Study Of Sharp Corner Cutting In Wire EDM.
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Study of Sharp Corner Cutting In
Wire EDM
Thesis submitted in accordance with the requirements of the Universiti Teknikal
Malaysia Melaka for the Bachelor Degree of Manufacturing Engineering in
Manufacturing Process
By
Muhammad Iswan bin Ismail
Faculty of Manufacturing Engineering
April 2008
KUTKM Library (Pind.2/2007)
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS TESIS*
JUDUL: _______________________________________________________________
_______________________________________________________________
_______________________________________________________________
SESI PENGAJIAN : _______________________
Saya________________________________________________________________
(HURUF BESAR)
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah) ini disimpan di
Perpustakaan Kolej Universiti Teknikal Malaysia Melaka(UTeM) dengan syarat-syarat
kegunaan seperti berikut:
1. Tesis adalah hak milik Universiti Teknikal Malaysia Melaka.
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untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran
antara institusi pengajian tinggi.
4. **Sila tandakan (√)
SULIT
TERHAD
(Mengandungi maklumat yang berdarjah keselamatan
atau kepentingan Malaysia yang termaktub di dalam
AKTA RAHSIA RASMI 1972)
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(TANDATANGAN PENULIS)
(TANDATANGAN PENYELIA)
Alamat Tetap:
Cop Rasmi:
Tarikh: _______________________
Tarikh: _______________________
* Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau
disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
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UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Karung Berkunci 1200, Ayer Keroh, 75450 Melaka
Tel : 06-233 2421, Faks : 06 233 2414
Email : fkp@utem.edu.my
FAKULTI KEJURUTERAAN PEMBUATAN
Rujukan Kami (Our Ref) :
Rujukan Tuan (Your Ref):
20 Mei 2008
Pustakawan
Perpustakawan Universiti Teknikal Malaysia Melaka
UTeM, Ayer Keroh
MELAKA.
Saudara,
PENGKELASAN TESIS SEBAGAI SULIT/TERHAD
- TESIS SARJANA MUDA KEJURUTERAAN PEMBUATAN (PROSES PEMBUATAN):
MUHAMMAD ISWAN BIN ISMAIL
TAJUK: STUDY OF SHARP CORNER CUTTING IN WIRE EDM
Sukacita dimaklumkan bahawa tesis yang tersebut di atas bertajuk “Study of
Sharp Corner Cutting In Wire EDM” mohon dikelaskan sebagai terhad untuk
tempoh lima (5) tahun dari tarikh surat ini memandangkan ia mempunyai nilai
dan potensi untuk dikomersialkan di masa hadapan.
Sekian dimaklumkan. Terima kasih.
“BERKHIDMAT UNTUK NEGARA KERANA ALLAH”
Yang benar,
En. Abd. Halim Hakim b. Abd. Aziz
Pensyarah,
Fakulti Kejuruteraan Pembuatan
06-2332680
DECLARATION
I hereby, declared this thesis entitled “Study of Sharp Corner Cutting In Wire EDM” is
the result of my own research except as cited in references.
Signature
:
………………………………………………………….
Author’ s Name
:
………………………………………………………….
Date
:
………………………………………………………….
ABSTRACT
EDM or Electrical Discharge Machining is a process by which metal is removed by
electrical energy. A spark is discharged from an electrode vaporizing the metal. In really
EDM is a very precise method of machining and is used when a metal is too hard or
tough to machine conventionally. The experimental study presented in this paper aims to
select the most suitable cutting and offset parameter combination for the wire electrical
discharge machining process in order to get the desired surface roughness value,
dimensional and corner cutting accuracy for the machined workpieces. A series of
experiments have been performed on two types of steel material with same thicknesses.
The test specimens have been cut by using different cutting and offset parameter
combinations of the “Mitsubishi RA90” wire electrical discharge machine in the
University Technical Malaysia Melaka CNC center lab. The surface roughness of the test
pieces has been measured by using a surface roughness measuring device. The dimension
accuracy will be measured by optical comparator and digital caliper. For accuracy of
sharp corner cutting image analyzer will be used. The related tables and charts have been
prepared for material type, wire diameter and wire type. The tables and charts can be
practically used for EDM parameter selection for the desired workpiece.
i (a)
ABSTRACT
EDM atau Mesin Discas Electrik adalah satu proses di mana pemotongan logam oleh
tenaga elektrik. Satu percikan api dihasilkan daripada satu elektrod menjadi wap logam.
Dengan maksud lain EDM adalah satu kaedah pemesinan yang sangat tepat dan sesuai
digunakan bagi logam-logam yang sangat keras atau sukar untuk pemesinanan secara
konvensional. Kajian yang disampaikan di dalam laporan ini bermatlamat memilih
pemotongan yang paling sesuai dan gabungan parameter bagi mengimbangi proses
nyahcas elektrik untuk mendapatkan permukaan pemotonagan yang licin, dimensi dan
ketepatan darjah untuk sudut yang tajam bagi sesuatu hasil kerja. Satu siri ujian telah
dilakukan ke atas dua jenis bahan keluli dengan ketebalan yang sama. Spesimenspesimen ujian telah dipotong dengan menggunakan gabungan-gabungan parameter yang
berbeza bagi memotong dan mengimbangi nyahcas elektrik
dari mesin “Mitsubishi
RA90” di dalam makmal CNC, Universiti Teknikal Malaysia Melaka. Profile permukaan
kepingan-kepingan telah diukur dengan menggunakan satu penyukat profile permukaan
bahan. Ketepatan dimensi pula akan diukur oleh pembanding optik dan angkup venier.
Untuk ketepatan pemotongan sudut tajam, mikroskop penganalisis akan digunakan.
Jadual-jadual berhubungan dan carta-carta yang akan disediakan bagi jenis bahan, jejari
elektrod dan jenis elektrod. Jadual-jadual dan carta-carta yang dihasilkan boleh dijadikan
panduan bagi pemilihan parameter untuk pemesinan EDM.
i (b)
DEDICATION
Specially dedicated to my beloved father, Ismail bin Osman and my mother, Wan Hasnah
binti Wan Ali and who are very concerns, understanding patient and supporting, thank
you for everything to my supervisors, En. Abd. Halim Hakim b. Abd. Aziz, my sisters,
brother and all my friends. The work and success will never be achieved without all of
you.
ii
ACKNOWLEDGEMENT
ALHAMDULLILAH, with the guidance and support I received, my final year thesis project is
now completed. I would like to express my special greatest gratitude to my supervisor, En. Halim
Hakim Abd Aziz for his valuable guidance and continuing support throughout the entire course of
my work. Truly without his guides and wisdom I would have been lost. To PSM panels Mr.
