Development Of Welding Aid Kit For Shielded Metal Arc Flat Welding.

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA

DEVELOPMENT OF WELDING AID KIT

FOR SHIELDED METAL ARC FLAT

WELDING

Thesis submitted in accordance with the requirements of the

Universiti Teknikal Malaysia Melaka for the

Bachelor of Engineering Manufacturing (Manufacturing Process)

By

NUR AZIZULHAKIM BIN ZAKARIA

B050310009

Faculty of Manufacturing Engineering

May 2007

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APPROVAL

This thesis submitted to the senate of UTeM and has been accepted as partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering (Manufacturing Process). The members of the supervisory committee

are as follow:

……… Main Supervisor

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DECLARATION

I hereby, declare this thesis entitled “Development of Welding Aid Kit for Shielded Metal Arc Flat Welding” is the results of my own research except as cited in the

reference.

Signature :………

Author’s Name : NUR AZIZULHAKIM BIN ZAKARIA

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ABSTRACT

This thesis contains the development of welding aid kit for shielded metal arc flat welding. The purpose of this thesis are mainly about to understand on welding parameters and hence to develop with a product so that problems that may arise from it can be solved. It also explains about the common arc welding process that usually incorporates inside the part that is about to be processed, how to identify, how to tackle the problem and what solutions are available. Common problem that arise when use this welding operation are hard to maintain the arc length, hard to control the electrode angle when the electrode decrease and inconsistently of travel speed when doing this operation. Main objective is to study of all the parameters and to design a product to make sure that all the parameters can be control when doing the operation. A few solutions to welding process were identified throughout the thesis with details on each one. A product which contains the mechanical movement is chosen and designed to be associated with the welding parameter. Based on the current technologies, the welding aid kit was designed to solve two main problems that are to constant the travel speed and the arc length. The design development of the welding aid kit consists of the arm and base of the product. Few features that were necessary to the design are railway, mechanical part, connector and holder for electrode holder. After the design process, all the manufacturing costs and product specification was stated using some method including Design for Manufacturing (DFM), Design for Assembly (DFA), screening method and design selection criteria. Results from this project have solved the process of designing the welding aid kit and some physical calculation for the design. Thus, for the precise movement, the best mechanism used includes the electronic device system.

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ABSTRAK

Tesis ini mengandungi penerangan mengenai tajuk projek iaitu pembangunan bagi alat bantuan kimpalan untuk kimpalan jenis arka yang diaplikasi pada proses kimpalan arka bagi bahan kerja yang mempunyai permukaan rata. Tujuan utama adalah untuk mengkaji pembangunan alat bantuan tersebut seiring dengan pemahaman mengenai parameter-parameter bagi proses kimpalan untuk menyelesaikan masalah yang dihadapi. Ini juga dapat menerangkan mengenai proses kimpalan arka dan cara-cara untuk mengatasi masalah yang dihadapi, cara untuk mengenal pasti masalah dan juga cara untuk mengatasi masalah yang dihadapi dengan berkesan. Masalah yang kerap kali berlaku semasa proses ini ialah sukar untuk mengekalkan jarak antara elektrod dan permukaan benda kerja, sukar untuk mengekalkan sudut elektrod apabila elektrod semakin pendek dan kesukaran untuk mengekalkan kelajuan pergerakan tangan semasa operasi dijalankan. Objektif utama tesis ini adalah untuk mengkaji parameter semasa menjalankan operasi kimpalan arka dan juga mereka alat bantuan bagi memudahkan pengguna untuk mengawal semua parameter tersebut semasa menjalankan oerasi tersebut. Beberapa cara mengatasi masalah akan dikenal pasti sepanjang pembangunan produk tersebut. Pilihan produk yang dikaji mengandungi pergerakan secara mekanikal yang berasaskan segala parameter yang sedia ada pada proses kimpalan arka. Berdasarkan kepada teknologi terkini, produk ini direka untuk menyelesaikan dua masalah utama iaitu untuk mengekal kelajuan kimpalan dan juga jarak antara elektrod dan permukaan bahan kerja. Bahagian utama dalam produk ini ialah lengan produk dan juga badan utama produk. Bahagian tambahan untuk menambah lagi baikan produk ialah landasan, bahagian mekanikal, penyambungan dan juga pemegang bagi ‘electrode holder’. Selepas mereka bentuk produk, kesemua kos-kos pembuatan dan juga spesifikasi produk perlu ditentukan menggunakan langkah seperti Rekabentuk

