UNIVERSITI TEKNIKAL MALAYSIA MELAKA

STUDIES ON SURFACE CLEANING METHOD FOR BEST

STRENGTH OF SPOT WELDING

This report is submitted in accordance with the requirement of Universiti Teknikal

Malaysia Melaka (UTeM) for the Bachelor of Manufacturing Engineering

Technology (Process and Technology) with Honours

by

NOOR JULIZA BINTI JUNAIDI

B071310965

910729-13-5966

FACULTY OF ENGINEERING TECHNOLOGY

2016

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: Studies On Surface Cleaning Method For Best Strength Of Spot

Welding

SESI PENGAJIAN: 2016/2017 Semester 1

Saya NOOR JULIZA BINTI JUNAIDI

mengaku membenarkan Laporan PSM in idisimpan di Perpustakaan Universiti

Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan

pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan ( )

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan

atau kepentingan Malaysia sebagaimana yang termaktub

dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan

oleh organisasi/badan di mana penyelidikan dijalankan)

(________________________)

AlamatTetap:

No 112, Jalan Aru 2B, Holiday Park

98000, Miri,

Sarawak

Tarikh: ________________________

Disahkan oleh:

(_________________________)

Cop Rasmi:

Tarikh: _______________________

**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.

9 December 2016 9 December 2016

iii

DECLARATION

I hereby, declared this report entitled “Studies on Surface Cleaning Method for Best

Strength of Spot Welding” is the result of my own research except as cited in

references.

Signature : ……………………………………….

Author’s Name : Noor Juliza bt Junaidi

Date : ………………………………………..

iv

APPROVAL

This report is submitted to the Faculty of Engineering Technology of UTeM as a

partial fulfillment of the requirements for the degree of Bachelor of

Manufacturing Engineering Technology (Process and Technology) with

Honours. The member of the supervisory is as follow

……………………………….

(Mr Hanizam bin Hashim)

v

ABSTRAK

Kimplan rintangan titik kebiasaanya digunakan di dalam industry automotif, ini

disebabkan kerana manfaatnya dari segi kelajuan yang tinggi,hasil pemasangan

yang tinggi, dan sesuia dalam automasi. Keutuhan permukaan pada sesuatu bahan

mempunyai kesan yang langsung kepada kekuatan penyambungan dalam kimpalan

titik. Untuk mendapatkan kekuatan yang terbaik untuk kimpalan titik,kaedah

pembersihan memberi kesan kepada kekuatan. Dalam kaedah pembersihan,

terdapat 3 jenis pembersihan yang digunakan iaitu pembersihan kimia dengan

turpentin, pembersihan kimia dengan sabun dan pembersihan mekanikal dengan

kertas pasir. 3 ujian digunakan dalam projek ini iaitu mengunakan ujian penurunan

untuk menganalisis sudut hubungan untuk menyelidik permukaan tenaga pada

permukaan pembersihan, ujian tegangan untuk menganalisis kekuatan pada

penyambungan kimpalan titik dimana beban maksimum yang boleh dikenakan

sebelum sampel itu terpisah dua atau retak dan ujian pandangan menggunakan

caliper untuk mengukur garis pusat nugget (mm) pada sampel. Dengan membuat

analisis, kaedah pembersihan yang sesuai dapat ditentukan. Bahan yang digunakan

dalam kajian ini adalah aluminium. Akhirnya, perbezaan keputusan menunjukkan

kaedah pembersihan menggunakan Turpentine adalah yang terbaik untuk

permukaan Aluminium.

vi

ABSTRACT

Resistance spot welding is usually used in the automotive industry, because it has the

benefit which is high-production assembly lines, high speed, and suitability for

automation. The surface integrity of the material surface has direct impact to the

joining strength in spot welding. To have best strength of spot welding, the cleaning

methods affect the strength. The objective of this project is to study on the surface

cleaning method for best strength of spot welding. In the cleaning method, there are

3 type of cleaning which are chemical cleaning by turpentine, chemical cleaning by

soap and mechanical cleaning by sandpaper. 3 test are used in this project which is

using drop test to analyze the contact angle to investigate the surface energy of

cleaning surface, tensile test to analyze the strength of spot welding joining which

maximum load that can be applied before the specimen is rupture or tears apart and

visual test using calliper to measure the nugget diameter (mm) of the specimen. By

doing the analysis, the suitable cleaning method can be determined. The material

used in this study is Aluminium. Finally, the comparison result shown the cleaning

by using turpentine is the best for the aluminium surface.

.

vii

DEDICATIONS

Dedicated to my beloved father, Junaidi bin Awi and my beloved mother, Saadiah

binti Narawi

viii

ACKNOWLEDGMENTS

Alhamdulillah, thank you Allah because of His blessing, I finally complete and

finish my final year project successfully.