Sivarao a/l Subramonian and Dr. Ir. Thoguluva Raghavan Vijayaram, your advice and help make
my PSM more perfect and achive the objective. I also want express my sincere and deepest
gratitude to my family Aboh, Ma, Kaklong, Kokja, Udin, Anas and Amir that give me fully
support and always prays for my success.
Not to forget, my special appreciation is addressed to En. Fendi and the other FKP technician for
their technical assistance and supervision on the EDM wire cutting machine and equipment. My
deepest gratitude also goes to all the lectures in FKP for their guidance and support. Also to my
friends that support and help me from behind, thanks to all of you. Finally, last but not least, I
would like to thank any person or any side that I can’t remember that help me to finish my PSM.
All the help that you all give to me I will not forget forever.
iii
TABLE OF CONTENTS
Abstract
i
Dedication
ii
Acknowledgement
iii
Table of Contents
iv
List of Figures
ix
List of Tables
xiv
List of Abbreviations, Symbols, Specialized Nomenclature
xv
1. 0 INTRODUCTION
1
1.1 Background
1
1.2 Problem Statements
2
1.3 Objectives of the Study
2
1.4 Scopes of the Limitation
2
1.5 Important of Study
3
1.6 Outline of Study
3
2. 0 LITERATURE REVIEWS
4
2.1 Introduction
4
2.1.1 Electro Mechanical Theory
4
2.1.2 Thermo Mechanical Theory
4
2.1.3 Thermo Electric Theory
5
2.2 Introduction of EDM
5
2.3 General History of EDM
6
iv
2.4 Working Principle of EDM
7
2.4.1 Mechanical Structure
13
2.4.2 Spark Generator
13
2.4.3 Servo system
14
2.4.4 Dielectric circuit
14
2.5 Types of EDM
15
2.5.1 Die-Sinking EDM
15
2.5.2 Wire Cut EDM
20
2.5.3 Electrical discharge grinding (EDG)
17
2.5.4 Electrical discharge machining small hole
17
2.6 Wire electrical discharge machining (WEDM)
19
2.6.1 Introduction of WEDM wire cut
19
2.6.2 History of WEDM
20
2.6.3 Wire-cut Machine
21
2.6.4 Wire Cut EDM Electrodes
23
2.6.4.1 Copper Wire
25
2.6.4.2 Brass Wire
25
2.6.4.3 Zinc-Coated Wire
26
2.7 Process Factors of EDM
29
2.7.1 Electrode Material
29
2.7.2 Dielectric Fluid
30
2.8 ON time, OFF time and Ip
31
2.9 Power Source
31
2.10 Measurement Method
33
2.10.1 Material Removal Rate (MRR)
33
2.10.2 Dimensional Accuracy
34
2.10.3 Surface Finish Texture
34
2.10.3.1 Surface Roughness Measurement and Specification
2.10.4 Corner Radius
35
40
2.10.4.1 Introduction to Sharp Corner
40
2.10.4.2 Causes of Inaccuracies at Sharp Corner
41
v
2.11 Wear Electrode
44
2.12 Workpiece Material
45
2.12.1 Mild Steel (Low carbon steel)
45
2.12.2 Aluminum
46
3.0 METHODOLOGY RESEARCH
47
3.1 Process Planning
47
3.2 Equipment
48
3.2.1 Wire Cut EDM (Model Mitsubishi RA 90)
3.3 Analysis Equipment
48
50
3.3.1 Digital Calliper
50
3.3.2 Optical Comparator
50
3.3.3 Surface Finish Analysis
52
3.3.4 Metallurgy Microscope (Image Analyzer)
53
3.4 Methodology Planning
55
3.5 Experiment Methodology
56
3.6 Gantt Chart
62
3.6.1 Task A
62
3.6.2 Task B
62
3.6.3 Task C
62
3.6.4 Task D
63
3.6.5 Task E
63
3.6.6 Task F
63
3.6.7 Task G
63
3.6.8 Task H
63
3.6.9 Task I
64
3.6.10 Task J
64
3.6.11 Task K
64
3.6.12 Task L
64
vi
4.0 RESULT
65
4.1 Setting Condition of E 932
65
4.2 Influence of Wire Tension
65
4.2.1 For Mild Steel
65
4.2.2 For Aluminum
67
4.3 Influence of Wire Speed
68
4.3.1 For Mild Steel
68
4.3.2 For Aluminum
69
4.4 Results for Corner Radius
71
4.4.1 For Mild Steel
71
4.4.2 For Aluminum
74
5.0 DATA ANALSIS AND DISCUSSION
76
5.1 Influence of Wire Tension
5.1.1 For Mild Steel
76
77
5.1.2 For Aluminum
83
5.1.3 Influents of Wire Tension
89
5.1.3.1 Dimensional Accuracy
89
5.1.3.2 Effect of Wire Tension to Surface Roughness
90
5.2 Influence of Wire Speed
5.2.1 For Mild Steel
93
5.2.2 For Aluminum
99
5.2.3 Influence of Wire Speed
105
5.2.3.1 Dimensional Accuracy
105
5.2.3.2 Surface Roughness
106
5.2.3.3 Effect of Wire Speed to Corner Radius
106
5.3 Influence of Current Peak (Ip)
107
5.3.1
For Mild Steel (With Wire Tension, WT)
108
5.3.2
For Aluminum (With Wire Tension, WT)
110
5.3.3
Mild Steel (With Wire Speed)
116
5.3.3.1 Dimensional Accuracy
116
5.3.3.2 Surface Roughness
117
5.3.3.3 Corner Radius
118
vii
5.4 Influence of Material
5.4.1
119
EDM Wire-Cut Machining Base on Material
123
5.4.1.1
For Mild Steel
123
5.4.1.2
For Aluminum
124
6.0 CONCLUSION AND RECOMMENDATION
6.1 Recommendation
125
130
7.0 REFERENCE
131
8.0 APPENDIX
133
viii
LIST OF FIGURES
2.1
Electric discharge machining sparking gap
7
2.2
Basic components of EDM
8
2.3
Sparking occurs at closest points between the electrode and
9
workpiece
2.4
Next spark occurs of closest points between electrode one
9
workpiece8g
2.5
Spark occurs within a column of ionized dielectric fluid
10
2.6
Spark ON: electrode and workpiece material vaporized
11
2.7
Spark OFF: vaporized cloud suspended in dielectric fluid
11
2.8
Spark-OFF: vaporized cloud solidifies to form EDM chip
12
2.9
Basic Elements of an EDM system
13
2.10
Die Sinking or penetration
15
2.11
Wire electrical discharge machining (WEDM)
16
2.12
Electrical discharge grinding (EDG)
17
2.13
Small Hole EDM Drilling
18
2.14
Wire electrical discharge machining (WEDM) Products
19
2.15
Basic wire-cut EDM machine
21
2.16
Basic features of wire-EDM
22
2.17
Wire-cut electrode wear
24
2.18
Brass electrode wire for EDM wire cut machine
25
2.19
Double-boiler principle
27
2.20
Vaporized zinc reduces electrode temperature
27
2.21
Surface characteristics
35
2.22
Surface Roughness Measuremnt
35
2.23
The Arithmetic Mean Value, Ra
36
2.24
Shows the error of corner is defined and presented
40
2.25
Show schematic representation of the wire-EDM during cutting.
