EFFECT OF EDM DIE-SINKING PARAMETERS ON THE
MATERIAL CHARACTERISTICS OF ALUMINIUM
ALLOY LM6 USING COOPER TUNGSTEN
NOR HALIDA ILYANI BINTI KAMARUDIN
B050910307
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2013
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UNIVERSITI TEKNIKAL MALAYSIA MELAKA
EFFECT OF EDM DIE-SINKING PARAMETERS ON THE
MATERIAL CHARACTERISTICS OF ALUMINIUM ALLOY LM6
USING COOPER TUNGSTEN
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
NOR HALIDA ILYANI BINTI KAMARUDIN
B 050910307
860605115258
FACULTY OF MANUFACTURING ENGINEERING
2013
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: Effect of EDM Die-Sinking Parameters on the Material Characteristics of Aluminium Alloy LM6 Using Cooper Tungsten
SESI PENGAJIAN: 2012/13 Saya NOR HALIDA ILYANI BINTI KAMARUDIN
mengakumembenarkanLaporan PSM inidisimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengansyarat-syaratkegunaansepertiberikut:
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. **Silatandakan ( )
SULIT
TERHAD
TIDAK TERHAD
(Mengandungimaklumat yang berdarjahkeselamatanataukepentingan Malaysiasebagaimana yang termaktubdalamAKTA RAHSIA RASMI 1972) (Mengandungimaklumat TERHAD yang telahditentukanolehorganisasi/badan di
manapenyelidikandijalankan)
AlamatTetap:
Lot 4708 Taman Bistari,
Depan SMK Pelagat, 22000 Jerteh,
Terengganu
Tarikh: ________________________
Disahkanoleh:
Cop Rasmi:
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** 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.
DECLARATION
I hereby, declared this report entitled “Effect Of EDM Die-Sinking Parameters On
The Material Characteristics of Aluminium Alloy Lm6 Using Cooper Tungsten
” is the results of my own research except as cited in references.
Signature : ………………………………………….
Author’s Name : Nor Halida Ilyani Binti Kamarudin
Date : …………………………………………
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 Process) (Hons.). The member of
the supervisory is as follow:
………………………………
i
ABSTRAK
Electric discharge machine (EDM) adalah proses untuk memotong logam keras dan
membentuk secara mendalam dengan cara hakisan arka dalam semua jenis bahan
konduktif. Ia adalah salah satu daripada proses pemesinan bukan tradisional yang
melibatkan pelepasan percikan fana melalui bendalir disebabkan oleh perbezaan
potensi antara elektrod dan bahan kerja. EDM banyak digunakan di mana bentuk
yang kompleks rumit perlu dimesin dalam bahan-bahan yang sangat keras seperti
keluli alat keras. Projek ini mengkaji ciri-ciri EDM hasil dari electrode wear rate
(EWR), material removal rate (MRR), surface roughness (Ra), dan pemerhatian
kawah pada permukaan bahan kerja. Eksperimen telah dilakukan menggunakan
mesin EDM SODICK AQ35L. Design of experiment(DOE) dengan menggunakan
taguchi method telah digunakan untuk mereka bentuk jadual eksperimen ujian, dan
menganalisis faktor penting yang mempengaruhi ciri-ciri pemesinan untuk proses
EDM. Sebanyak sembilan ujikaji telah dijalankan dengan setiap satu diulang
sebanyak tiga kali. Keputusan yang diperolehi daripada kajian ini menunjukkan
bahawa current, pulse on time dan pulse off time adalah faktor yang paling penting
yang melaksanakan ciri-ciri pemesinan EDM. Parameter optimum bagi eksperimen
ini ialah current dengan tahap 1 diikuti oleh pulse on time tahap 2 dan tahap 3 pulse
off time. Ia akan menyokong dengan peratusan sumbangan menggunakan analisis of
varians (ANOVA) bagi MRR, current 62.57%, pulse on time 36.10% dengan
23.41% pulse off time. Kemudian, untuk EWR, current 57.35% dengan 25.31%
daripada pulse on time dan pulse off time 14.11%. Akhir sekali, bagi Ra peratusan
untuk current adalah 99.85%, pulse on time 17.13% dengan 0.10% pulse off time.
