quality-improvement-by-using-sigma-concepts-in-injection-moulding-manufacturing.pdf

7/27/2019 quality-improvement-by-using-sigma-concepts-in-injection-moulding-manufacturing.pdf

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PERSONAL DETAIL

Name : Suresh s/o Vasu

IC No. : 830811-05-5287

Date of Birth : 11th

August 1983

Age : 24

Sex : Male

Nationality : Malaysian

Contact Address : 290 Taman Temiang Jaya, Jalan Sikamat,

70400 Seremban, Negeri Sembilan D.K.

Tel. No.(H/P) : 017-3118109

Tel. No. (Home) : 06-7634612

E-mail :[email protected]


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QUALITY IMPROVEMENT USING SIX SIGMA

CONCEPTS IN INJECTION MOULDINGMANUFACTURING

SURESH A/L VASU

UNIVERSITI TEKNIKAL MALAYSIA MELAKA


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UNIVERSITI TEKNIKAL MALAYSIA, MELAKA

QUALITY IMPROVEMENT USING SIX SIGMA

CONCEPTS IN INJECTION MOULDINGMANUFACTURING

Thesis submitted in accordance of with the requirement of the Universiti Teknikal

Malaysia Melaka for the Degree of Bachelor of Engineering (Honours)

Manufacturing (Manufacturing Process)

By

SURESH S/O VASU

B050510019

Faculty of Manufacturing EngineeringApril 2008


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ABSTRACT

This thesis has focused on the quality improvement of major defect injection

moulding assembly line in the XXX Sdn.Bhd. The objectives of this thesis were to

identify current quality problem and to improve major quality problem in the 30 tone

injection moulding operation department using Six-Sigma DMAIC methodology. In

order to analyze the data some of Statistical Quality Control (SQC) tools were used

such as pareto chart, histogram, cause and effect diagram and control chart. The main

defects in the assembly line determined and proper tool is used to analyze the quality

problem. Major defects were highlighted and analyzed. Root causes for the problems

were determined and suggestions for improvement were suggested. After the

improvement stage, suggestions for control the quality also were suggested.


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ABSTRAK

Tesis ini bertujuan untuk memperbaiki kualiti pada produk yang di hasilkan melaui

proses injection moulding di XXX Sdn.Bhd. Objektif tesis ini adalah, untuk

mengenalpasti masalah kualiti yang dihadapi pada masa kini di kawasan kajian dan

seterusnyamemperbaiki masalah tersebut dengan menggunakan metodologi enam-

sigma(DMAIC). Untuk menganalisa data yang diperbaiki, beberapa komponen-

komponen kawalan kualiti secara statistik (SQC) seperti rajah pareto, histogram,

rajah sebeb dan akibat dan rajah kawalan. Masalah-masalah kualiti yang wujud pada

produk yang dihasilkan dikesan. Daripada masalah-masalah ini masalah utama akan

dikenalpasti dan dianalisis. Sebab-sebab utama masalah tersebut berlaku dan

cadangan untuk memperbaiki masalah tersebut akan dicadangkan. Selepas itu,

cadangan untuk mengawal kualiti pada produk siap juga akan dicadangkan.


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DEDICATION

This thesis is dedicated to my parents, aunty, brother, sisters and other family

members who provide a loving, caring, encouraging and supportive atmosphere.

These are characteristics that contribute to the environment that is always needed to

achieve the goals ahead.


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ACKNOWLEDGEMENTS

Many people have contributed to my learning experience at the Universiti Teknikal

Malaysia, Melaka. I would like to thank for my thesis advisor MR. HAERY

SIHOMBING and co- advisor PN.ROHANA, for his and her insight, thought

provoking questions and guidance for my thesis.

I also would like to thank MR.SIVA who is a senior engineer in XXX Malaysia for

his contribution for this thesis. He has spent his valuable time to guide me to gather

some information for this thesis. I also would like to thank other XXX staffs who

contribute directly or indirectly in this thesis.

