
For reaching high quality, in term of work piece dimensional accuracy, surface finish,
high production rate, less wear on the cutting tools, economy of machining in terms of
cost saving and increase of the product performance with reduced environmental impact
are the challenges that mostly focused with. End milling is the ability to control the
process for a better quality of the final product that is very commonly used and very
high importance for machining process in machining industry.
Hardened steels are substantial in reducing machining costs and lead times compared to
more traditional machine route which benefits in the manufacture of components
(Koshy, 2002). AISI D tool steel group is extensively used in making molds and dies,
but the machine ability of this group is very poor indeed.
1.2
Process Description
Plasma cutting is the process used to cut steel and other metals (or sometimes other
materials) by using a plasma torch. In this process an inert gas (in some units,
compressed air) is blown at high speed out of a nozzle and at the same time an electrical
arc is formed through that gas from the nozzle to the surface that has being cut and
turning some of that gas to plasma. Plasma is used for welding and other applications
2
due to it is sufficient hot to melt the metal that has being cut and also fast to blow molten
away from the cut (Sacks, 2005).
Figure 1.1- Plasma Jet
Space or area surrounding the circumference of the electrode that air plasma has
between the inside circumference of the torch tip or nozzle is the chamber where the air
heated and ionized and heating that cause air greatly expand in volume and pressure.
With a very high speed of temperatures; up to 16,000 degrees C and 6000 m/s air exits
from the constricting orifice of the torch nozzle or tip. The intensity and velocity of the
plasma are determined by a several variables including the type of gas, its pressure &
volume, the flow pattern, the amount of electric current, the size and shape of the
constricting tip or nozzle orifice, and the tip to work distance.
3
Figure 1.2 - TIG and Plasma Arcs
High temperature, constricted, high velocity jet of ionized gas exiting from the
constricting orifice of the torch tip to melt a much localized area and remove the molten
material from the metal being cut by the force of the plasma jet are where the APC
process is used. This process is happened when the force of the arc pushes the molten
metal through the work piece and severs with APC the material gave an extremely clean
and accurate cuts are possible due to tightly focused heat energy that has a very little
warping, even when cutting thin gauge sheet metal thickness.
1.3
Problem Statements
Conventional materials exhibit in a very excellent technical properties. But however the
constraints such as a high cost of both raw materials and processing limit their use.
Alternatively the advanced machining such as Air Plasma Cutting is normally used.
Material such as Stainless steel, Soft Steel and Aluminum can be used as the work piece
in this type of cutting.
To form a jet for welding, spraying of molten metal and cutting of hard rock or hard
metal a torch is required in temperatures as high as 30000°C this is achieved by injecting
4
air tangentially into an electric arc formed between electrodes in a chamber and this is
resulting vortex of hot gases emerges at very high speed through a hole in the negative
electrode.
Compare to Oxy-Fuel torch or abrasive saws that are using low or no heat affected zone
air plasma cuts ferrous and non-ferrous metal much faster. A clean cut with little or no
dross means less time and money is required to finish the work piece. Parts are virtually
weld-ready.
By using air plasma less preparation of work is required due it is hot enough to burn
through most surface coatings such as paint and rust and still provides an excellent
cutting results and minimal heat input and distortion of the metal as there is with jigsaws
or cutting shears. Applications such as ventilation ductwork (HVAC), tanks or vessels,
plasma cutting offers considerable advantage since there is no fixturing required are
being used to handle difficult shape.
In order to obtain the best factors combination (Distance of Cut) an experiment and
using full factorial methods of the processing is needed to prove feasibility and
effectiveness.
The two distinct speeds can be characterized for plasma cutting. At feed rate above, the
plasma jet does not cut through metal plate and another one at speeds below, the molten
metal from the kerf sticks to the bottom of the plate, forming the so-called dross and
how to properly select a plasma cutting system. Currents, metal thicknesses and nozzle
orifice diameters can be cut by Plasma with AISI D2.