42
Illustrates the wire deformation during a rough cut
3.1
Inside the EDM wire cut machine
49
ix
3.2
Wire Cut EDM (Model Mitsubishi RA 90)
49
3.3
Digital Calliper
50
3.4
Optical Comperator
51
3.5
Surface roughness tester (Model Mitutoyo SJ 301)
52
3.6
Metallurgy Microscope (Image Analyzer)
54
3.7
Axio imager accept a wide range of high contrast objectives
54
3.8
Methodology Planning Flow Chart
55
3.9
Lab or Work Machining Flow Chart
56
3.10
The suitable jig is very important for the machining
57
3.11
CAD/W software
58
3.12
The dimension of the sample
58
3.13
Shows the cutting path of the materials
61
4.1
Corner radius for peak current 8 and wire speed 2
71
4.2
Corner radius for peak current 8 and wire speed 4
72
4.3
Corner radius for peak current 4 and wire tension 4
72
4.4
Corner radius for peak current 6 and wire tension 8
73
4.5
Corner radius for peak current 4 and wire tension 4
74
4.6
Corner radius for peak current 8 and wire tension 8
74
4.7
Corner radius for peak current 6 and wire tension 4
75
4.8
Corner radius for peak current 8 and wire tension 2
75
5.1(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 4 (Mild Steel)
77
5.1(b)
Graph Surface Roughness vs Wire Tension for Ip 4 (Mild Steel)
77
5.1(c)
Graph Corner Radius vs Wire Tension for Ip 4 (Mild Steel)
78
5.2(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 6 (Mild Steel)
78
5.2(b)
Graph Surface Roughness vs Wire Tension for Ip 6 (Mild Steel)
79
5.2(c)
Graph Corner Radius vs Wire Tension for Ip 6 (Mild Steel)
79
5.3(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 8 (Mild Steel)
80
5.3(b)
Graph Surface Roughness vs Wire Tension for Ip 8 (Mild Steel)
80
5.3(c)
Graph Corner Radius vs Wire Tension for Ip 8 (Mild Steel)
81
5.4(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 12(Mild
81
Steel)
5.4(b)
Graph Surface Roughness vs Wire Tension for Ip 12 (Mild Steel)
82
5.4(c)
Graph Corner Radius vs Wire Tension for Ip 12 (Mild Steel)
82
x
5.5(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 4
83
(Aluminum)
5.5(b)
Graph Surface Roughness vs Wire Tension for Ip 4
83
(Aluminum)
5.5(c)
Graph Corner Radius vs Wire Tension for Ip 4 (Aluminum)
84
5.6(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 6
84
(Aluminum)
5.6(b)
Graph Surface Roughness vs Wire Tension for Ip 6 (Aluminum)
85
5.6(c)
Graph Corner Radius vs Wire Tension for Ip 6 (Aluminum)
85
5.7(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 8
86
(Aluminum)
5.7(b)
Graph Surface Roughness vs Wire Tension for Ip 8 (Aluminum)
86
5.7(c)
Graph Corner Radius vs Wire Tension for Ip 8 (Aluminum)
87
5.8(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 12
87
(Aluminum)
5.8(b)
Graph Surface Roughness vs Wire Tension for Ip 12 (Aluminum)
88
5.8(c)
Graph Corner Radius vs Wire Tension for Ip 12 (Aluminum)
88
5.9(a)
Graph Dimensional Accuracy vs Wire Speed for Ip 4 (Mild Steel)
93
5.9(b)
Graph Surface Roughness vs Wire Speed for Ip 4 (Mild Steel)
93
5.9(c)
Graph Corner Radius vs Wire Speed for Ip 4 (Mild Steel)
94
5.10(a) Graph Dimensional Accuracy vs Wire Speed for Ip 6 (Mild Steel)
94
5.10(b) Graph Surface Roughness vs Wire Speed for Ip 6 (Mild Steel)
95
5.10(c) Graph Corner Radius vs Wire Speed for Ip 6 (Mild Steel)
95
5.11(a) Graph Dimensional Accuracy vs Wire Speed for Ip 8 (Mild Steel)
96
5.11(b) Graph Surface Roughness vs Wire Speed for Ip 8 (Mild Steel)
96
5.11(c) Graph Corner Radius vs Wire Speed for Ip 8 (Mild Steel)
97
5.12(a) Graph Dimensional Accuracy vs Wire Speed for Ip 12 (Mild Steel)
97
5.12(b) Graph Surface Roughness vs Wire Speed for Ip 12 (Mild Steel)
98
5.12(c) Graph Corner Radius vs Wire Speed for Ip 12 (Mild Steel)
98
5.13(a) Graph Dimensional Accuracy vs Wire Speed for Ip 4 (Aluminum)
99
5.13(b) Graph Surface Roughness vs Wire Speed for Ip 4 (Aluminum)
99
xi
5.13(c) Graph Corner Radius vs Wire Speed for Ip 4 (Aluminum)
100
5.14(a) Graph Dimensional Accuracy vs Wire Speed for Ip 6 (Aluminum)
100
5.14(b) Graph Surface Roughness vs Wire Speed for Ip 6 (Aluminum)
101
5.14(c) Graph Corner Radius vs Wire Speed for Ip 6 (Aluminum)
101
5.15(a) Graph Dimensional Accuracy vs Wire Speed for Ip 8 (Aluminum)
102
5.15(b) Graph Surface Roughness vs Wire Speed for Ip 8 (Aluminum)
102
5.15(c) Graph Corner Radius vs Wire Speed for Ip 8 (Aluminum)
103
5.16(a) Graph Dimensional Accuracy vs Wire Speed for Ip 12(Aluminum)
103
5.16(b) Graph Surface Roughness vs Wire Speed for Ip 12 (Aluminum)
104
5.16(c) Graph Corner Radius vs Wire Speed for Ip 12 (Aluminum)
104
5.17(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WT)
108
5.17(b) Graph Surface Roughness vs Peak Current, Ip (With WT)
108
5.17(c) Graph Corner Radius vs Peak Current, Ip (With WT)
109
5.18(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WT)
109
5.18(b) Graph Surface Roughness vs Peak Current, Ip (With WT)
110
5.18(c) Graph Corner Radius vs Peak Current, Ip (With WT)
110
5.19(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WS)
111
5.19(b) Graph Surface Roughness vs Peak Current, Ip (With WS)
111
5.19(c) Graph Corner Radius vs Peak Current, Ip (With WS)
112
5.20(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WS)
112
5.20(b) Graph Surface Roughness vs Peak Current, Ip (With WS)
113
5.20(c) Graph Corner Radius vs Peak Current, Ip (With WS)
113
5.21(a) Graph Dimensional Accuracy vs Wire Tension (Base on Material)
120
5.21(b) Graph Surface Roughness vs Wire Tension (Base on Material)
120
5.21(c) Graph Corner Radius vs Wire Tension (Base on Material)
121
5.22(a) Graph Dimensional Accuracy vs Wire Speed (Base on Material)
121
5.22(b) Graph Surface Roughness vs Wire Speed (Base on Material)
122
5.22(c) Graph Corner Radius vs Wire Speed (Base on Material)
122
8.1
Clamping the workpiece
133
8.2
Optical Comparator Value panel
133
8.3
Surface roughness tester
133
8.4
Edm Control Panel Screen
133
xii
8.5
EDM Control Panel
134
8.6
Optical Comparator Image
134
xiii
LIST OF TABLES
2.1
Show appropriate wire type for different application
28
2.2
Advantage and disadvantage type of power source
32
2.3