Finally, I would like to thank my family members and friends who provide a loving,

caring, encouraging and supportive atmosphere.


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TABLE OF CONTENTS

Declaration .....i

Approval...ii

Abstract...iii

Abstrak........iv

Dedication .....v

Acknowledgement ........vi

Table of Contents .....vii

List of Figures ........ xi

List of Tables ...xiii

List of List Of Abbreviations, Symbols, Specialized Nomenclature ..xiv

1. INTRODUCTION.......1

1.1 Background ......1

1.2 Problem Statements.......4

1.3 Objectives of the Research........4

1.4 Scope Of Project........4

1.5 Project Overview.......5

2. LITERATURES REVIEW.............6

2.1 Introductions .........6

2.2 Definitions of quality..6

2.3 Quality Management Philosophies ....7

2.3.1 The Deming Philosophy .8

2.3.1.1 Deming's 14 Points for Management .......9

2.3.2 Jurans Quality Trilogy...10

2.3.3 The Crosby philosophy ......11


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2.4 Introduction and Implementation of Total Quality Management (TQM).....12

2.4.1 TQM Defined.........12

2.4.2 Implementation Principles and Processes of TQM..13

2.4.3 Summary for TQM.14

2.5Six-Sigma Quality......15

2.5.1 Six-Sigma methodology16

2.5.1.1 Define (D)....17

2.5.1.2 Measure (M)..........18

2.5.1.3 Analyze (A) ......19

2.5.1.4 Improve (I) ....20

2.5.1.5 Control (C) ..21

2.6Analytical tools for Six-Sigma and continuous improvement.232.7Six-Sigma versus Total Quality Management (TQM) ...29

2.8Six-Sigma versus Other Quality system or tools........31

2.8.1 ISO 9001 objectives......31

2.8.1.1 Comparison of ISO 9001 with Six Sigma......31

2.8.1.2 Combining Six Sigma with ISO............31

2.8.2 Lean manufacturing objectives....32

2.8.2.1 Comparison with Six Sigma......33

2.8.2.2 Combining Lean Manufacturing with Six Sigma....34

2.8.3 Comparison between six sigma DMAIC and PDCA..35

2.9Case study: An example of DMAIC at American Express35

2.9.1 The general situation.....36

2.9.2 Define and Measure......36

2.9.3 Analyze.........36

2.9.4 Improve........37

2.9.5 Control......37

2.10 Summary .........37

3.METHODOLOGY.......39

3.1Introduction.........39

3.2Company selection......39


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3.3 Methodology.......39

3.3.1 Define stage. ......41

3.3.2 Measure stage....41

3.3.3 Analyze stage.......42

3.3.4 Improve stage.......42

3.3.5 Control stage.....42

3.4Techniques used in identifying the general and major problem.....43

3.4.1 Interview.........43

3.4.2 Observation....43

3.4.3 Data Collection.......43

3.5Gantt chart ......44

3.6 Summary ........45

4. COMPANY BACKGROUND...46

4.1 Introduction.......46

4.2 Companies Profile.......46

4.3 Companies Location....48

4.4Companys Product...49

4.5 Introduction To Injection Moulding ..50

4.5.1 Injection Molding Cycle & Process...52

4.5.2 Moulding Defects. 54

5. RESULT AND DISCUSSION.....56

5.1 Introductions ...56

5.2 DMAIC Define stage56

5.2.1 Define the process.56

5.2.2 Molding Process Flow Chart.58

5.2.3 Identify the current reject problem59

5.3 DMAIC- Measure stage..60

5.4 DMAIC- Analyze stage63

5.4.1 Potential causes for high defects occurred in part BMQ case A65

5.4.2 Root causes analysis....66


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5.4.2.1 Root causes analysis for Black dot defect66