5
1.4
Objectives
The objectives of this experiment are:
1. Design and fabricate a set of jig to guide the Plasma Air Cutter at the HAZ2
CNC Milling Machine.
2. To study about the influence of Plasma Air Cutting Parameters on Distance
of Cut at Tool steel (AISI D2).
3.
To design a series of experiment using the help of Design of Experiments
(DOE) layout in order to study about Plasma Arc Cutting (PAC).
4. To study about the best combination of solution for maximizing the Distance
Of Cut with full factorial method.
1.5
Scope of project
The scope of this project is to:
a) The design of Jig to guide the plasma cutter will perform using Solidwork 2012
software and no performance analysis will generate.
b) The fabricating of jigs design using CO2 Laser cutter machine for each part and
use TiG welding machine for assembly section.
c) This project focuses on the optimization of cutting parameters of Plasma Air
Cutting (PAC).
d) The material used as workpiece was Tool Steel of specification ASTM A681 D2
UNS T30402
e) Design of Experiments (DOE) layout will be used for testing and analyzing with
Full Factorial Method.
f) The self-fabricate machine Haz2 mini CNC Hybrid Machine will used to
perform the machining operation.
6
CHAPTER 2
LITERATUREREVIEW
2.1
Introduction
This part describes the principle of milling process. Air plasma the parameters by
referring the journal beside, cutting tools and workpiece. This chapter also include
about basic introduction about solid work, laser cutting machine and several part about
the jig design.
2.2
AISI D12 Carbon Steel
American Iron and Steel Institute (AISI) D2 is a high-carbon, high-chromium tool steel
alloyed with molybdenum and vanadium. It characterized by high resistance,
compressive strength, firm hardening properties, high hardening stability, and good
resistance to tempering-back. Refer table 2.1 for the details of the material.
7
Table 2. 1 Element in AISI D 12
Typical analysis
C
Si
Mn
Cr
Mo
V
1.55
0.3
0.4
11.8
0.8
0.8
Standard Specification
AISI D2, W-Nr 1.2379
Delivery condition
Soft annealed to approx. 210 HB
Color code
Yellow/ white
2.2.1
Application of AISI D2
AISI D2 is recommended for tool with high wear resistance and moderate toughness
(shock-resistance) beside than that, it supply different finishes, which include hot-rolled,
pre-machined, and fine machined condition. Refer table 2.2 for the properties of AISI
D2.
Table 2. 2 Properties table of AISI D2
Temperature
20 ˚C
200 ˚C
400 ˚C
7.700
7.650
7.600
-
12.3 x 10
-
-
11.2 x 10
12 x 10
20.0
21.0
23.0
210 000
200 000
180 000
-
-
Density
Kg/m³
Coefficient of thermal expansion
-low temperature tempering
per ˚C from 20 ˚C
- high temperature tempering
per ˚C from 20 ˚C
Thermal Conductivity
W/m ˚C
Modulus of elasticity
Mpa
Specific Heat
J/kg ˚C
460
8
2.3
Milling Machine
Milling Machine is mechanism used to process, to produce the finish product and the
chips from raw material. This Milling machines can be represented in two basic forms
which are vertical and horizontal. Positioning of the cutting tool spindle is the basic
form and meanwhile drill press is where work material static on the table and the cutting
tool is moved vertically to machine the material otherwise milling machine which
includes the movement of the work material against the spinning cutter .The movement
of the cutting tool and work piece are accurately controlled to below than 0.025 mm,
usually by means of precision instrument or analogous technology. Milling machines
can be mechanically automated and may be manually operated, or digitally automated
via computer numerical control (CNC). unnecessary number of processes, some
complex, keyway cutting and such as slot, drilling, planning, rebating, die sinking, and
routing can be performed by the Milling machine. Coolant is frequently pumped to the
cutting site to lubricate and to cool the machining process. Techniques to categorize
milling machines are dependent on which conditions are focuses:
Table 2. 3 CNC machine criteria
Criterion
Control
Control
(specifically
among CNC
machines)
Example classification
scheme
Mechanically ;
Manual;
Digitally automated via
NC/CNC;
automated via cams.