ISO standard Ra value for common manufacturing method
38
3.1
Table for constant EDM wire cut parameters
60
3.2
Table of function and setting range for EDM wire cut constant parameter
60
3.3
Gantt Chart of the Project
65
4.1
Machining Constants Parameters
65
8.1
Table of Parameters for Mitsubishi WEDM RA Series
xiv
135
LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED
NOMENCLATURE
PS
Function to set the power supply mode
V0
Main power supply voltage
OFF
Pulse OFF time
SA
Stabilizer A; to make machining speed will be faster
SB
Stabilizer B; high value, the slower the machining will be
SC
Stabilizer C; machining for finishing circuit
SE
Stabilizer E; used particularly for 1st cut machining
VG
Voltage Gap; to set average machining voltage used
Ip
Peak Current
WS
Wire Speed
WT
Wire tension
xv
CHAPTER 1
INTRODUCTION
1.1
Background
Machining is an importance process in manufacturing engineering. It is dividing by two
methods to say conventional machining and unconventional machining. For example of
the conventional machining are milling, drilling and lathe. According this method, the
quality of production are depend of efficiency operator, type of process is choosing and
type of material is used. Also get in certain case where the conventional machining is not
suitable to applicable. Such as an example where the shape we want to produced are
complicated. It is because to producing the complicated partial are need high cost and a
long of producing time. Furthermore in a modern technology, get a various new material
from other sources. It is shown indeed we need a new method for improvement and
upgrading the quality of metal machining. So that, to solve this problem we need
unconventional machining for exceed the weakness by unconventional machining is
better if the parameter choosing is better. It is because this method is limited for certain
parameter only. Electrical discharge machining EDM is one of the most accurate
manufacturing methods of working exceptionally hard metals and other materials that are
difficult to machine cleanly with more conventional methods. EDM is a process of
elimination that erodes or removes metal and material in the path of electrical discharges
that form an arc between an electrode tool and the workpiece until the desired part is
attained. Using this process is extremely accurate, reliable and affordable, so it is
becoming an increasingly popular choice for many companies. But refers to the demand
of the industries that need very accuracy products so the EDM process must be have an
improvement process and research time to time so it can fulfill the demand of the
industries.
1
1.2
Problem Statement
In machining process, it is very important to get optimum cutting result where it can
reduce cutting time, reduce the wear of electrode, save the operation cost, save the
material cost, perfect sharp corner cutting with high accuracy dimensional and finishing
with a good surface texture. But then, the problem will be occurs is finishing surface
texture are not good and unsatisfactory. Also for sharp corner cutting the have many
errors will occurs. In industry actually sharp corner must be avoided because of it
difficult to produce with high accuracy but the problem will occurs when the product
need the sharp corner machining. The problem also included how to find the best
machining parameter for sharp corner cutting that will be reach to the best result of sharp
corner cutting.
1.3
Objective of Study
The purposes of this study are:
(a) To study the cutting process of sharp corner
(b) To study the relationship of sharp corner angle, surface roughness and
dimensional accuracy and workpiece material.
(c) To propose the optimum condition for machining sharp corner.
1.4
Scope and Limitation
For this study, EDM wire cut (Model Mitsubishi RA 90) will be used in CNC laboratory in
UTeM. The result of this study just suitable for this EDM wire cut (Model Mitsubishi RA 90) and
not applicable to other types of EDM wire cut or other project. Overall the project is taken as long as
5 month which is started on December 2007 until April 2008. The early choice of wire electrode is
brass wire with diameter 0.25mm. The material that will be used is mild steel and aluminum with the
thickness is 10mm.
2
1.5
Important of Study
The important of this study is as follows:
(a) To fine the best method and parameters to produce the high accuracy of sharp
corner cutting using EDM wire cut machine (Model Mitsubishi RA 90).
(b) To fine the improvement method for produce good surface finish and high accuracy of
dimensional using EDM wire cut machine (Model Mitsubishi RA 90).
(c) Can reduce the damage of the material and the machine when the machining
process.
(d) Will be a reference for academic studies which is related to EDM wire cut
machining (Model Mitsubishi RA 90).
1.6
Outline of Study
Overall this report is divided into 5 chapters. For Chapter 1 is mainly describe about the
introduction which is highlight to background, problem statement, objective of study,
scope and limitation, important of study and study outline. Chapter 2 is the literature
review which in this chapter will discuss the definition and the introduction of EDM wire cut
generally includes the operation of the machine. This chapter also will discuss the characteristic
and the basic concept of EDM machining. Then, Chapter 3 is describing about methodology of
this study. This chapter will discuss the process planning, parameter of machining and types of
material. This chapter also will describe about the specification of EDM wire cut (Model
Mitsubishi RA 90) that will be uses for the study and the measurement apparatus. For Chapter 4
is result and discussion of the study observation. This chapter will compile all the result and the
result will be form into graphs to be analyzed. The result will be discussed also in this chapter.
Chapter 6 will shown the conclusion and the recommendation of the whole this project that has
been done.