5.4.3 Summary on the analysis68

5.5 DMAIC- Improve stage69

5.5.1 Introduction69

5.5.2 Screw and barrel cleaning69

5.5.2.1 Screw cleaning.69

5.5.2.2 Barrel cleaning.70

5.5.3 PP and special material for cleaning screw and barrel by purging72

5.5.3.1 Characteristic of cleaning agents72

5.5.3.2 Comparison between the cleaning agents73

5.5.3.3 Result after implementation of both cleaning agents76

5.5.4 Summary on improve stage815.6 DMAIC- Control stage81

5.6.1 Control chart.81

5.6.1.1 Suggested steps in constructing a c-chart81

5.7Summary 83

6. CONCLUSION84

6.1 Conclusion..84

6.2 Suggestion for further study84

REFERENCES...86

APPENDICES

A List of rejection or part from month JAN to MAC 2007

B List of rejection type for month May to Oct 2007

C Overall calculation for sigma level


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LIST OF FIGURES

2.1 SIPOC analysis diagram for Define stage 23

2.2 Measurement stage 25

2.3 Cause and Effect diagram for analyze stage 26

2.4 Opportunity flow diagram for Improve stage 27

2.5 Control chart for Control stage 28

3.1 Methodology flow chart 40

4.1 The graphic above shows the Nilai Plant layout 47

4.2 Plant location 48

4.3 Remote controllers 49

4.4 Sumitomo injection moulding machine 51

5.1 The Cover molding process 58

5.2 In- line rejection 60

5.3 In-line reject from month May to October 2007 62

5.4 Sigma level from month May to October 2007 63

5.5 Reject data based on the defect type for month May 2007 64

5.6 Potential causes for high defects 66

5.7 Root causes analysis for Black dot Injection screw before cleaning 68

5.8 Injection screw before cleaning 69

5.9 Injection screw after cleaning 70

5.10 Barrel before cleaning 70

5.11 Barrel after cleaning 71

5.12 Machine covered with plastic 71

5.13 Black Dot trend before and after screw cleaning for machine E03 72


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5.14 Cleaning Agent 1 (PP) 73

5.15 Cleaning Agent 2 (Special material) 74

5.16 Purging process of Agent 1 (PP) 74

5.17 Purging process for Agent 2 (special material) 75

5.18 Black dot trend before and after special material cleaning 76


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LIST OF TABLES

2.1 TQM VS Six-Sigma 30

2.2 Comparison between DMAIC and PDCA (Donna C.S summers, 2003) 35

3.1 Gantt chart 44

4.1 Injection moulding cycle 53

4.2 Common moulding defects 54

5.1 In- line rejection based on part produced 59

5.2 Total output and Sigma level 61

5.3 Reject data based on the defect type for month May 2007 64

5.4 Comparison with Special Cleaning material and Current use Material (PP) 75

5.5 Cost calculation for the material price and amount 77

5.6 Cost calculation for down time and labor cost 78

5.7 Cost calculation for Scrap data 79

5.8 Cost calculation for Scrap data 80


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LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZEDNOMENCLATURE

ANOVA - Analysis of Variance

CTQ - Critical to Quality

DMAIC - Define, Measure, Analyze, Improve, Control

DOE - Design of experiment

DPMO - Defect per Million Opportunities

FMEA - Failure Mode and Effect Analysis

KPOV - Key Process Output Variables

KPIV - Key Process input Variables

PDCA - Plan, Do, Check, Act

SIPOC - Supplier, Inputs, Process, Outputs, Customers

SPC - Statistical Process Control

TQM - Total Quality Management

SQC - Statistical Quality Control


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CHAPTER 1

INTRODUCTION

1.1 Project Background

Quality has become one of the most important competitive strategic tools which

many organizations have realized it as a key to develop products and services in

supporting continuing success. Quality system is designed to set a clear view for

organization to follow enabling understanding and involvement of employees

proceeding towards common goal.

The aim of business is long term profitability. Over a considerable length of time,

earning is achieved by pleasing customers with good products or services while

keeping production cost at a minimum. The use of quality tools and technique

provides long term dividends through lower costs and productivity improvements.