In the journey of the Final Year Project, I would like to express the deepest

appreciation to everyone who supported me for my Final Year Project. I am very

thankful for their guidance, cooperation, encouragement and constructive criticism to

me in order for me to complete my Final Year

First and foremost, a great appreciation to my supervisor, Engr Hanizam Bin Hashim

for his guidance, and his inspiring words to motivate me in completing the Final

Year Project. I am deeply indebted to him for his valuable guidance throughout this

thesis. I am very thankful for his inspiring words to motivate and encourage me to

finish my Final Year Project.

Furthermore, I would like to express my gratitude to technical staff, En Fakhrulnaim

Bin Ibrahim and En Azizul Ikhwan bin Mohd who willing to spend time to

demonstrate in using the machine.

Moreover, I extend my cordial thanks to Universiti Teknikal Malaysia Melaka

(UTeM) for the facilities that help me to complete my Final Year Project.

Last but not least, I am thankful to my family and friends for the abundant support

and encouragement during ups and downs and difficulties encountered during the

project

ix

TABLE OF CONTENT

Abstrak i

Abstract ii

Dedication iii

Acknowledgement iv

Table of Content v

List of Tables viii

List of Figures ix

List Abbreviations, Symbols and Nomenclatures xi

CHAPTER 1: INTRODUCTION 1

1.1 Background 1

1.2 Problem statement 2

1.3 Objective 2

1.4 Scope of the project 3

CHAPTER 2: LITERATURE REVIEW 4

2.1 Welding 4

2.2 Resistance Spot Welding 6

2.3 Principle of Spot Welding 6

2.4 Parameter for Resistance Spot Welding 8

2.4.1 Electrode force 8

2.4.2 Squeeze time 8

2.4.3 Weld or Heat Time 8

2.4.4 Hold Time (Cooling Time) 8

2.4.5 Weld current 9

2.5 Spot Welding Electrode 9

2.5.1 Electrode Material 10

2.6 Aluminium 11

2.6.1 The Chemical Composition of Aluminium Alloy 11

2.6.2 Mechanical Properties of Aluminium 12

x

2.6.3 Applications of Aluminium 12

2.7 Cleaning Method 13

2.7.1 Mechanical Method 13

2.7.2 Chemical Method 13

CHAPTER 3: METHODOLOGY 15

3.1 Flow chart 16

3.2 Selection of Machine and Material 16

3.2.1 Spot Welding Machine MULTISPOT M80 17

3.2.1.1 Specification of Spot Welding Machine 18

3.2.2 Spot Welding Machine INVERTER 15K 20

3.2.2.1 Specification of Spot Welding Machine 20

3.2.3 Welding Tip 22

3.2.4 Sand Blasting Machine 22

3.2.5 Universal Tensile Machine 23

3.2.6 Aluminium 24

3.2.7 Kerosene 24

3.2.8 Sandpaper 24

3.2.9 Soap 25

3.2.10 Turpentine 25

3.3 Conduct the Experiment 25

3.3.1 Procedure for cutting the material 25

3.3.2 Procedure for cleaning 26

3.3.2.1 Chemical Cleaning (Turpentine) 26

3.3.2.2 Chemical Cleaning (Soap) 27

3.3.2.3 Mechanical Cleaning (Sandpaper) 27

3.3.3 Procedure for Contact angle test 28

3.3.4 Procedure for Spot Welding 29

3.3.5 Procedure for Tensile Test 29

3.4 Type of Testing 30

3.4.1 Contact Angle Test 30

3.4.2 Tensile Test 32

3.4.3 T Test 32

xi

CHAPTER 4: RESULT & DISCUSSION 33

4.1 Contact Angle Analysis 33

4.1.1 Chemical Cleaning (Turpentine) 34

4.1.2 Chemical Cleaning (Soap) 35

4.1.3 Mechanical Cleaning (Sandpaper) 36

4.2 Spot Welding 38

4.3 Tensile Test 38

4.3.1 Tensile Test Data Collection 39

4.3.2 Comparison between Turpentine, Soap and Sandpaper 40

4.4. T-Test 42

4.4.1 Turpentine vs. Soap 42

4.4.2 Turpentine vs. Sandpaper 44

4.4.3 Soap vs. Sandpaper 46

4.5 Comparison of Contact Angle and Maximum Force 49

4.6 Nugget diameter 50

CHAPTER 5: CONCLUSION AND RECOMMENDATION 52

5.1 Conclusion 52

5.2 Recommendation for Future Research 53

REFERENCES

APPENDICES

A Tensile Test Result

B Cutting Material

C Cleaning Process

D Contact Angle Analysis

E Spot Welding

F Tensile Test

G Contact Angle Result

H Gantt Chart

xii

LIST OF TABLE

2.1 Chemical composition of Aluminium AA1100 12

2.2 Mechanical properties of Aluminium 12

3.1 Specification of the Spot Welding Machine MULTISPOT M80 18