Oleh itu, current adalah faktor penting semasa bahan kerja melebur.
ii
ABSTRACT
Electric discharge machining (EDM) is the process for cutting hard metal and
forming deep area by arc erosion in all kind of electro conductive material. It is one
of the non-traditional machining processes that involved a transient spark discharges
through the fluid due to the potential difference between the electrode and the work
piece. EDM is most used where intricate complex shapes need to be machined in
very hard materials such as hardened tool steel. This paper presents a fundamental
study of characteristics of electrode discharge machine (EDM) that are electrode
wear ratio (EWR), material removal rate (MRR), surface roughness (Ra), and
appearance observation. The experiment was done using SODICK AQ35L EDM
machine. Design of experiment (DOE) using taguchi method was applied to design
the experimental number of trials, and analyze the significant factors that affecting
the machining characteristics for EDM process. Total of nine experiments were
conducted with each repeated three times. The results obtained from this research
shows that current, pulse on time and pulse off time were the most significant factor
effecting the EDM machining characteristics. The optimum parameters for this
experiment which are current with level 1 followed by pulse on time of level 2 and
level 3 pulse off time. It will support with the percentage of contribution using
analysis of variance (ANOVA) of MRR, current 62.57%, pulse on time 36.10% with
23.41% pulse off time. Then, for EWR, current 57.35% with 25.31% of pulse on
time and pulse off time 14.11%. Lastly, for Ra the percentage for current is 99.85%,
pulse on time 17.13% with 0.10% pulse off time. Thus, the flow of current melting
the workpiece that’s why the current was the significant factor.
iii
DEDICATION
Special dedicated to my mother
Shamsiah Binti Yusuf
My beloved father
Kamarudin Bin Mat Saman
My supportive siblings
Mohammad Amirul Asyraf Bin Kamarudin
Nur Alifah Ilyana Binti Kamarudin
Muhamad Aliff Haiqal Bin Kamarudin
For my adored friends
Suraya Laily
(Master’s Student)
And to all my relatives and friends for their supports, courage and prayers.
May Allah bless all of you
iv
ACKNOWLEDGEMENT
Alhamdulillah and thank you to Allah S.W.T. for giving me strength and ability to
accomplish this project research successfully. I would like to take the greatest
opportunity to express my sincere and gratitude to my supervisor, Dr. Mohd Amran
Bin Md. Ali for his encouragement, guidance, ideas which enlighten my curiosity,
suggestion, advice and friendship throughout the year in completing this final year
project. Besides, thanks to all the lecturers and staff of the Faculty of Manufacturing
Engineering.
In this opportunity, I would like to give my sincere gratitude to my beloved parents
and family who always pray and give the encouragement while pursuing my research
and project. Their sacrifices are never being forgotten.
My special thanks to the friend that gives support and always company me in making
and complete this project, I really thankful and appreciate it very much.
v
TABLE OF CONTENT
Abstrak i
Abstract ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables viii
List of Figures x
List Abbreviations, Symbols and Nomenclatures xii
CHAPTER 1: INTRODUCTION 1
1.1 Background of the Project 1
1.2 Problem Statement 3
1.3 Objectives 3
1.4 Scopes 4
1.5 Outline of the Report 4
CHAPTER 2: LITERATURE REVIEW 5
2.1 EDM Machining Operations 5
2.1.1 Types of EDM Machines 7
2.1.2 EDM Die Sinking 9
2.2 EDM Machining Parameters 11
2.3 EDM Characteristics 14
2.3.1 Material Removal Rate (MRR) 14
2.3.2 Electrode Wear (EWR) 15
2.3.3 Surface Roughness (Ra) 16
2.3.4 Texture and Cracking of Craters 18