As competition increases and changes occur in the business world, one should need

to have a better understanding of quality. Quality concerns affect the entire

organization in every competitive environment. Consumer demands high qualitylevel of product or services at reasonable prices to achieve value and customers

satisfaction.

There is an increasing focus on quality throughout the world. With increased

competition, companies have recognized the importance of quality system


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implementation in maintaining effectiveness in a volatile business environment.

Specifically meeting the needs and desired of the customers is critical and must be

done much better and efficiently than it has done in the past.

Total Quality Management (TQM) is one of the most common quality management

practices in todays industrial environment. TQM refer to the broad set of

management and control processes designed to focus an entire organization and all of

its employees on providing products or services that do the best possible job of

satisfying the customer. According to Sashkin and Kiser (1993), TQM means that the

organizations culture is defined by, supports, the constant attainment of customer

satisfaction through an integrated system of tools, techniques, and training. This

involves the continuous improvement of organizational process, resulting in high

quality products and services.

Thus, the TQM philosophy of management is customer-focused. TQM incorporates

the concepts of product quality, process control, quality assurance, and quality

improvement. Some advise that customer satisfaction is the driving force behind

quality improvement; other suggest quality management is achieved by internal

productivity or cost improvement programs; and still others consider TQM as mean

to introduce participatory management. In general, the Japanese concentrate on

customer satisfaction with a particular focus on understanding customer needs and

expectations.

Besides TQM there are other quality system used to improve quality such as Lean

and Six Sigma. These two are related, but distinct. Among the several quality

management concepts that have been developed, the lean concept, as in lean

manufacturing, lean production, etc. is one of the more wide-spread and successful

attempts. Briefly, lean is about controlling the resources in accordance with the

customers needs and to reduce unnecessary waste (including the waste of time). The

concept was introduced at a larger scale by Toyota in the 1950s, but not labeled lean

manufacturing until the now famous book about the automobile appeared in 1990

(Womack et al., 1990). While there are many formal definitions of the lean concept,

it is generally understood to represent a systematic approach to identifying and


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eliminating elements not adding value to the process. Consequences of this are

striving for perfection and a customer-driven pull of the process.

Meanwhile, most recent quality philosophy to be adopted by businesses around the

world is known as Six Sigma. The founder of the Six Sigma philosophy is Mikel

Harry (Harry and Schroeder, 2000). Mikel Harry developed and implemented his

Six Sigma philosophy with the Motorola Corporation and the philosophy has had

great success at the GE Corporation (Harry and Schroeder, 2000). Six sigma focuses

on the reduction and removal of variation by the application of an extensive set of

statistical tools and supporting software. This powerful business management

strategy has been exploited by many world class organizations such as General

Electric (GE), Motorola, Honeywell, Bombardier, ABB, Sony, to name a few fromthe long list. Six sigma applications in the service sector are still limited although it

has been embraced by many big service oriented companies such as J P Morgan,

American Express, Lloyds TSB, Egg, City Bank, Zurich Financial Services, BT, etc.

Six sigma today has evolved from merely a measurement of quality to an overall

business improvement strategy for a large number of companies around the world.

The concept of six sigma was introduced by Bill Smith in 1986, a senior engineer

and scientist within Motorolas communication Division, in response to problems

associated with high warranty claims. The success of the efforts at Motorola was not

just achieving six sigma quality level rather the focus was on reducing defect rate in

processes through the effective utilization of powerful and practical statistical tools

and techniques. This would lead to improved productivity, improved customer

satisfaction, enhanced quality of service, reduced cost of operations or costs of poor

quality, and so on.

This thesis mainly focused on six sigma quality philosophy and other related

philosophy that would be implemented in these studies in order to identify the

current problem or rejection criteria facing by the company. The Six Sigma

philosophy used because, it provides a step-by-step quality improvement

methodology that uses statistical methods to quantify variation. An extensive on


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related literature reviews was carried in order to enhance more knowledge on the

related study field.