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untuk pembuatan (DFM), Rekabentuk untuk penyambungan (DFA), langkah ‘Screening’ dan juga kriteria untuk memilih rekabentuk. Projek ini telah menyelesaikan beberapa masalah contohnya dalam merekabentuk produk dan juga pengiraan berdasarkan bentuk fizikal unutk rekabentuk tersebut. Dalam pada itu, untuk mendapatkan pergerakan mekanikal yang lebih jitu, alat-alat tambahan seperti sistem elektronik perlulah ditambah pada masa hadapan.

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DEDICATION

For all your advice and encouragement, this thesis is gratefully dedicated to my family, Mr Shahir Bin Kasim, and my friends. Thank you very much for your continuous support and effort towards the publication of this thesis.

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ACKNOWLEDGEMENTS

Alhamdulillah, thank to Allah because I finish my PSM report in the duration time given.

Firstly, I would like to thank to my supervisor; Mr. Mohd Shahir Bin Kasim as my supervisor and Mr. Zulkarnain Bin Marjom as my second reader because of his guidance and help me along this project that have done.

I’m also like to thank to all my friend for all the information that given to me to complete my PSM report. I also would like to appreciate to all the participation that involved during this report is done.

Finally, I would like to thank to my family because give me moral support to complete this report.

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APPROVAL ...i DECLARATION ...ii ABSTRACT...iii ABSTRAK...iv DEDICATION...vi ACKNOWLEDGEMENTS...vii

TABLE OF CONTENTS...viii

LIST OF FIGURES ...xii

LIST OF TABLES...xiv

LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED NOMENCLATURE ... xv

CHAPTER 1 ... 1

INTRODUCTION ...1

1.1 Introduction...1

1.1.1 Current issues...2

1.2 Problem statement...2

1.3 Current Technologies...3

1.4 Objectives ...4

1.5 Scope of the study...4

1.6 Thesis Organization ...4

CHAPTER 2 ... 6

LITERATURE REVIEW ...6

2.1 Introduction to shielded metal arc welding...6

2.2 Position of welding ...8

2.3 Parameters for arc welding ...9

2.3.1 Arc length ...10

2.3.2 Travel speed...11

2.3.3 Amperage...15

2.3.4 Arc voltage...16

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2.5 Computer controlled robot...18