2.4 Material Workpiece 19
2.5 Types of Electrode 19
2.5.1 Copper 20
2.5.2 Graphite 20
vi
2.5.3 Tungsten Carbide 21
2.5.4 Cooper Tungsten 21
2.5.5 Iron 21
2.6 Design of Experiment (DoE) 22
2.6.1 Taguchi Method 22
2.6.1.1 Signal to Noise (S/N) Ratio 23
2.6.1.2 Response to Signal to Noise (S/N) Ratio 24
2.6.1.3 Analysis of Variance (ANOVA) 24
2.7 Summary 25
CHAPTER 3: METHODOLOGY 26
3.1 Experimental Setup 26
3.1.1 Current Experimental Setup 28
3.2 Specimen Preparation 30
3.3 Electrode Preparation 31
3.4 Experimental Parameters 32
3.5 Design of Experiment (DoE) 34
3.5.1 Taguchi Method Using Minitab English Version Sixteen 37
3.6 Summary 39
CHAPTER 4: RESULT AND DISCUSSION 40
4.1 Experimental Data 40
4.1.1 Selection of Factor Using Taguchi Method Design 40
4.1.2 Selection of Factor Level 41
4.1.3 Selection of Orthogonal Array (OA) 41
4.2 Result of the Experiment 42
4.3 Analysis of the Result 44
4.4 Analysis Result of Surface Roughness (Ra) Response 44
4.4.1 Signal to Noise Ratio Response of Ra 44
4.4.2 Signal to Noise Ratio Plot for Ra 45
4.4.3 Validation for Ra 46
4.5 Analysis of Variance (ANOVA) for Ra 47
4.6 Overall Result of Ra 50
vii
4.7 Analysis Result of Material Removal Rate (MRR) Response 51
4.7.1 Signal to Noise Ratio of MRR 52
4.7.2 Signal to Noise Ratio Plot for MRR 52
4.7.3 Validation for MRR 53
4.8 Analysis of Variance (ANOVA) for MRR 54
4.9 Overall Result of MRR 57
4.10 Analysis Result of Electrode Wear Rate (EWR) Response 58
4.10.1 Signal to Noise Ratio of EWR 58
4.10.2 Signal to Noise Ratio Plot for EWR 59
4.10.3 Validation for EWR 60
4.11 Analysis of Variance (ANOVA) for EWR 60
4.12 Overall Result of EWR 63
4.13 Surface Crater Observation 64
4.13.1 Surface Crater of the Smooth Surface 64
4.13.2 Surface Crater of the Rough Surface 65
CHAPTER 5: CONCLUSION AND FUTURE WORK 66
5.1 Conclusion 66
5.2 Future Work 65
REFERENCES 68
APPENDIXES 71
A Final Year Project Planning 71
B Full Data Obtained From Experiments 74
C Results of Surface Roughness 76
D Workpiece Surface Pictures 87
viii
LIST OF TABLES
2.1 Types of EDM machines 7
3.1 Mechanical, Physical, Electrical and Thermal properties of LM6 30
3.2 Properties of copper electrode 32
3.3 Factors and levels for the experiments based on journal 33
3.4 Factors and levels selected for the experiments 34
4.1 Factors and levels selected for experiments 41
4.2 The orthogonal array for all the combination parameter for the
effective factors
42
4.3 Result of the Experiment 43
4.4 Result of the Surface Roughness 44
4.5 Response Table for Signal to Noise Ratios of Ra 45
4.6 Validation Test of Ra 47
4.7 Mean Versus Current for Ra 47
4.8 Mean Versus Pulse On Time for Ra 48
4.9 Mean Versus Pulse Off Time for Ra 49
4.10 Result of Taguchi Method and ANOVA for Ra 50
4.11 Result of the Material Removal Rate 51
4.12 Response Table for Signal to Noise Ratios of MRR 52
4.13 Validation Test of MRR 53
4.14 Mean Versus Current for MRR 54
4.15 Mean Versus Pulse On Time for MRR 55
4.16 Mean Versus Pulse Off Time for MRR 56
4.17 Result of Taguchi Method and ANOVA for MRR 57
4.18 Result of the Electrode Wear Rate 58
4.19 Response Table for Signal to Noise Ratios of EWR 59
4.20 Validation Test of EWR 60
4.21 Mean Versus Current for EWR 60
ix
4.22 Mean Versus Pulse On Time for EWR 61
4.23 Mean Versus Pulse Off Time for EWR 62
4.24 Result of Taguchi Method and ANOVA for EWR 63
x
LIST OF FIGURES
2.1 Concept of EDM 6
2.2 Sinking Electrical Discharge Machining 10
2.3 Schematic representation of the phases of an electric discharge in
EDM and the definition of duty factor τ
11
2.4 Actual profile of single EDM pulse 13
2.5 Pulse wave form of pulse generator 13
2.6 Coordinate used for surface roughness measurement 17
2.7 Sample of surface texture and craters 18