1.2 Problem Statement

Currently in XXX Electric Parts Production Department which produce Plastic

product for Electronic Component especially Remote Control as main business

facing many rejection problem. The main defect cause this rejection is Black dot

on the appearance of the product. There are also some other causes that lead to

rejection such as part breakage, scratches, oily surface, white mark silver mark,

parting burr and etc. In order to study the problem a research has carried out with

help of an engineer by study the literature review on TQM, Six Sigma and PDCA

philosophies and other reference for this analysis and research method.

1.3 Objectives

The objectives of this thesis are:

To utilize six sigma methodology in performing the study.

To study the black dot rejects utilizing QC tools at the identified assembly

lines.

To identify the root causes of the black dotrejects

To recommend actions to improve the black dot rejects and sigma level.

1.4 Scope Of Project

The scope of the study is limited to part production 30 tone assembly lines only and

the analysis is focused on major defect only. Six Sigma DMAIC methodologies will

be used where DMA is applied and IC will be suggested to the company. The data

will be collected for the assembly line for six month period from May 07 to October

07.


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1.5 Report outline

Chapter 1 gives an introduction to the projects which are including objectives, scope,

and background. In this chapter, it describes the background of quality problem as

the case study of Company.

Chapter 2 presents the literature review on concepts of TQM, Six-Sigma Quality, and

what the correlation about DMAIC with other Quality Improvement approaches

(PDCA). It also presents some quality tools that incorporate with the study.

Chapter 3 describes the company background and the description of the methodology

used in this project.

Chapter 4 presents the data analysis using Six-Sigma methodology. In this chapter

the collected data from the case Study Company was analyzed stage by stage. First,

the analysis starts with Define stage, which is continued with Measurement stage and

then followed by Analyze stage. After analyze the problem based on the data

collected, and then we go to the Improve stage and culminate with Control stage.

Chapter 5 presents the conclusions of the whole project and suggestions for future

work.


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CHAPTER 2LITERATURE REVIEW

2.1 Introduction

Literature review includes study and research of published materials like journals,

thesis, case studies, technical documents and online library. Generally, the purpose of

a review is to analyze critically a segment of a published body of knowledge through

summary, classification and comparison of prior research studies, reviews of

literature, and theoretical articles. This chapter will describe topics that related to

quality such as Total Quality Management, Quality Management Philosophies, Six-

Sigma methodology, ISO 9000, Lean manufacturing, concept of quality, quality tools

and other relevant quality topics. Emphasizes is more on six sigma methodology

since the study conducted in a Six Sigma manner.

Besides that, this chapter also includes review on injection moulding process which

currently applied by the studied company and the types of defects that frequently

occurs in the production line.

2.2 Definitions of quality

In the Websters New World Dictionary, quality is defined as physical or

nonphysical characteristic that constitutes the basic nature of a thing or is one of its

distinguishing features.


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Shewhart (1980), mention that there are two common aspects of quality; one of these

has to do with the consideration of the quality of a thing as an objective reality

independent of the existing of man. The other has to do with what we think, feel or

sense as a result of the objective reality. This subjective side of quality is closely

linked to value. It is convenient to think of all matters related to quality of

manufactured product in terms of these three functions of specification, production

and inspection. (Grant and Leavenworth, 1988).

Quality is fitness for use, (Juran, 1989). Quality is conformance to requirements

(Crosby, 1986) and quality should be armed at the needs of the customer present and

future (Deming, 1986).

Feigenbaum (1983) said that quality is the total composite product and service

characteristics of marketing, engineering, manufacture and maintenance through

which he product and service in use will meet the expectations of the customer.