Comments
In the CNC age, a very basic
difference is manual versus CNC.
Among manual machines, a
worthwhile distinction is non-DROequipped versus
DRO-equipped
Number of axes (e.g.,
3-axis, 4-axis, or more);
Within this scheme, also:
Full-auto tool changing
Versus semi-auto or
manual tool changing
Pallet-changing versus nonpallet-changing
9
DEPTH OF CUT ANALYSIS USING PLASMA CUTTER FOR
HYBRID MACHINE INNOVATION
This report submitted in accordance with requirement of the Universiti Teknikal
Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Manufacturing Process) (Hons.)
by
WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
B051010224
881211035151
FACULTY OF MANUFACTURING ENGINEERING
2014
DEPTH OF CUT ANALYSIS USING PLASMA CUTTER
FOR HYBRID MACHINE INNOVATION
WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
B051010224
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2014
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: Depth Of Cut Analysis Using Plasma Cutter For Hybrid Machine
Innovation
SESI PENGAJIAN: 2013/14 Semester 2
Saya WAN MOHD AZAHAR BIN WAN MOHD YUSOFF
mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti
Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis.
2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja dengan izin penulis.
3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan
pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan ( ./')
D
SULIT
(Mengandungi maklumat yang berdarjah keselamatan
atau kepentingan Malaysia sebagaimana yang termaktub
dalam AKTA RAHSIA RASMI 1972)
D
TERHAD
(Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan)
D
Tl OAK TERHAD
Disahkan oleh:
ｾ＠ . Me•L
Cop
Alamat Tetap :
5631-W Jin Kbn Sultan
.Ak. .
Pensyarah Kanan
R asnilt :Kejuruteraan Pembuatal'l
•Jnlversiti Tekn1kal Malaysia Melaka
Hang 1 uah Java
7f. 1 CV' Durian i ·'Jngqal, M
Kampung Dusun Raja
15300 Kata Bharu, Kelantan
Tarikh:
IJ- /
G
( JO I 'I
** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi
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© Universiti Teknikal Malaysia Melaka
DECLARATION
I hereby, declare this report entitled "DEPTH OF CUT ANALYSIS USING
PLASMA CUTTER FOR HYBRID MACHINE INNOVATION" is the results of my
own research except as cited in references
Signature
Author's Name
Date
/2
JUNE 2014
© Universiti Teknikal Malaysia Melaka
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM
as a partial fulfillment of the requirements for the degree of Bachelor of
Manufacturing Engineering (Manufacturing Engineering) (Hons.). The member
of the supervisory is as follow:
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© Universiti Teknikal Malaysia Melaka
ABSTRAK
Pada zaman moden sekarang, terdapat perningkatan penyelidikan dalam pemesinan dan
penerokaan dalam inovasi teknologi. Salah satu kejayaan penyelidikan adalah mesin
hibrid iaitu di mana gabungan dua atau lebih proses dalam sebuah mesin. Peningkatan
persaingan dalam industri untuk mencapai kejituan yang tinggi selain kepercayaan
dalam permesinan, mesin konvensional menjadi nadi dalam pelbagai industri. Proses
konvensional yang selalu diketengahkan adalah Pemotongan Secara Plasma Udara.
Kadar kejituan produk akhir dan kebolehan untuk memotong pelbagai bahan yang keras
dan dapat membentuk rekabentuk yang komplek untuk memenuhi permintaan pasaran.