3.2 Specification of the Spot Welding Machine INVERTER AS25-13K 20

3.3 Sample for Contact angle Test 28

3.4 Samples for Tensile Test 30

4.1 Contact Angle Analysis for Turpentine cleaning 34

4.2 Contact Angle Analysis for Soap cleaning 35

4.3 Contact Angle analysis for sandpaper cleaning 36

4.4 Parameter of spot welding 38

4.5 Tensile test of Aluminium by chemical cleaning (Turpentine) 39

4.6 Tensile test of Aluminium by chemical cleaning (Soap) 40

4.7 Tensile test of Aluminium by chemical cleaning (Sandpaper) 40

4.8 Average of Maximum Force and Contact Angle 49

4.9 Welding nugget of 3 type cleaning method 51

xiii

LIST OF FIGURES

2.1 Classification of Welding and Joining Process 5

2.2 Resistance Spot Welding with work piece 6

2.3 Resistance Spot Welding 7

2.4 Steps in making spot weld 7

2.5 The six common electrode face designs for spot welding 10

2.6 Two piece electrode cap and adaptors 10

3.1 Flow Chart 16

3.2 Spot Welding Machine MULTISPOT M80 17

3.3 Spot Welding Machine INVERTER AS25-13k 20

3.4 Electrode tip 22

3.5 Sand blasting machine 23

3.6 Universal testing machine 23

3.7 Cutting the Aluminium 26

3.8 Cleaning aluminium using Turpentine 26

3.9 Cleaning aluminium using soap 27

3.10 Cleaning aluminium using sandpaper 27

3.11 Dimensional detail for Resistance Spot Welding 29

3.12 Contact angle Definition 30

3.13 Contact Angle 31

4.1 Average of contact angle for cleaning surface 37

4.2 Marking the specimen 38

4.3 Specimen place on the machine 39

4.4 Average Maximum Force 41

4.5 Mean of Turpentine and Soap 42

4.6 Five samples data of Turpentine and Soap 43

4.7 Output of two samples T-Test (Turpentine and Soap) 43

4.8 Mean of Turpentine and Sandpaper 44

4.9 Five samples data of Turpentine and Sandpaper 45

xiv

4.10 Output of two samples T-Test (Turpentine and Sandpaper) 45

4.11 Mean of Soap and Sandpaper 46

4.12 Five samples data of Soap and Sandpaper 47

4.13 Output of two samples T-Test (Soap and Sandpaper) 47

4.14 Maximum Force vs. Contact Angle 49

4.15 Nugget pullout failure 50

4.16 Figure 4.16: Interfacial failure 51

xv

LIST OF ABBREVIATIONS, SYMBOLS AND

NOMENCLATURES

CC1₄ - Carbon tetrachloride

C₂ HCI₃ . - Trichloroethylene

kVA - Kilovolt-amp

kA - Kilo ampere

s - Second

% - Percent

Hz - Hertz

V - Voltage

A - Ampere

ºC - Degree Celsius

º - Degree

mm - Millimetre

mm² - Square millimetre

m/s - meter per second

kg - kilogram

in - inch

M Pa - Mega Pascal

daN - Decanewton

α - Alpha

1

CHAPTER 1

INTRODUCTION

1.0 Introduction

This chapter will explain about the general information of the study,

background, problem statements, objectives, and scope.

1.1 Background

Spot welding (RSW) is a process in which contacting metal surfaces are

joined by the heat obtained from resistance to electric current flow. Work-pieces are

held together under pressure exerted by electrodes. Thickness of sheets range

typically is in the 0.5 to 3mm (0.020 to 0.12 in). Two shaped copper alloy electrodes

to concentrate welding current into a small “spot” and to simultaneously clamp the

sheets together used in the process. The metal will melt and form the weld if forcing

a large current through the spot. A lot of energy can be delivered to the spot in a

very short time (about ten milliseconds.) is the attractive feature of spot welding.

(Edward Smith et al, 2012)

The measure of heat (energy) delivered to the spot is determined by the

resistance between the electrodes and the amplitude and length time of current. To

match the sort of electrodes, sheet’s material properties, and its thickness, the

measure of energy is chosen. Metal won’t melt or will make a poor weld if applying

too little energy. Metal will melt too much if applying too much energy, eject molten

material, and make a hole instead of a weld. The energy delivered to the spot can be

controlled to deliver solid welds is another attractive feature of spot welding.