3
Study of Sharp Corner Cutting In
Wire EDM
Thesis submitted in accordance with the requirements of the Universiti Teknikal
Malaysia Melaka for the Bachelor Degree of Manufacturing Engineering in
Manufacturing Process
By
Muhammad Iswan bin Ismail
Faculty of Manufacturing Engineering
April 2008
KUTKM Library (Pind.2/2007)
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS TESIS*
JUDUL: _______________________________________________________________
_______________________________________________________________
_______________________________________________________________
SESI PENGAJIAN : _______________________
Saya________________________________________________________________
(HURUF BESAR)
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah) ini disimpan di
Perpustakaan Kolej Universiti Teknikal Malaysia Melaka(UTeM) dengan syarat-syarat
kegunaan seperti berikut:
1. Tesis adalah hak milik Universiti Teknikal Malaysia Melaka.
2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran
antara institusi pengajian tinggi.
4. **Sila tandakan (√)
SULIT
TERHAD
(Mengandungi maklumat yang berdarjah keselamatan
atau kepentingan Malaysia yang termaktub di dalam
AKTA RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
(TANDATANGAN PENULIS)
(TANDATANGAN PENYELIA)
Alamat Tetap:
Cop Rasmi:
Tarikh: _______________________
Tarikh: _______________________
* Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau
disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Karung Berkunci 1200, Ayer Keroh, 75450 Melaka
Tel : 06-233 2421, Faks : 06 233 2414
Email : fkp@utem.edu.my
FAKULTI KEJURUTERAAN PEMBUATAN
Rujukan Kami (Our Ref) :
Rujukan Tuan (Your Ref):
20 Mei 2008
Pustakawan
Perpustakawan Universiti Teknikal Malaysia Melaka
UTeM, Ayer Keroh
MELAKA.
Saudara,
PENGKELASAN TESIS SEBAGAI SULIT/TERHAD
- TESIS SARJANA MUDA KEJURUTERAAN PEMBUATAN (PROSES PEMBUATAN):
MUHAMMAD ISWAN BIN ISMAIL
TAJUK: STUDY OF SHARP CORNER CUTTING IN WIRE EDM
Sukacita dimaklumkan bahawa tesis yang tersebut di atas bertajuk “Study of
Sharp Corner Cutting In Wire EDM” mohon dikelaskan sebagai terhad untuk
tempoh lima (5) tahun dari tarikh surat ini memandangkan ia mempunyai nilai
dan potensi untuk dikomersialkan di masa hadapan.
Sekian dimaklumkan. Terima kasih.
“BERKHIDMAT UNTUK NEGARA KERANA ALLAH”
Yang benar,
En. Abd. Halim Hakim b. Abd. Aziz
Pensyarah,
Fakulti Kejuruteraan Pembuatan
06-2332680
DECLARATION
I hereby, declared this thesis entitled “Study of Sharp Corner Cutting In Wire EDM” is
the result of my own research except as cited in references.
Signature
:
………………………………………………………….
Author’ s Name
:
………………………………………………………….
Date
:
………………………………………………………….
ABSTRACT
EDM or Electrical Discharge Machining is a process by which metal is removed by
electrical energy. A spark is discharged from an electrode vaporizing the metal. In really
EDM is a very precise method of machining and is used when a metal is too hard or
tough to machine conventionally. The experimental study presented in this paper aims to
select the most suitable cutting and offset parameter combination for the wire electrical
discharge machining process in order to get the desired surface roughness value,
dimensional and corner cutting accuracy for the machined workpieces. A series of
experiments have been performed on two types of steel material with same thicknesses.
The test specimens have been cut by using different cutting and offset parameter
combinations of the “Mitsubishi RA90” wire electrical discharge machine in the
University Technical Malaysia Melaka CNC center lab. The surface roughness of the test
pieces has been measured by using a surface roughness measuring device. The dimension
accuracy will be measured by optical comparator and digital caliper. For accuracy of
sharp corner cutting image analyzer will be used. The related tables and charts have been
prepared for material type, wire diameter and wire type. The tables and charts can be
practically used for EDM parameter selection for the desired workpiece.
i (a)
ABSTRACT
EDM atau Mesin Discas Electrik adalah satu proses di mana pemotongan logam oleh
tenaga elektrik. Satu percikan api dihasilkan daripada satu elektrod menjadi wap logam.
Dengan maksud lain EDM adalah satu kaedah pemesinan yang sangat tepat dan sesuai
digunakan bagi logam-logam yang sangat keras atau sukar untuk pemesinanan secara
konvensional. Kajian yang disampaikan di dalam laporan ini bermatlamat memilih
pemotongan yang paling sesuai dan gabungan parameter bagi mengimbangi proses
nyahcas elektrik untuk mendapatkan permukaan pemotonagan yang licin, dimensi dan
ketepatan darjah untuk sudut yang tajam bagi sesuatu hasil kerja. Satu siri ujian telah
dilakukan ke atas dua jenis bahan keluli dengan ketebalan yang sama. Spesimenspesimen ujian telah dipotong dengan menggunakan gabungan-gabungan parameter yang
berbeza bagi memotong dan mengimbangi nyahcas elektrik
dari mesin “Mitsubishi
RA90” di dalam makmal CNC, Universiti Teknikal Malaysia Melaka. Profile permukaan
kepingan-kepingan telah diukur dengan menggunakan satu penyukat profile permukaan
bahan. Ketepatan dimensi pula akan diukur oleh pembanding optik dan angkup venier.
Untuk ketepatan pemotongan sudut tajam, mikroskop penganalisis akan digunakan.
Jadual-jadual berhubungan dan carta-carta yang akan disediakan bagi jenis bahan, jejari
elektrod dan jenis elektrod. Jadual-jadual dan carta-carta yang dihasilkan boleh dijadikan
panduan bagi pemilihan parameter untuk pemesinan EDM.
i (b)
DEDICATION
Specially dedicated to my beloved father, Ismail bin Osman and my mother, Wan Hasnah
binti Wan Ali and who are very concerns, understanding patient and supporting, thank
you for everything to my supervisors, En. Abd. Halim Hakim b. Abd. Aziz, my sisters,
brother and all my friends. The work and success will never be achieved without all of
you.
ii
ACKNOWLEDGEMENT
ALHAMDULLILAH, with the guidance and support I received, my final year thesis project is
now completed. I would like to express my special greatest gratitude to my supervisor, En. Halim
Hakim Abd Aziz for his valuable guidance and continuing support throughout the entire course of
my work. Truly without his guides and wisdom I would have been lost. To PSM panels Mr.