Berdasarkan kajian terdahulu dalam tesis ini telah menganalisis rangka kerja untuk
memaksimumkan keputusan, kaedah separa two factorial telah digunakan untuk tujuan
tersebut. Siri orthogonal yang sesuai telah diputuskan berdasarkan bilangan parameter
dan terdapat peringkat yang melaksanakan bilangan ujian yang minimum. Bahan kerja
Ameriacan Iron and Steel Institute (AISI) D2 iaitu besi bahan kerja digunakan untuk
tujuan ujikaji. Nilai yang terbaik diputuskan dengan menggunakan plot perkadaran yang
utama dan jadual analisis perbezaan (ANOVA). Persamaan regrasi untuk kedalaman
potongan telah dihasilkan melalui perisian Design Expert 7.0. Ujikaji pengesahan untuk
kedalaman potongan telah dijalankan dan keputusan ujikaji yang diberikan untuk
mengesahkan keberkesanan perdekatan ini dengan kedalaman pemotongan sebanyak
4.625mm dengan ralat yang diterima adalah dibawah 10%. Persamaan antara model
berangka peringkat pertama yang dihasilkan dalam projek dengan keputusan ujikaji ini
untuk Jarak pemotongan menggunakan pemotongan secara Plasma adalah 96.7 % dan
persamaan ini dapat digunapakai dalam menjimatkan kos dan masa proses pemotongan.
i
ABSTRACT
Within modern age, there is huge investigation in machining and exploration in
innovation of technology. On the list of successful project is hybrid machine within the
combination of two or more process in single machine. The increasing of competition in
industry and on order to achieve high precision and reliability, today the nontraditional
machining are become lifeline of almost any industry. The most essential nontraditional
machining approaches are Air Plasma Machining. Its finishing, high precision, the
capability to cut variety hard materials and to create complex design raises the need in
industry. Throughout thesis literature review has been analyzed in framework to
parametric optimization of Air Plasma Cutting Machine. In order to achieve target and
optimum results, two level factorial method utilized. The suitable orthogonal array has
been decided according to number of parameter and there levels to execute minimum
testing. The work pieces of American Iron and Steel Institute (AISI) D2 tool steel
materials were used for experiment purpose. The best possible value has been decided
with by using major influence plot and ANOVA table. The Regression equation for
distance of cut has been developed with the help of Design Expert 7.0 Software.
Verification experiments have done to verify the value predicted throughout software.
The verification for Distance of cut run has been carried and experimental results are
provided to confirm the effectiveness of this approach, the DOC value was 4.625mm.
Error within 10 % was allowed, where the similarity between model and experimental
result is 96.7%, the conclusion that, this model can used for reduce the process time and
cost
ii
DEDICATION
For my beloved mother, lecture, friend and also to everyone who were with me all the
time
iii
ACKNOWLEDGEMENT
Alhamdulillah and grateful to ALLAH S.W.T for giving me the strength, patience and
perseverance in completing the Final Year Project
I would like to express my deep sense of respect and gratitude toward my supervisor Dr
Mohd Hadzley bin Abu Bakar, who not only guided the academic/final year project
work but also stood as a teacher and philosopher in realizing the imagination in practical
way, I want to thank him for introducing me for the field of Optimization and giving the
opportunity to work under him. His optimism has provided an invaluable influence on
my career and outlook for the future. I consider it my good fortune to have got an
opportunity to work with such a wonderful person.
I am especially indebted to my mother for their love, sacrifices and support. They are my
teachers after I came to this world and have set great example for me about how to live,
study and work. Also would like to convey my biggest thanks to all the Faculty of
Manufacturing Engineering, University of Technical Malaysia Melaka staff for their
encouragement to supporting me throughout my project.
I also responsible to all people who have been directly and indirectly involved through
contributing ideas and materials and professional opinion.
iv
TABLE OF CONTENT
Abstrak
i
Abstract
ii
Dedication
iii
Acknowledgement
iv
Table of content
v
List of table
viii
List of figure
ix
CHAPTER 1 : INTRODUCTION
1.1
Introduction
1
1.2
Process Description
2
1.3
Problem Statements
4
1.4
Objectives
6
1.5
Scope of project
6
CHAPTER 2 : LITERATURE REVIEW
2.1
Introduction
7
2.2
AISI D12 Carbon Steel
7
2.2.1
8
2.3
Milling Machine
2.3.1
2.4
2.5
Application of AISI D2
9
Milling Machining Operation
12
2.3.1.1 End Milling
12
Cutting Tools.