2.6 Development during 1990’s...20

2.7 Technological challenges related to robotic welding ...21

2.8 Robotic arc welding ...24

2.9 Current Technologies of Welding Aid Kit ...28

CHAPTER 3 ... 30

METHODOLOGY ...30

3.1 Introduction...30

3.2 Flow Chart ...31

3.3 Comparison of the Sketchers ...34

3.3.1 First sketch...35

3.3.2 Second sketch ...36

3.3.3 Third sketch ...37

3.3.4 Fourth sketch...38

3.4 Selection method...38

3.4.1 Design for Manufacturing (DFM) ...38

3.4.2 Design for Assembly (DFA)...39

3.5 Development process...40

3.5.1 Product development process flows ...42

CHAPTER 4 ... 43

DESIGN...43

4.1 Introduction...43

4.2 Concept selection...43

4.2.1 First sketch...44

4.2.2 Second sketch ...45

4.2.3 Third sketch ...46

4.2.4 Fourth sketch...47

4.3 Design Selection Criteria ...48

4.4 Design selection...49

4.4.1 Concept screening...49

4.5 Product specification...51

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4.5.2 Purpose...52

4.5.3 Special or new features ...52

4.5.4 Competition ...52

4.5.5 Market suggestion...52

4.5.6 Relationship to existing product line ...53

4.5.7 Market need ...53

4.5.8 Cost ...53

4.5.9 Environment...53

4.5.10 Safety ...54

4.5.11 Standard ...54

4.6 Detailed drawing...54

4.7 Material selection...55

4.7.1 Material selection cost ...56

4.7.2 Selected material for each part...57

4.8 Project cost...58

4.8.1 Cost analysis ...58

4.8.2 Manufacturing cost ...59

4.8.3 Total manufacturing cost ...60

4.9 Conclusion ...60

CHAPTER 5 ... 61

ANALYSIS...61

5.1 Introduction...61

5.2 Analysis using Working Model ...61

5.2.1 Simple analysis of moment...61

5.3 Analysis about the drawing...66

5.4 Analysis using MDesign...69

5.4.1 Worm gear analysis ...69

5.4.2 Spur gear analysis ...72

5.5 Analysis using CosmoXpress ...76

5.5.1 Base...76

5.6 Conclusion ...77

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FINAL DESIGN ...78

6.1 Introduction...78

6.2 Assembly drawing ...78

CHAPTER 7 ... 81

DISCUSSION...81

CHAPTER 8 ... 83

CONCLUSION AND RECOMMENDATIONS ...83

8.1 Conclusion ...83

8.2 Recommendations...84

REFERENCES ... 85

APPENDICES ... 87

APPENDIX A...87

Isometric Drawing ...87

APPENDIX B ...96

Assembly drawing ...96

APPENDIX C ...98

Working model simulation ...98

APPENDIX D...103

Gantt Chart for PSM I...103

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LIST OF FIGURES

Figure 1.1: Typical jointed-arm robot... 3

Figure 2. 1: Schematic illustration of the shielded metal-arc welding operation [4]... 7

Figure 2. 2: Hand position in the welding processes [4]. ... 7

Figure 2. 3: Comparison of the electrode angle [6]. ... 8

Figure 2. 4: Suitable angle for flat welding for metal shielded arc welding [6]... 9

Figure 2. 5: Definition of arc length [5]... 10

Figure 2. 6: Comparison of the arc length [5]... 10

Figure 2. 7: Travel speed limit for current level used for 1/8-inch-diameter E6010 SMAW electrode [6]... 11

Figure 2. 8: Travel speed limit for current level used for 1/8-inch-diameter E6011 SMAW electrode [6]... 12

Figure 2. 9: Travel speed limit for current level used for 1/8-inch-diameter E6013 SMAW electrode [6]... 12

Figure 2. 10: Travel speed limit for current level used for 1/8-inch-diameter E7018 SMAW electrode [6]... 13

Figure 2. 11: Travel speed limit for current level used for 1/8-inch-diameter E7024 SMAW electrode [6]... 13

Figure 2. 12: Travel speed limit for current level used for 1/8-inch-diameter E8018 SMAW electrode [6]... 14

Figure 2. 13: Travel speed limit for current level used for 1/8-inch-diameter E11018 SMAW electrode [6]... 14

Figure 2. 14: Comparison of the travel speed [5]. ... 15

Figure 2. 15: Graph shown the preferred current level for different of electrode size [3]... 16

Figure 2. 16: Arm type [20]. ... 18

Figure 2. 17: Example of robot station with double positional [19]... 19

Figure 2. 18: Example of robot station with gantry [19]. ... 20

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Figure 2. 20: ‘Motovator’ [20]... 25

Figure 2. 21: Inside the motor [20]. ... 26

Figure 2. 22: Shoulder [20]... 26

Figure 2. 23: ‘Maxon’ [20]. ... 27

Figure 2. 24: Movement of the robot welding [20]. ... 28

Figure 2. 25: Submerged-arc head mounted on self-propelled, self-guiding tractor [21]... 29

Figure 3. 1: First sketch. ... 35

Figure 3. 2: Second sketch... 36

Figure 3. 3: Third sketch... 37

Figure 3. 4: Fourth sketch. ... 38

Figure 3. 5: The generic product development process [23]. ... 40

Figure 3. 6: Process flow diagram for three product development processes [23]... 42