Sivarao a/l Subramonian and Dr. Ir. Thoguluva Raghavan Vijayaram, your advice and help make
my PSM more perfect and achive the objective. I also want express my sincere and deepest
gratitude to my family Aboh, Ma, Kaklong, Kokja, Udin, Anas and Amir that give me fully
support and always prays for my success.
Not to forget, my special appreciation is addressed to En. Fendi and the other FKP technician for
their technical assistance and supervision on the EDM wire cutting machine and equipment. My
deepest gratitude also goes to all the lectures in FKP for their guidance and support. Also to my
friends that support and help me from behind, thanks to all of you. Finally, last but not least, I
would like to thank any person or any side that I can’t remember that help me to finish my PSM.
All the help that you all give to me I will not forget forever.
iii
TABLE OF CONTENTS
Abstract
i
Dedication
ii
Acknowledgement
iii
Table of Contents
iv
List of Figures
ix
List of Tables
xiv
List of Abbreviations, Symbols, Specialized Nomenclature
xv
1. 0 INTRODUCTION
1
1.1 Background
1
1.2 Problem Statements
2
1.3 Objectives of the Study
2
1.4 Scopes of the Limitation
2
1.5 Important of Study
3
1.6 Outline of Study
3
2. 0 LITERATURE REVIEWS
4
2.1 Introduction
4
2.1.1 Electro Mechanical Theory
4
2.1.2 Thermo Mechanical Theory
4
2.1.3 Thermo Electric Theory
5
2.2 Introduction of EDM
5
2.3 General History of EDM
6
iv
2.4 Working Principle of EDM
7
2.4.1 Mechanical Structure
13
2.4.2 Spark Generator
13
2.4.3 Servo system
14
2.4.4 Dielectric circuit
14
2.5 Types of EDM
15
2.5.1 Die-Sinking EDM
15
2.5.2 Wire Cut EDM
20
2.5.3 Electrical discharge grinding (EDG)
17
2.5.4 Electrical discharge machining small hole
17
2.6 Wire electrical discharge machining (WEDM)
19
2.6.1 Introduction of WEDM wire cut
19
2.6.2 History of WEDM
20
2.6.3 Wire-cut Machine
21
2.6.4 Wire Cut EDM Electrodes
23
2.6.4.1 Copper Wire
25
2.6.4.2 Brass Wire
25
2.6.4.3 Zinc-Coated Wire
26
2.7 Process Factors of EDM
29
2.7.1 Electrode Material
29
2.7.2 Dielectric Fluid
30
2.8 ON time, OFF time and Ip
31
2.9 Power Source
31
2.10 Measurement Method
33
2.10.1 Material Removal Rate (MRR)
33
2.10.2 Dimensional Accuracy
34
2.10.3 Surface Finish Texture
34
2.10.3.1 Surface Roughness Measurement and Specification
2.10.4 Corner Radius
35
40
2.10.4.1 Introduction to Sharp Corner
40
2.10.4.2 Causes of Inaccuracies at Sharp Corner
41
v
2.11 Wear Electrode
44
2.12 Workpiece Material
45
2.12.1 Mild Steel (Low carbon steel)
45
2.12.2 Aluminum
46
3.0 METHODOLOGY RESEARCH
47
3.1 Process Planning
47
3.2 Equipment
48
3.2.1 Wire Cut EDM (Model Mitsubishi RA 90)
3.3 Analysis Equipment
48
50
3.3.1 Digital Calliper
50
3.3.2 Optical Comparator
50
3.3.3 Surface Finish Analysis
52
3.3.4 Metallurgy Microscope (Image Analyzer)
53
3.4 Methodology Planning
55
3.5 Experiment Methodology
56
3.6 Gantt Chart
62
3.6.1 Task A
62
3.6.2 Task B
62
3.6.3 Task C
62
3.6.4 Task D
63
3.6.5 Task E
63
3.6.6 Task F
63
3.6.7 Task G
63
3.6.8 Task H
63
3.6.9 Task I
64
3.6.10 Task J
64
3.6.11 Task K
64
3.6.12 Task L
64
vi
4.0 RESULT
65
4.1 Setting Condition of E 932
65
4.2 Influence of Wire Tension
65
4.2.1 For Mild Steel
65
4.2.2 For Aluminum
67
4.3 Influence of Wire Speed
68
4.3.1 For Mild Steel
68
4.3.2 For Aluminum
69
4.4 Results for Corner Radius
71
4.4.1 For Mild Steel
71
4.4.2 For Aluminum
74
5.0 DATA ANALSIS AND DISCUSSION
76
5.1 Influence of Wire Tension
5.1.1 For Mild Steel
76
77
5.1.2 For Aluminum
83
5.1.3 Influents of Wire Tension
89
5.1.3.1 Dimensional Accuracy
89
5.1.3.2 Effect of Wire Tension to Surface Roughness
90
5.2 Influence of Wire Speed
5.2.1 For Mild Steel
93
5.2.2 For Aluminum
99
5.2.3 Influence of Wire Speed
105
5.2.3.1 Dimensional Accuracy
105
5.2.3.2 Surface Roughness
106
5.2.3.3 Effect of Wire Speed to Corner Radius
106
5.3 Influence of Current Peak (Ip)
107
5.3.1
For Mild Steel (With Wire Tension, WT)
108
5.3.2
For Aluminum (With Wire Tension, WT)
110
5.3.3
Mild Steel (With Wire Speed)
116
5.3.3.1 Dimensional Accuracy
116
5.3.3.2 Surface Roughness
117
5.3.3.3 Corner Radius
118
vii
5.4 Influence of Material
5.4.1
119
EDM Wire-Cut Machining Base on Material
123
5.4.1.1
For Mild Steel
123
5.4.1.2
For Aluminum
124
6.0 CONCLUSION AND RECOMMENDATION
6.1 Recommendation
125
130
7.0 REFERENCE
131
8.0 APPENDIX
133
viii
LIST OF FIGURES
2.1
Electric discharge machining sparking gap
7
2.2
Basic components of EDM
8
2.3
Sparking occurs at closest points between the electrode and
9
workpiece
2.4
Next spark occurs of closest points between electrode one
9
workpiece8g
2.5
Spark occurs within a column of ionized dielectric fluid
10
2.6
Spark ON: electrode and workpiece material vaporized
11
2.7
Spark OFF: vaporized cloud suspended in dielectric fluid
11
2.8
Spark-OFF: vaporized cloud solidifies to form EDM chip
12
2.9
Basic Elements of an EDM system
13
2.10
Die Sinking or penetration
15
2.11
Wire electrical discharge machining (WEDM)
16
2.12
Electrical discharge grinding (EDG)
17
2.13
Small Hole EDM Drilling
18
2.14
Wire electrical discharge machining (WEDM) Products
19
2.15
Basic wire-cut EDM machine
21
2.16
Basic features of wire-EDM
22
2.17
Wire-cut electrode wear
24
2.18
Brass electrode wire for EDM wire cut machine
25
2.19
Double-boiler principle
27
2.20
Vaporized zinc reduces electrode temperature
27
2.21
Surface characteristics
35
2.22
Surface Roughness Measuremnt
35
2.23
The Arithmetic Mean Value, Ra
36
2.24
Shows the error of corner is defined and presented
40
2.25
Show schematic representation of the wire-EDM during cutting.