13
2.4.1
Carbides (uncoated tool)
13
2.4.2
Coated carbide (coated tool)
14
Milling Parameter
15
v
2.5.1
Cutting Speed
16
2.5.2
Feed Rate
16
2.6
Plasma Cutting
17
2.7
Principle Of Plasma Arc Cutting
18
2.8
Plasma Cutting Capability
22
2.9
System
23
2.10
The Process of Air Plasma Cutter
24
2.11
Air Plasma Cutter Parameter
25
2.11.1 Current Flow Rate
25
2.11.2 Feed Rate
25
2.11.3 Standoff height
26
Plasma Torch
26
2.12.1 Torch Stand Off
27
2.12.2
Torch Designs
28
2.21.3
Torch Consumables
28
2.12.5
Swirl/Ceramic Ring.
29
2.12.6
Tip
30
2.12
2.13
Surface Integrity
30
2.13.1 Surface Topography
32
2.13.1.1 Surface Roughness
2.14
2.15
33
2.13.2 Surface metallurgy
37
Design Of Experiments (DOE)
38
2.14.1
40
2-Level Factorial Design
Laser Machining
40
CHAPTER 3: METHODOLOGY
3.1
Introduction
41
vi
3.2
Define The Objective Of The Experiment
41
3.3
Jig Design
42
3.4
Determine the Input Parameters at Low Level and High Level
44
3.5
Design of Experiment Matrix
44
3.6
Identify the Appropriate Response Variable
45
3.7
Preparation of the Experiment
45
3.7.1
Workpiece Preparation
45
3.7.2
Haz 2 Mini Vertical Machining Centre
46
3.8
Conclusion and Recommendation
47
3.9
Flow Chart of Study
48
CHAPTER 4 : RESULT AND DISCUSSION
4.1
Finish Jig Part
49
4.2
Experiment Layout
53
4.3
The Effect of the parameter on Distance off cut
54
4.3.1
Cutting Current
54
4.3.2
Feed Rate
57
4.3.3
Air Pressure
59
4.4
Analysis Of Variance (ANOVA)
61
4.5
Verification Test
62
4.6
Discussion
64
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1
Conclusion
65
5.2
Recommendation
66
REFERENCE
67
APPENDICES
70
vii
LIST OF TABLE
Table 2. 1 Element in AISI D 12
8
Table 2. 2 Properties table of AISI D2
8
Table 2. 3 CNC machine criteria
9
Table 3. 1 Variable factor level
44
Table 3. 2 Design Matrix generated by Design Expert 7.0 software
44
Table 3. 3 Mechanical Properties of work material
46
Table 3. 4 Chemical composition and hardness of AISI D2
46
Table 4. 1 Value of variable at different level
53
Table 4. 2 Experimental Layout for Distance of cut
54
Table 4. 3 ANOVA table for Distance of Cut
61
viii
LIST OF FIGURE
Figure 1.1 Plasma Jet
3
Figure 1.2 TIG and Plasma Arcs
4
Figure 2.1 CNC Milling Machine.