Figure 4. 1: First concept. ... 44

Figure 4. 2: Second concept... 45

Figure 4. 3: Third concept... 46

Figure 4. 4: Fourth concept... 47

Figure 5. 1: Rotational motor 0°. ... 62

Figure 5. 2: Rotational motor -2.865°... 63

Figure 5. 3: Rotational motor -5.730°... 63

Figure 5. 4: Rotational motor -11.459°... 64

Figure 5. 5: Rotational motor –22.918°. ... 64

Figure 5. 6: Rotational motor -48.70°... 65

Figure 5. 7 : Analysis of the base... 76

Figure 6. 1: Assembly drawing with dimension ... 78

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LIST OF TABLES

Table 2. 1: Electrode angles for manual arc welding [6]... 8

Table 2. 2: Established voltage limit for different electrode [3]... 16

Table 3. 1: Generic development process compare with flow chart of methodology . 41 Table 4. 1: Criteria of design selection ... 48

Table 4. 2: Screening concept... 50

Table 4. 3: Characteristic and application of the selected material. ... 55

Table 4. 4: Material cost. ... 56

Table 4. 5: Selected material for each part and its reason. ... 57

Table 4. 6: Estimation cost for all the material... 58

Table 5. 1: Parts in the design... 66

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LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED

NOMENCLATURE

DFM - Design for Manufacturing

DFA - Design for Assembly

SMAW - Shielded Metal Arc Welding

FKP - Fakulti Kejuruteraan Pembuatan

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CHAPTER 1 INTRODUCTION

1.1 Introduction

Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the work pieces and adding a filler material to form a pool of molten material that cools to become a strong joint, but sometimes pressure is used in conjunction with heat, or by itself, to produce the weld [1]. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the work pieces to form a bond between them, without melting the work pieces.

Arc welding processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and filler material is sometimes used as well.

Welding aid kit can be as a guide to make sure that the beginner users can make a good quality of welding. There are some parameters must be concentrate to make sure that a good quality of welding cab be produced. These parameters are involved when doing the arc welding process. Two main parameters must be constantly do are travel speed and arc length.

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1.1.1 Current issues

Arc welding is mostly used with the skills of the users to make the good quality of the welding. Many techniques are created to make the easiest way to weld the joining method. As we can see, the experienced users are able to make a good quality of the welding. But, it certain time, when the users in fatigue or not in concentration, they also can make the mistake of the welding. As the result, bad quality of welding is performed by the users. Meanwhile, for the new user, they must learn the basic term of the welding before start the operation. It is hard to get the good quality of welding when it use for the first time. New users must practice frequently to get the right rhythm of the welding.

1.2 Problem statement

Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding is one of the oldest, simplest and most versatile joining method. This welding process uses a consumable coated electrode. During process, arc is formed at the small gap between the electrode and the work piece resulting high temperatures causing the work piece and the electrode to melt [2].

Basically, this project will be done based on these problem statements:

1. For the beginner user, the main cause is hard to maintain arc distance where too much distance will cause poor welding.

2. The speed when move the welding holder is exactly influences the quality of the welding.

3. For the flat surface or the straight line, consistency is difficult to obtain and that will cause the bad quality of welding.

4. Beginner must always practice use this type of welding processes to get the best quality of the welding.

As we know, a lot of manual instructions are available to make the easiest way of the welding for the new users. But, it stills a lot of difficulty to study the term of manual

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instruction. Position of hand, the speed of the hand and timing of the gap between electrode and work piece must be studied to make sure that less defect can be make after the welding process. As the solution for the problem statement, a development of welding aid kit are made to make sure that user can get the easiest way to use this welding processes.

1.3 Current Technologies

Nowadays, a new technology of robot is manipulated into the welding system. Robots take many forms but are essentially mechanized devices which can repeat a sequence of operations with a high degree of consistency. In the welding shop, a robot is a manipulating tool which moves the welding head along the joint line but at the same time maintains the correct relationship between the welding gun and the work. The robot can do this only if it given instructions, so there must be a facility to program the complete welding sequence, including control of the welding parameters. Ideally, there should be some form of feedback, so that the robot can check that it is welding in the right place.