3.1 Experimental methodology 27
3.2 EDM die sinking Sodick AQ35L Series 28
3.3 Precise Digital Balance 29
3.4 Surface Roughness Equipment 29
3.5 Digital Image Microscope 30
3.6 Aluminum Alloy LM6 Dimension 31
3.7 Electrode Dimension 32
3.8 Design of Experiment process flow 36
3.9 The factor and level design are selected 37
3.10 The Taguchi Method is selected with L9 37
3.11 The table of factor 38
3.12 The orthogonal array in Taguchi Method 38
4.1 Main Effects Plot for Signal to Noise Ratios of Ra 46
4.2 Boxplot Mean Versus Current for Ra 48
4.3 Boxplot Mean Versus Pulse On Time for Ra 49
4.4 Boxplot Mean Versus Pulse Off Tiime for Ra 50
4.5 Main Effects Plot for Signal to Noise Ratios of MRR 53
4.6 Boxplot Mean Versus Current for MRR 55
4.7 Boxplot Mean Versus Pulse On Time for MRR 56
xi
4.8 Boxplot Mean Versus Pulse Off Time for MRR 57
4.9 Main Effects Plot for Signal to Noise Ratios of EWR 59
4.10 Boxplot Mean Versus Current for EWR 61
4.11 Boxplot Mean Versus Pulse On Time for EWR 62
4.12 Boxplot Mean Versus Pulse Off Time for EWR 63
4.13 Sample 3 surface observed VIS Digital Imaging Microscope with
230 times magnification
64
4.14 Sample 8 surface observed by VIS Digital Imaging Microscope
with 230 times magnification
65
xii
LIST OF ABBREVIATIONS, SYMBOLS AND
NOMENCLATURE
A - Ampere
ANOVA - Analysis Of Variance
CNC - Computer Numerical Control
DC - Direct Current
DOE - Design of Experiment
Ea - Electrode Weight after machining
Eb - Electrode Weight before machining
EDE - Electro-Discharge Erosion
EDM - Electrical Discharge Machine
EDG - Electric Discharge Grinding
EWR - Electrode Wear Rate
HAZ - Heat Affected Zone
HB - Higher is better
Ip - Peak Current
LB - Lower is better
MRR - Material Removal Rate
NB - Nominal is best
OA - Orthogonal Array
Ra - Surface Roughness
Rq - Root- Mean Squire Average
xiii
Sil2 - Silicate
S/N - Signal to Noise
TiC - Titanium Carbide
TWR - Tool Wear Rate
V - Voltage
Wa - Material Weight after machining
Wb - Material Weight before machining
îe - Peak Current
n - Number of Reading
td - Time Delay
te - Period of Time
tm - Machining time
to - Interval of Time
toff - Pulse Off Time
ton - Pulse On Time
ue - Low Discharge Voltage
ûi - Open Circuit Voltage
μm - Micrometer
µs - Microsecond
1
This section explains the background of the area of the study, the aims and
objectives of this study, and why this study interesting and relevant to the
engineering field.
1.1 Background of the Project
Electrical discharge machine (EDM) die-sinking is an important non-traditional
manufacturing method which it known as EDM die-sinking is a process of
machining electrically conductive materials by using controlled sparks that happen
between an electrode and a work piece in the existence of a dielectric fluid. These
materials would have been difficult to machine by conventional methods, but EDM
die-sinking has made it relatively simple to machine intricate shapes that would be
impossible to produce with conventional cutting tools. In EDM die-sinking process,
the shapes of mold cavities are directly copied from that of tool electrodes, so time
consuming preparation work must be done on the fabrication of the corresponding
tool electrodes (Iqbal A. and Khan A. A.,2010).
The uses of EDM die-sinking in the production of forming tools are to produce
plastics moldings, die castings, forging dies etc., has been firmly established in
recent years. This machining process is continually finding further applications in the
metal machining industry. Although, the application of EDM die-sinking is limited to
the machining of electrically conductive work piece materials, the process has the
INTRODUCTION
CHAPTER 1
2
capability of cutting these materials regardless of their hardness and toughness (Lee
and Li, 2001).