11
Figure 2.2 End milling
12
Figure 2.3 Usual carbide inserts with several shapes
15
Figure 2.4 The principle of the plasma cutting
19
Figure 2.5 Air Plasma
22
Figure 2.6 Air Plasma Setup
23
Figure 2.7 Air Plasma Cutter System
24
Figure 2.8 Torch Stand Off
27
Figure 2.9 Torch Breakdown
28
Figure 2.10 Electrode
29
Figure 2.11 Swirl Ring
29
Figure 2.12 Tip
30
Figure 2.13 The six clusters of important issues that explain the surface integrity of a
complete material
31
Figure 2.14 3D surface of machined workpice
32
Figure 2.15 Surface texture
33
Figure 2.16 Schematic section through a machined surface
37
Figure 3.1 Part 1
42
Figure 3.2 Part 2
42
Figure 3.3 Part 3
43
Figure 3.4 Part 4
43
Figure 3.5 Complete Assembly Jig
43
ix
Figure 3.6 Flow chart of the workpiece preparation
45
Figure 3.7 HAZ2 hybrid mini Machine Centre
46
Figure 3.8 Experiment Flowchart
47
Figure 4.1 Full assembly Jig
49
Figure 4.2 Part 1
50
Figure 4.3 Part 2
51
Figure 4.4 Part 3
51
Figure 4.5 Plasma Torch clamper
52
Figure 4.6 Complete Assembly jig attach to HAZ2 CNC Mini Milling Machine
52
Figure 4.7 Correlation between cutting speed and energy density
55
Figure 4.8 The relationship between current and DOC
55
Figure 4.9 The effect of parameter current on Distance of cut
56
Figure 4.10 The different between current 30 ampere and 20 ampere
56
Figure 4.11 Molten metal for low and high feed rate
57
Figure 4.12 The effect of feed rate on Distance Of Cut
57
Figure 4.13 Diagram for increasing and decreasing feed rate
58
Figure 4.14 The effect of parameter air pressure on Distance of cut
59
Figure 4.15 Different effect of changing Air pressure on Distance of cut
59
Figure 4.16 3D relationship graph
60
Figure 4.17 The different value between experimental value and theory value.
63
x
CHAPTER 1
INTRODUCTION
1.1
Introduction
Topic of this thesis writing is analysis of the surface integrity by using a plasma cutting
for the hybrid machine technique. The focus of this project is keen to obtain an optimum
condition (setting) and also to obtain maximum Distance Of Cut (DOC).
The result of the electrical arcs when air plasma is heating air to a high temperature to
ionize its atoms (the result is due to an unequal number of electron to protons to an equal
temperature an electrically is charged) and allowing it to conduct electricity. The light
will be produced by a fluorescent lamp when you are reading by lights where you see
plasma in action and containing of low pressure mercury within the shinning tube of the
lamp. A across electrodes with a high voltage that is ionized at the ends of the tube
conducts an electric current which result the plasma to radiate which in turn causes the
phosphor coating on the inner surface of the tube to glow (Miller, 2013) .
Oxy-acetylene cutting repeatedly is the process of selecting fast cutting over steel plate
in many years. The using of the plasma cutting has an attractive much full over, for the
some good reasons to perhaps a most vital for many years. Electrical conductive that is
1
an electrical metal such as stainless steel, aluminum; copper, brass etc will be cut by
plasma cutter.
The cutting that is hotter and tighter than an oxy-acetylene flame is ensured by the
plasma jet which gave kerfs width smaller with a cleaner cut. Compare with oxyacetylene the plasma cutting mainly suitable for cutting a sheet metal and meanwhile a
task the oxy-acetylene cutting torch is not mostly well-suited for since it leaves a lot of
slag on the edges. Moreover the particularly tight focus of the plasma arc tends to reduce
heat distortion in the cut parts.
For reaching high quality, in term of work piece dimensional accuracy, surface finish,
high production rate, less wear on the cutting tools, economy of machining in terms of
cost saving and increase of the product performance with reduced environmental impact
are the challenges that mostly focused with. End milling is the ability to control the
process for a better quality of the final product that is very commonly used and very
high importance for machining process in machining industry.
Hardened steels are substantial in reducing machining costs and lead times compared to
more traditional machine route which benefits in the manufacture of components
(Koshy, 2002). AISI D tool steel group is extensively used in making molds and dies,
but the machine ability of this group is very poor indeed.