(Edward Smith, 2012)

2

Two cleaning method are use which is mechanical and chemical method.

Mechanical means such as wire brushing, shot blasting or grit blasting, grinding with

emery paper or cloth-(These are widely used. They are effective in removing oxide

layer, coatings and sand particles.)Chemical methods of cleaning include treatments

with acid (pickling), alkaline cleaning, and cleaning with organic solvents. The

common organic solvents for this purpose are kerosene, carbon tetrachloride (CC1₄ )

and trichloroethylene (C₂ HCI₃ ). These solvents dissolve oil, grease and paints.

1.2 Problem statement

Automotive industry uses resistance spot welding of it excellent joining

strength and quick process. Surface cracks, internal cracking and a bad appearance is

the physical effects of spot welding. The problems regarding in the spot welding are

surface integrity of the material surface has direct impact to the joining strength. The

main problem that must be solved is how to get the highest strength of spot welding

by using best cleaning methods.

1.3 Objective

1. To study on the surface cleaning method for best strength of spot welding.

2. To investigate the surface energy of cleaning surfaces using drop test.

3. To establish the correct cleaning process dealing with spot welding

3

1.4 Scope of the project

The work scope of this project is to study the surface cleaning method. This

focus area is done based on the few aspect which are only one material that is

aluminium material and 1mm thickness that will be use in this study. 10 sample of

each cleaning method before weld will be test by using drop test and 10 sample of

each cleaning method will undergo spot welding process which make it become 5

sample after welding(sample will be weld by perform lap joint using spot welding)

will test by using tensile test. This study can be divided into 3 cleaning methods

which are study cleaning method based on mechanical approach for example

cleaning with sand paper. There will be also using cleaning method based on

chemical approach which is organic solvents-turpentine and soap.

4

CHAPTER 2

LITERATURE RIVIEW

2.0 Introduction

The purpose of this literature is to discuss the related case studies associated

to the topic to help students in completing the objective. Books, journals, and

articles were used including the internet in order to understand everything about this.

In this chapter we will be going through the resistance spot welding, principle

cleaning method. Besides that we are going to discuss about material mild steel

sheet metal.

2.1 Welding

Welding is a sculptural process of joining two or more pieces of materials

either same or dissimilar to achieve complete coalescence. Usually this is achieved

by using heat and pressure. Today, welding is used widely for fabrication such as

pressure vessels and boilers, ships, bridges, railway coaches, pipeline, automobile

bodies, water turbines and press frames. This also includes fertiliser and chemical

plants. Classification of welding process is shown as figure 2.1 below.

5

Figure 2.1: Classification of Welding and Joining Processes

6

2.2 Resistance spot welding

One of the oldest welding processes in use in the industry is called resistance

welding. The combination of heat, pressure, and time produce the weld .The

resistance of the material to be welded to current flow that causes a localized heating

in the part is what implies the resistance welding. The tongs and electrode tips

produce pressure through which the current flows, holds the part to be welded tight,

during, after the welding current time cycle. The material thickness and type, the

amount of current flowing, and the cross-sectional area of the welding tip contact

surfaces will determined amount of time current flows in the joint. The Figure 2.2

below show how each parts of the resistance spot welding are determined.

(Miller,2012)

Figure 2.2: Resistance Spot Welding with work piece

2.3 Principle of the resistance spot welding

In order to accomplish the resistance welding, the current is caused to flow

through electrode tips and the separate pieces of metal to be put together. Weld is

formed by the localized heating in the joint which is caused by the resistance of the

base metal to electrical current flow. The actual weld nugget is formed internally in

relation to the surface of the base metal which makes the resistance spot weld unique

and different. The Figure 2.3 below shows a resistance spot welding.

7

Figure 2.3: Resistance Spot Welding

The resistance of the joint surfaces to electrical current flow will make the interface

of the weld joint heated thus producing the resistance spot weld nugget. It is

important thing to make sure the current must flow. During the making of the weld

the pressure of the electrode tips on the workpiece holds the part tight meaning in

close and intimate contact. Despite of that, the resistance spot welding machines are

not constructed as force clamps to pull the workpieces together for welding. (Miller,

2012)

Figure 2.4: Steps in making spot weld

There are a few steps in making spot weld as shown in Figure 2.4 above. The metal

is clamped between the electrodes under pressure in picture A. Picture B shows how

the process current flows. Weld nugget is formed in the picture C and picture D

display how the electrodes are removes after the weld become solid. (William A.

Bowditch, 2005)