42
Illustrates the wire deformation during a rough cut
3.1
Inside the EDM wire cut machine
49
ix
3.2
Wire Cut EDM (Model Mitsubishi RA 90)
49
3.3
Digital Calliper
50
3.4
Optical Comperator
51
3.5
Surface roughness tester (Model Mitutoyo SJ 301)
52
3.6
Metallurgy Microscope (Image Analyzer)
54
3.7
Axio imager accept a wide range of high contrast objectives
54
3.8
Methodology Planning Flow Chart
55
3.9
Lab or Work Machining Flow Chart
56
3.10
The suitable jig is very important for the machining
57
3.11
CAD/W software
58
3.12
The dimension of the sample
58
3.13
Shows the cutting path of the materials
61
4.1
Corner radius for peak current 8 and wire speed 2
71
4.2
Corner radius for peak current 8 and wire speed 4
72
4.3
Corner radius for peak current 4 and wire tension 4
72
4.4
Corner radius for peak current 6 and wire tension 8
73
4.5
Corner radius for peak current 4 and wire tension 4
74
4.6
Corner radius for peak current 8 and wire tension 8
74
4.7
Corner radius for peak current 6 and wire tension 4
75
4.8
Corner radius for peak current 8 and wire tension 2
75
5.1(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 4 (Mild Steel)
77
5.1(b)
Graph Surface Roughness vs Wire Tension for Ip 4 (Mild Steel)
77
5.1(c)
Graph Corner Radius vs Wire Tension for Ip 4 (Mild Steel)
78
5.2(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 6 (Mild Steel)
78
5.2(b)
Graph Surface Roughness vs Wire Tension for Ip 6 (Mild Steel)
79
5.2(c)
Graph Corner Radius vs Wire Tension for Ip 6 (Mild Steel)
79
5.3(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 8 (Mild Steel)
80
5.3(b)
Graph Surface Roughness vs Wire Tension for Ip 8 (Mild Steel)
80
5.3(c)
Graph Corner Radius vs Wire Tension for Ip 8 (Mild Steel)
81
5.4(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 12(Mild
81
Steel)
5.4(b)
Graph Surface Roughness vs Wire Tension for Ip 12 (Mild Steel)
82
5.4(c)
Graph Corner Radius vs Wire Tension for Ip 12 (Mild Steel)
82
x
5.5(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 4
83
(Aluminum)
5.5(b)
Graph Surface Roughness vs Wire Tension for Ip 4
83
(Aluminum)
5.5(c)
Graph Corner Radius vs Wire Tension for Ip 4 (Aluminum)
84
5.6(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 6
84
(Aluminum)
5.6(b)
Graph Surface Roughness vs Wire Tension for Ip 6 (Aluminum)
85
5.6(c)
Graph Corner Radius vs Wire Tension for Ip 6 (Aluminum)
85
5.7(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 8
86
(Aluminum)
5.7(b)
Graph Surface Roughness vs Wire Tension for Ip 8 (Aluminum)
86
5.7(c)
Graph Corner Radius vs Wire Tension for Ip 8 (Aluminum)
87
5.8(a)
Graph Dimensional Accuracy vs Wire Tension for Ip 12
87
(Aluminum)
5.8(b)
Graph Surface Roughness vs Wire Tension for Ip 12 (Aluminum)
88
5.8(c)
Graph Corner Radius vs Wire Tension for Ip 12 (Aluminum)
88
5.9(a)
Graph Dimensional Accuracy vs Wire Speed for Ip 4 (Mild Steel)
93
5.9(b)
Graph Surface Roughness vs Wire Speed for Ip 4 (Mild Steel)
93
5.9(c)
Graph Corner Radius vs Wire Speed for Ip 4 (Mild Steel)
94
5.10(a) Graph Dimensional Accuracy vs Wire Speed for Ip 6 (Mild Steel)
94
5.10(b) Graph Surface Roughness vs Wire Speed for Ip 6 (Mild Steel)
95
5.10(c) Graph Corner Radius vs Wire Speed for Ip 6 (Mild Steel)
95
5.11(a) Graph Dimensional Accuracy vs Wire Speed for Ip 8 (Mild Steel)
96
5.11(b) Graph Surface Roughness vs Wire Speed for Ip 8 (Mild Steel)
96
5.11(c) Graph Corner Radius vs Wire Speed for Ip 8 (Mild Steel)
97
5.12(a) Graph Dimensional Accuracy vs Wire Speed for Ip 12 (Mild Steel)
97
5.12(b) Graph Surface Roughness vs Wire Speed for Ip 12 (Mild Steel)
98
5.12(c) Graph Corner Radius vs Wire Speed for Ip 12 (Mild Steel)
98
5.13(a) Graph Dimensional Accuracy vs Wire Speed for Ip 4 (Aluminum)
99
5.13(b) Graph Surface Roughness vs Wire Speed for Ip 4 (Aluminum)
99
xi
5.13(c) Graph Corner Radius vs Wire Speed for Ip 4 (Aluminum)
100
5.14(a) Graph Dimensional Accuracy vs Wire Speed for Ip 6 (Aluminum)
100
5.14(b) Graph Surface Roughness vs Wire Speed for Ip 6 (Aluminum)
101
5.14(c) Graph Corner Radius vs Wire Speed for Ip 6 (Aluminum)
101
5.15(a) Graph Dimensional Accuracy vs Wire Speed for Ip 8 (Aluminum)
102
5.15(b) Graph Surface Roughness vs Wire Speed for Ip 8 (Aluminum)
102
5.15(c) Graph Corner Radius vs Wire Speed for Ip 8 (Aluminum)
103
5.16(a) Graph Dimensional Accuracy vs Wire Speed for Ip 12(Aluminum)
103
5.16(b) Graph Surface Roughness vs Wire Speed for Ip 12 (Aluminum)
104
5.16(c) Graph Corner Radius vs Wire Speed for Ip 12 (Aluminum)
104
5.17(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WT)
108
5.17(b) Graph Surface Roughness vs Peak Current, Ip (With WT)
108
5.17(c) Graph Corner Radius vs Peak Current, Ip (With WT)
109
5.18(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WT)
109
5.18(b) Graph Surface Roughness vs Peak Current, Ip (With WT)
110
5.18(c) Graph Corner Radius vs Peak Current, Ip (With WT)
110
5.19(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WS)
111
5.19(b) Graph Surface Roughness vs Peak Current, Ip (With WS)
111
5.19(c) Graph Corner Radius vs Peak Current, Ip (With WS)
112
5.20(a) Graph Dimensional Accuracy vs Peak Current, Ip (With WS)
112
5.20(b) Graph Surface Roughness vs Peak Current, Ip (With WS)
113
5.20(c) Graph Corner Radius vs Peak Current, Ip (With WS)
113
5.21(a) Graph Dimensional Accuracy vs Wire Tension (Base on Material)
120
5.21(b) Graph Surface Roughness vs Wire Tension (Base on Material)
120
5.21(c) Graph Corner Radius vs Wire Tension (Base on Material)
121
5.22(a) Graph Dimensional Accuracy vs Wire Speed (Base on Material)
121
5.22(b) Graph Surface Roughness vs Wire Speed (Base on Material)
122
5.22(c) Graph Corner Radius vs Wire Speed (Base on Material)
122
8.1
Clamping the workpiece
133
8.2
Optical Comparator Value panel
133
8.3
Surface roughness tester
133
8.4
Edm Control Panel Screen
133
xii
8.5
EDM Control Panel
134
8.6
Optical Comparator Image
134
xiii
LIST OF TABLES
2.1
Show appropriate wire type for different application
28
2.2
Advantage and disadvantage type of power source
32
2.3
ISO standard Ra value for common manufacturing method