1.2
Process Description
Plasma cutting is the process used to cut steel and other metals (or sometimes other
materials) by using a plasma torch. In this process an inert gas (in some units,
compressed air) is blown at high speed out of a nozzle and at the same time an electrical
arc is formed through that gas from the nozzle to the surface that has being cut and
turning some of that gas to plasma. Plasma is used for welding and other applications
2
due to it is sufficient hot to melt the metal that has being cut and also fast to blow molten
away from the cut (Sacks, 2005).
Figure 1.1- Plasma Jet
Space or area surrounding the circumference of the electrode that air plasma has
between the inside circumference of the torch tip or nozzle is the chamber where the air
heated and ionized and heating that cause air greatly expand in volume and pressure.
With a very high speed of temperatures; up to 16,000 degrees C and 6000 m/s air exits
from the constricting orifice of the torch nozzle or tip. The intensity and velocity of the
plasma are determined by a several variables including the type of gas, its pressure &
volume, the flow pattern, the amount of electric current, the size and shape of the
constricting tip or nozzle orifice, and the tip to work distance.
3
Figure 1.2 - TIG and Plasma Arcs
High temperature, constricted, high velocity jet of ionized gas exiting from the
constricting orifice of the torch tip to melt a much localized area and remove the molten
material from the metal being cut by the force of the plasma jet are where the APC
process is used. This process is happened when the force of the arc pushes the molten
metal through the work piece and severs with APC the material gave an extremely clean
and accurate cuts are possible due to tightly focused heat energy that has a very little
warping, even when cutting thin gauge sheet metal thickness.
1.3
Problem Statements
Conventional materials exhibit in a very excellent technical properties. But however the
constraints such as a high cost of both raw materials and processing limit their use.
Alternatively the advanced machining such as Air Plasma Cutting is normally used.
Material such as Stainless steel, Soft Steel and Aluminum can be used as the work piece
in this type of cutting.
To form a jet for welding, spraying of molten metal and cutting of hard rock or hard
metal a torch is required in temperatures as high as 30000°C this is achieved by injecting
4
air tangentially into an electric arc formed between electrodes in a chamber and this is
resulting vortex of hot gases emerges at very high speed through a hole in the negative
electrode.
Compare to Oxy-Fuel torch or abrasive saws that are using low or no heat affected zone
air plasma cuts ferrous and non-ferrous metal much faster. A clean cut with little or no
dross means less time and money is required to finish the work piece. Parts are virtually
weld-ready.
By using air plasma less preparation of work is required due it is hot enough to burn
through most surface coatings such as paint and rust and still provides an excellent
cutting results and minimal heat input and distortion of the metal as there is with jigsaws
or cutting shears. Applications such as ventilation ductwork (HVAC), tanks or vessels,
plasma cutting offers considerable advantage since there is no fixturing required are
being used to handle difficult shape.
In order to obtain the best factors combination (Distance of Cut) an experiment and
using full factorial methods of the processing is needed to prove feasibility and
effectiveness.
The two distinct speeds can be characterized for plasma cutting. At feed rate above, the
plasma jet does not cut through metal plate and another one at speeds below, the molten
metal from the kerf sticks to the bottom of the plate, forming the so-called dross and
how to properly select a plasma cutting system. Currents, metal thicknesses and nozzle
orifice diameters can be cut by Plasma with AISI D2.
5
1.4
Objectives
The objectives of this experiment are:
1. Design and fabricate a set of jig to guide the Plasma Air Cutter at the HAZ2
CNC Milling Machine.
2. To study about the influence of Plasma Air Cutting Parameters on Distance
of Cut at Tool steel (AISI D2).
3.
To design a series of experiment using the help of Design of Experiments
(DOE) layout in order to study about Plasma Arc Cutting (PAC).
4. To study about the best combination of solution for maximizing the Distance
Of Cut with full factorial method.
