Design And Fabrication Of Portable Spot Welding Machine

ABTRACT

This work is on fabrication of a low-cost spot-welding machine for students in higher institutions. The major factors controlling this process are current, time, electrode force, contact resistance, property of electrode material, sheet materials, surface condition etc. the quality is best judged by nugget size and joint strength. This study presents a systematic approach to determine effect of process parameters like electrode force, weld time and current. In this project, the effect of welding time on the tensile-shear strength and tensile-peel strength of the welding joints in electrical resistance spot welding of mild steel plates having 1.0 mm thicknesses were investigated. The plates are welded by electrical resistance spot welding by fixing electrode form, materials type and electrode force while changing welding current and time (second). The welding current was fixed at 4 kA. The electrode pressure was fixed at 6 kN while the welding time were changing at 2, 4, 6, 8, and 10 sec. The welding joints were exposed to tensile-shear and tensile-peel test and the effect of the welding time on tensile test were being investigated using related period diagram. The optimum welding times for tensile-shear test obtained at 4 sec and for the tensile-peel test also obtained at 4 sec.

COVER PAGE

1. CERTIFICATION

III. DEDICATION

1. ACKNOWLEDGEMENT
2. ABSTRACT:

CHAPTER ONE

1.0    INTRODUCTION

1.1    Background of the study

1.2    Statement of the problem

1.3    Aim and objectives of study

1.4    Advantages of the project

1.5    Scope of the project

1.5    Applications of spot welding

CHAPTER TWO

LITERATURE REVIEW

2.1 Overview of a spot welding

2.2   Review of related studies

2.3    Spot welding of process and equipment

2.4    Spot welding characteristics

2.5    Application of spot welding machine

CHAPTER THREE

METHOD

3.1    MATERIALS AND METHODOLOGY

3.2    MATERIALS OF SPOT WELDING

3.3    FABRICATION

CHAPTER FOUR

RESULTS/ANALYSIS

4.1 Construction procedure and testing analysis

4.2   Assembling of sections

4.3   Testing of system operation

4.4   Analysis

CHAPTER FIVE

Conclusion

References

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

Spot welding is one of the oldest of the electric welding processes in use by industry today. The weld is made by a combination of heat, pressure and time. As the name resistance welding implies, it is the resistance of the material to welded, to current flow that causes a localized heating in the part. The pressure exerted by the tongs and electrode tips, through which the current flows, holds the parts to be welded in intimate contact before, during and after the welding current time cycle. The required amount of time current flows in the joints is determined by material thickness and types, the amount of the current flowing and the cross-sectional are of the welding tip contact surface. Resistance spot welding is accomplished when current is caused to flow through the electrode tips and the separate pieces of mental to be joined. The resistance of the base metal to electric current flow causes localized heating in the joint and the weld is made. The resistance spot weld nugget is unique because the actual weld nugget is formed internally with relation to the surface of the base metal.

1.2                                                  PROBLEM STATEMENT

Conventional spot welding machine requires a lot of space, is heavy, restricted by height and does not weld at any angle. In this project, we have tried to overcome the above problems by recreating the design. We made it a simpler, lighter, portable, compact and flexible machine which will be able to weld at any angle and can be easily operated by even a non-skilled Labor with much ease and required accuracy.

1.3                                  AIM AND OBJECTIVES OF THE PROJECT

The main aim of work is to develop low-cost spot-welding machine for students in higher institutions. The objectives of the study are:

1. To build a portable spot welding machine for academic
2. To study the working principle and analysis of a spot welding machine

• To determine effect of process parameters like electrode force, weld time and current.

1.4                                          ADVANTAGES OF THE PROJECT

This machine is simple, light, portable, compact and flexible machine which will be able to weld at any angle and can be easily operated by even a non-skilled Labor with much ease and required accuracy.

1.5                                                 SCOPE OF THE PROJECT

This scope of this work is the fabrication of the portable spot-welding machine which is divided into two phases, first is the formation of basic circuit of machine which includes small transformer of 1.2 kVA with output voltage 0 to 2.2 volt with 2.5-gauge wire and power switch and second is the formation of body and arm mechanism of the machine. For creating this machine, we used modeling software such as Autodesk Fusion 360 and created a prototype based on its design. In this project we made our own transformer according to requirements of specifications for welding as a general transformer used in electronic appliances.

     1.6                                    APPLICATIONS OF SPOT WELDING

Some of the applications of spot welding are given as follows:

• Spot welding is used in various industries such as automotive, aerospace, metal furniture, electronics, building construction, etc.
• Spot welding is used in high volume production applications.
• It is applied for welding of thin sheets.
• Spot welding is also used for fabricating all types of sheet metal structures where high mechanical strength is required.
• Spot welding can also be applied to all types of boxes, cores and enclosing cases, etc.