38
3.1
Table for constant EDM wire cut parameters
60
3.2
Table of function and setting range for EDM wire cut constant parameter
60
3.3
Gantt Chart of the Project
65
4.1
Machining Constants Parameters
65
8.1
Table of Parameters for Mitsubishi WEDM RA Series
xiv
135
LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED
NOMENCLATURE
PS
Function to set the power supply mode
V0
Main power supply voltage
OFF
Pulse OFF time
SA
Stabilizer A; to make machining speed will be faster
SB
Stabilizer B; high value, the slower the machining will be
SC
Stabilizer C; machining for finishing circuit
SE
Stabilizer E; used particularly for 1st cut machining
VG
Voltage Gap; to set average machining voltage used
Ip
Peak Current
WS
Wire Speed
WT
Wire tension
xv
CHAPTER 1
INTRODUCTION
1.1
Background
Machining is an importance process in manufacturing engineering. It is dividing by two
methods to say conventional machining and unconventional machining. For example of
the conventional machining are milling, drilling and lathe. According this method, the
quality of production are depend of efficiency operator, type of process is choosing and
type of material is used. Also get in certain case where the conventional machining is not
suitable to applicable. Such as an example where the shape we want to produced are
complicated. It is because to producing the complicated partial are need high cost and a
long of producing time. Furthermore in a modern technology, get a various new material
from other sources. It is shown indeed we need a new method for improvement and
upgrading the quality of metal machining. So that, to solve this problem we need
unconventional machining for exceed the weakness by unconventional machining is
better if the parameter choosing is better. It is because this method is limited for certain
parameter only. Electrical discharge machining EDM is one of the most accurate
manufacturing methods of working exceptionally hard metals and other materials that are
difficult to machine cleanly with more conventional methods. EDM is a process of
elimination that erodes or removes metal and material in the path of electrical discharges
that form an arc between an electrode tool and the workpiece until the desired part is
attained. Using this process is extremely accurate, reliable and affordable, so it is
becoming an increasingly popular choice for many companies. But refers to the demand
of the industries that need very accuracy products so the EDM process must be have an
improvement process and research time to time so it can fulfill the demand of the
industries.
1
1.2
Problem Statement
In machining process, it is very important to get optimum cutting result where it can
reduce cutting time, reduce the wear of electrode, save the operation cost, save the
material cost, perfect sharp corner cutting with high accuracy dimensional and finishing
with a good surface texture. But then, the problem will be occurs is finishing surface
texture are not good and unsatisfactory. Also for sharp corner cutting the have many
errors will occurs. In industry actually sharp corner must be avoided because of it
difficult to produce with high accuracy but the problem will occurs when the product
need the sharp corner machining. The problem also included how to find the best
machining parameter for sharp corner cutting that will be reach to the best result of sharp
corner cutting.
1.3
Objective of Study
The purposes of this study are:
(a) To study the cutting process of sharp corner
(b) To study the relationship of sharp corner angle, surface roughness and
dimensional accuracy and workpiece material.
(c) To propose the optimum condition for machining sharp corner.
1.4
Scope and Limitation
For this study, EDM wire cut (Model Mitsubishi RA 90) will be used in CNC laboratory in
UTeM. The result of this study just suitable for this EDM wire cut (Model Mitsubishi RA 90) and
not applicable to other types of EDM wire cut or other project. Overall the project is taken as long as
5 month which is started on December 2007 until April 2008. The early choice of wire electrode is
brass wire with diameter 0.25mm. The material that will be used is mild steel and aluminum with the
thickness is 10mm.
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1.5
Important of Study
The important of this study is as follows:
(a) To fine the best method and parameters to produce the high accuracy of sharp
corner cutting using EDM wire cut machine (Model Mitsubishi RA 90).
(b) To fine the improvement method for produce good surface finish and high accuracy of
dimensional using EDM wire cut machine (Model Mitsubishi RA 90).
(c) Can reduce the damage of the material and the machine when the machining
process.
(d) Will be a reference for academic studies which is related to EDM wire cut
machining (Model Mitsubishi RA 90).
1.6
Outline of Study
Overall this report is divided into 5 chapters. For Chapter 1 is mainly describe about the
introduction which is highlight to background, problem statement, objective of study,
scope and limitation, important of study and study outline. Chapter 2 is the literature
review which in this chapter will discuss the definition and the introduction of EDM wire cut
generally includes the operation of the machine. This chapter also will discuss the characteristic
and the basic concept of EDM machining. Then, Chapter 3 is describing about methodology of
this study. This chapter will discuss the process planning, parameter of machining and types of
material. This chapter also will describe about the specification of EDM wire cut (Model
Mitsubishi RA 90) that will be uses for the study and the measurement apparatus. For Chapter 4
is result and discussion of the study observation. This chapter will compile all the result and the
result will be form into graphs to be analyzed. The result will be discussed also in this chapter.
Chapter 6 will shown the conclusion and the recommendation of the whole this project that has
been done.
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