1.5
Scope of project
The scope of this project is to:
a) The design of Jig to guide the plasma cutter will perform using Solidwork 2012
software and no performance analysis will generate.
b) The fabricating of jigs design using CO2 Laser cutter machine for each part and
use TiG welding machine for assembly section.
c) This project focuses on the optimization of cutting parameters of Plasma Air
Cutting (PAC).
d) The material used as workpiece was Tool Steel of specification ASTM A681 D2
UNS T30402
e) Design of Experiments (DOE) layout will be used for testing and analyzing with
Full Factorial Method.
f) The self-fabricate machine Haz2 mini CNC Hybrid Machine will used to
perform the machining operation.
6
CHAPTER 2
LITERATUREREVIEW
2.1
Introduction
This part describes the principle of milling process. Air plasma the parameters by
referring the journal beside, cutting tools and workpiece. This chapter also include
about basic introduction about solid work, laser cutting machine and several part about
the jig design.
2.2
AISI D12 Carbon Steel
American Iron and Steel Institute (AISI) D2 is a high-carbon, high-chromium tool steel
alloyed with molybdenum and vanadium. It characterized by high resistance,
compressive strength, firm hardening properties, high hardening stability, and good
resistance to tempering-back. Refer table 2.1 for the details of the material.
7
Table 2. 1 Element in AISI D 12
Typical analysis
C
Si
Mn
Cr
Mo
V
1.55
0.3
0.4
11.8
0.8
0.8
Standard Specification
AISI D2, W-Nr 1.2379
Delivery condition
Soft annealed to approx. 210 HB
Color code
Yellow/ white
2.2.1
Application of AISI D2
AISI D2 is recommended for tool with high wear resistance and moderate toughness
(shock-resistance) beside than that, it supply different finishes, which include hot-rolled,
pre-machined, and fine machined condition. Refer table 2.2 for the properties of AISI
D2.
Table 2. 2 Properties table of AISI D2
Temperature
20 ˚C
200 ˚C
400 ˚C
7.700
7.650
7.600
-
12.3 x 10
-
-
11.2 x 10
12 x 10
20.0
21.0
23.0
210 000
200 000
180 000
-
-
Density
Kg/m³
Coefficient of thermal expansion
-low temperature tempering
per ˚C from 20 ˚C
- high temperature tempering
per ˚C from 20 ˚C
Thermal Conductivity
W/m ˚C
Modulus of elasticity
Mpa
Specific Heat
J/kg ˚C
460
8
2.3
Milling Machine
Milling Machine is mechanism used to process, to produce the finish product and the
chips from raw material. This Milling machines can be represented in two basic forms
which are vertical and horizontal. Positioning of the cutting tool spindle is the basic
form and meanwhile drill press is where work material static on the table and the cutting
tool is moved vertically to machine the material otherwise milling machine which
includes the movement of the work material against the spinning cutter .The movement
of the cutting tool and work piece are accurately controlled to below than 0.025 mm,
usually by means of precision instrument or analogous technology. Milling machines
can be mechanically automated and may be manually operated, or digitally automated
via computer numerical control (CNC). unnecessary number of processes, some
complex, keyway cutting and such as slot, drilling, planning, rebating, die sinking, and
routing can be performed by the Milling machine. Coolant is frequently pumped to the
cutting site to lubricate and to cool the machining process. Techniques to categorize
milling machines are dependent on which conditions are focuses:
Table 2. 3 CNC machine criteria
Criterion
Control
Control
(specifically
among CNC
machines)
Example classification
scheme
Mechanically ;
Manual;
Digitally automated via
NC/CNC;
automated via cams.
Comments
In the CNC age, a very basic
difference is manual versus CNC.
Among manual machines, a
worthwhile distinction is non-DROequipped versus
DRO-equipped
Number of axes (e.g.,
3-axis, 4-axis, or more);
Within this scheme, also:
Full-auto tool changing
Versus semi-auto or
manual tool changing
Pallet-changing versus nonpallet-changing
9