The case study of this project are to determine the best material removal rate (MRR),
electrode wear rate (EWR), surface roughness (Ra), and texture & cracking of
craters. Using this testing, the best performance of the of machining for EDM die-
sinking can be archived when the the best combination of parameters should be
studied to produce an optimum result.
In this project, the effect of EDM die-sinking parameters such as pulse on time, pulse
off time and current on the surface integrity. The condition by using EWR, MRR,
Ra, and texture & cracking of craters will be evaluated with copper beryllium using
electrolytic copper show that usefulness of EDM die-sinking process.
The advantages of the EDM die-sinking machines are it can use to cut of any
material that is electrically conductive, burr is free when using the EDM die-sinking
process, and complex dies will can be produce by EDM die-sinking machine with
accurately, low costs and faster. It also needed the hardened tool material must be
harder than workpiece material to get the good effect and the very important is very
fine holes can be easily drilled.
3
1.2 Problem Statement
In using electrical discharge machine (EDM) die-sinking can be caused poor
performance if not choose the suitable material of the electrode and it will effected of
the test parameters such as pulse on time (ton), pulse off time (toff), voltage (V) and
peak current (Ip). Meanwhile, it also influences the surface integrity when using
EDM like electrode wear rate (EWR), material removal rate (MRR), surface
roughness (Ra), and texture & cracking of craters when it is apply on the aluminum
alloy LM6 containing silicate and titanium carbide. So that, design of experiment
(DOE) will be performed in order to obtain the optimum parameters. Besides that,
erosion of the workpiece must be maximized and the electrode must be minimized in
order to increase the machining efficiency. Therefore, studying the electrode wear
and related significant factors would be effective to enhance the machining
productivity and process reliability.
1.3 Objectives
The objectives of this project are:
a) To study the effect of machining EDM die-sinking parameters such as pulse
on time, pulse off time, voltage and current on the EDM die-sinking
characteristics of aluminium alloy LM6.
b) To evaluate machining characteristics of aluminum alloy LM6 in surface
roughness (Ra), material removal rate (MRR), electrode wear rate (EWR) and
appearance observation.
c) To optimize the machining characteristics using taguchi method and to
analyze the percentage of contribution using analysis of varice (ANOVA)
4
1.4 Scope of the Project
These projects will analysis about the various type of machining parameter relate to
the machining characteristics while EDM die-sinking process. In this process, the
material that use is silicate and titanium carbide and the electrode is copper. The
scope should be low cost and short time use to finishing the process. To analyze the
result and the data collections, the calculations is very important to calculate the
machining characteristics which are electrode wear rate (EWR) and material removal
rate (MRR). The higher friction coefficients are needed when to get surface
roughness and the presence of crater is observed under digital image microscope.
Nowadays, more knowledge about electrical discharge machine is very important. So
that, hopefully with this project can gain a lot of understanding of EDM die-sinking
and get more experience to handle and use it because EDM die-sinking broad
industrial applications. .
1.5 Outline of the report
This report is divided in five chapters as follows:
a) Chapter 1 – background of the project, problem statements, objectives of the
project and the scopes of the project.
b) Chapter 2 – literature review of EDM, machining parameters and
characteristics
c) Chapter 3 – gives information on electrode and material, testing procedure
that involve in the experiment.
d) Chapter 4 – result and analysis of the experiments.
e) Chapter 5 – summarize the results and discussion as well as conclusion of the
case study.
5
This section basically analysis of patent, journal paper, article and conference
paper to the research purpose. The similarities and differences between what
other people investigated had been taken out as well as the machine design. In
order to establish a new machining method for EDM, the research question and
purpose of each review have been evaluated.
2.1 EDM Machining Operation
Electrical Discharge Machining (EDM) is most widely and successfully applied
process in machining of hard metals or those that would be very difficult to machine
with traditional techniques. The material is removed from the work piece by the
thermal erosion process which is by a series of recurring electrical discharges
between a cutting tool acting as an electrode and a conductive work piece in the
presence of a dielectric fluid. This discharge occurs in a voltage gap between the
electrode and work heat from the discharge vaporizes minute particles of work piece
material, which are then washed from the gap by the continuously flushing dielectric
fluid (Reddy et. al. 2010) as shown in Figure 2.1.
LITERATURE REVIEW
CHAPTER 2
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