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
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
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.
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
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:
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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
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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.
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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)
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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.
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List Abbreviations, Symbols and Nomenclatures xii
CHAPTER 1: INTRODUCTION 1
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
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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
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
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
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4.22 Mean Versus Pulse On Time for EWR 61
4.23 Mean Versus Pulse Off Time for EWR 62
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
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
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
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
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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
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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.
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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.
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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.
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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.