Figure 1.1: Typical jointed-arm robot.

As we mentioned above, this project is related to make a development of welding aid kit for shielded metal arc flat welding. It also can give the opportunity to explore about the welding processes especially for the speed of hand movement and the gap

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between electrode and work piece. This all parameters are influence in developing the aid kit for the welding method.

1.4 Objectives

1. To design this welding aid kit for flat surface of work piece.

2. To study about current design of welding aid kit to develop into SMAW welding process.

1.5 Scope of the study

There is much type of skills when using this type of welding processes especially in straight and flat welding. The main cause that influences the process is the skills of the users. Users must maintain the distance from the electrode to the work piece. As the result, we can see the comparison of output between human skills and the device. Study of the selected design must include all the product specification and the manufacturing cost to produce the product. Development of the product must consist the usage of the drawing software; ‘Solid Work’ and simulation; ‘Working Model’ to calculate the physical terms of the product.

1.6 Thesis Organization

For the thesis, it consists 6 chapters:

1. Chapter 1 introduce about the welding, Shielded Metal-Arc welding, objectives and scope of the project.

2. Chapter 2 reviews about the literature on the journals, books and internet. The area covered the rate of the electrode, method of basic principle to move the kit and the tolerance between electrode and work piece.

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3. Chapter 3 describes methodology to develop this welding aid kit and the requirement to ensure that this welding aid kit work based on the chosen electrode, tolerance between electrode and work piece and time when electrode decrease.

4. Chapter 4 describes the design selected. It includes the product specification; all the costs involve and design criteria.

5. Chapter 5 shows the analysis of the design and the calculation of physical terms; it uses ‘Working Model’ simulation. For the strength of the material, it uses ‘CosmoXpress’ simulation and for the gearing system, it uses ‘MDesign’ software to calculate it.

6. Chapter 6 evaluates about final design. It includes the drawing for all the components and the selected material for each component.

7. Chapter 7 describes about discussion on the design selected.

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CHAPTER 2 LITERATURE REVIEW

2.1 Introduction to shielded metal arc welding

Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld [1]. An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.

Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of steel structures and in industrial fabrication [3]. The process is used primarily to weld iron and steels (including stainless steel) but aluminum, nickel and copper alloys can also be welded with this method.

The heat generated melts a potion of the trip of the electrode, of its coating, and of the base metal in the immediate area of the arc. A weld forms after the molten metal, a mixture of the base metal (work piece), the electrode metal and substances from the coating on the electrode, solidifies in the weld area. The electrode coating deoxidizes

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the weld area and provides a shielding gas to protect it from oxygen in the environment.

The polarity of the DC current that is the direction of current flow can be important; its selection depends on such factors as type of electrode, the metals to be welded and the depth of the heated zone. In straightly polarity, the work piece is positive and the electrode negative; it is preferred for sheet metals, because it produce shallow penetration and for joints with very wide gaps [4]. In reverse polarity, the electrode is positive, and deeper weld penetration is possible. In the AC method, the arc pulsates rapidly; this method is suitable for welding thick sections and for using large-diameter electrodes at maximum currents.

Figure 2. 1: Schematic illustration of the shielded metal-arc welding operation [4].

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2.2 Position of welding

Ideally, the work should be positioned during welding so that the molten weld metal is held in placed by gravity. It also enables high currents to be used, leading to faster welding. This implies that the work can be turned or manoeuvred [6]. Many fabrications do not lend themselves to this treatment, and much of the welding in industry is done ‘in position’. The welder controls the weld by lowering the heat input to reduce the fluidity and to give a small pool which solidifies before it has time to run out of the joint. At the same time, the direction of the arc, i.e. the angle between the electrode and the weld surface, can be varied to position the weld pool to the best advantage.

Table 2. 1: Electrode angles for manual arc welding [6].

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