of the requirements for the Bachelor ofEngineering (Hons) (Mechanical Engineering)

Defect Study ofPCBA at Manufacturing Company

by

Habibah Binti Harun 10308

Dissertation submitted in partial fulfillment of the requirements for the

Bachelor ofEngineering (Hons) (Mechanical Engineering)

MAY2011

Universiti Teknologi PETRONAS Bandar Seri Iskandar

31750 Tronoh

Perak Darul Ridzuan

Approved by,

CERTIFICATION OF APPROVAL

Defect Study ofPCBA at Manufacturing Company

by

Habibah Binti Harun

A project dissertation submitted to the Mechanical Engineering Programme

Universiti Teknologi PETRONAS In partial fulfillment of the requirement for the

BACHELOR OF ENGINEERING (Hons) (MECHANICAL ENGINEERING)

(Kam 'ff Zainal ^Abidi~- ..

UNIVERSITI TEKNOLOGI PETRONAS TRONOH PERAK

May 2011

CERTIFICATION OF ORIGINALITY

This is to certify that I am responsible for the work submitted in this project, that the original work is my own except as specified in the references and acknowledgements, and that the original work contained herein have not been undertaken or done by unspecified sources or persons.

ABSTRACT

This report basically presents the research that had been done so far based on this chosen topic, which is Defect Study ofPCBA at Manufacturing Company. A study of the defect has been undertaken as part of the design aod construction of a Knowledge-based System (KBS). The KBS will be required to contribute to a quality improvement in the maoufacture of Printed Circuit Board Assemblies (PCBA) aod in particular the defect level of the soldering process at maoufacturing facility. The defects that often occur during maoufacturing the PCBA is solder bridging. The project has involved the formal study of solder bridging during the maoufacture of highly complex aod sophisticated PCBA. The study methods used have included academic research, carefully designed experiments by Celestica engineers, observations of the maoufacturing processes aod interviews with a wide raoge of Celestica personnel. A process model has been developed to adopt a high level approach to the problem area aod as such embodies the ultimate goals of the proposed system. During the course of the project so far, in addition to the system process model development, part of the PCBA KBS has also been initiated.

ACKNOWLEDGEMENT

First and foremost, thank god for His grace and mercy that He gave to me, without it, maybe I cannot make it through until the end. I would like to extend my most sincere gratitude to the Manufacturing Engineer serve concurrently as my Supervisor, Mrs. Chew Y eat Kim for her full support with continuous encouragement and guidance for me towards completing this project. Besides that, I also want to thank her for monitoring my progress and for helping me to face any problem related to my project. Almost certainly without her cooperation, I might not be able to finish my project, as it needs a lot of commitment towards finishing it.

I would like to express my appreciation to all those who had assisted in making my Final Year Project a success. Especially I would like to thanks my UTP supervisor Mr.

Kamal Ariff Zainal Abidin whose help me a lot in completing this project. He was very supportive and assisted me all the time with guides and also advices.

Last but not least, many thanks go to all parties who had also contributed directly and indirectly to the success of my project. Thank you very much, may Allah repays for your kindness.

Thank you,

HABIBAH BINTI HARUN Mechanical Engineering

Universiti Teknologi PETRONAS

TABLE OF CONTENTS

CERTIFICATION . ¹

ABSTRACT. ¹¹

ACKNOWLEDGEMENT . 111

LIST OF FIGURES . IV

LISTOFTABLES . v

CHAPTER 1: INTRODUCTION

1

1.1 Background of Study .

1

1.2 Problem Statement

2

1.3 Objectives and Scope of Study

3

CHAPTER2: LITERATURE REVIEW

4

2.1

Introduction to Process Flow .

4

2.2

Wave Soldering Process 5

2.3

Preheating 7

2.4 Fluxing 8

2.5

^{Soldering 9}

CHAPTER3: METHODOLOGY . 11

3.1

Project Identification . 11

3.2

Understanding Assembly Process

12 3.2.1

Surface Mount Technology 13

3.2.2

Wave Soldering

14

3.2.3

Conformal Coating

15

3.2.4

Back End Process

15

3.3

Understanding Parameters of Wave Soldering

CHAPTER4:

CHAPTERS:

REFERENCES

APPENDICES

Machines

3.3.1 Temperature Solder 3.3.2 Flux

3.3.3 lntensity of Preheating

3.3.4 Arnonnt of Flux Deposited per nnit area 3.3.5 Conveyor Speed

3.5 Problem Solving Method

RESULT AND DISCUSSION 4.1 Problem Analysis 4.2 Data Analysis . 4.3 Observation

.

4.3.1 Component Leg is too long 4.3.2 Before Lead Prepping.

4.3.3 After Lead Prepping 4.4 Evaluation Result

CONCLUSION AND RECOMMENDATIONS 4.1 Conclusions .

4.2 Recommendations

16 16 19 19 20 20 21

24 24 25 26 26 26 27 29

32 32 32

34

35