Mizuno (1988) mention that product quality encompasses those characteristics which

the product most posses if it is to be used in the intended manner. Actually, quality

can take many forms. All the definitions mentioned above can be classified into three

types. They are quality of design, quality of conformance and quality of

performance. Quality of design means that the product has been designed to

successfully fill a consumer need, real or perceived. Quality of conformance refers to

the manufacture of the product or the provision of the service that meets the specific

requirements that set by customer. Finally, quality of performance brings out the

definitions that the product or service performance its intended function as identified

by the customer.

2.3 Quality Management Philosophies

More managers than ever before are focusing on quality as a way of increasing

productivity, reducing costs, and meeting customer needs. These managers are


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beginning to understand the importance of continuously improving the quality of

their services and products as a means of achieving these goals. Those who begin to

learn about quality quickly become familiar with the names of Philip B. Crosby,

W.Edwards Deming, and Joseph M. Juran--renowned quality experts--who have

been carrying forth the message of quality for more than 30 years. At an age when

most people have retired, Philip B. Crosby and Joseph M. Juran continue an untiring

pace of work conducting seminars, consulting with clients, and writing new texts.

They have devoted their lives to helping organizations improve the quality of their

products and services. Their influence is now worldwide and their accomplishments

are legendary in the discipline.

2.3.1 The Deming Philosophy

W. Edwards Deming was originally trained as a statistician, and much of his

philosophy can be traced to these roots. He worked for Western Electric during its

pioneering era of statistical quality control development in the 1920s and 1930s.

During World War II, he taught quality control courses as part of the national

defense effort. Deming began teaching statistical quality control in Japan shortly

after Word War II a is credited with having been an important contributor to the

Japanese quality improvement programs. In fact, the highest award for quality

improvement in Japan is called the Deming Prize. While Japan embraced his

methods for 30 years, he was virtually unknown in the United States until 1980.

Deming focuses on the improvement of product and service conformance to

specifications by reducing uncertainty and variability in the design and

manufacturing process. In Deming's view, variation is the chief culprit of poor

quality. In mechanical assemblies, for example, variations from specifications for

part dimensions lead to inconsistent performance and premature wear and failure.

Likewise, inconsistencies in service frustrate customers and hurt the reputation of the

company. To achieve reduction of variation refines a never-ending cycle of product

design, manufacture, test, and sales, followed by market surveys, then redesign, and


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so forth. Deming claims that higher quality leads to higher productivity, which in

turn leads to long-term competitive advantage. The Deming "chain reaction" theory

summarizes this view; the theory states that process improvements lead to lower

costs due to less rework, fewer mistakes, delays and snags, and more efficient use of

materials. Lower costs, in turn, lead to productivity improvements. With better

quality and lower prices, the firm can achieve a greater or larger market share and

remain competitive and provide more meaningful and rewarding jobs. Upper

management needs to recognize the benefits of quality as a strategic factor and strive

to create a culture that supports empowerment, continuous improvement and

customer satisfactions. Deming stresses that top management has the overriding

responsibility for quality improvement (Deming, 1986)

2.3.1.1 Deming's 14 Points for Management

1. Create and publish to all employees a statement of the aims and

purposes of the company or other organization. Management must

demonstrate constantly their commitment to this statement

2. Learn the new philosophy throughout all areas everybody.

3. Understand the purpose of inspection. It should evaluate process

improvements and cost reductions.

4. End the practice of awarding business on the basis of price alone

5. Improve constantly and forever the system of production and service

6. Institute training

7. Teach and institute leadership

8. Drive out fear. Create trust. Create a climate for innovation

9. Optimize all efforts toward the aims and purposes of the company.

10. Eliminate exhortations for the work force

11. (a) Eliminate numerical quotas for production Instead learn and institute

methods for improvement

(b) Eliminate management by objectives (MBO). Instead, learn the

capabilities of processes, and how to improve them.


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12. Remove barriers that rob people of pride of workmanship.

13. Encourage education and self-improvement for everyone.

14. Take action to accomplish the transformation

2.3.2 Jurans Quality Trilogy

Dr. J. M. Juran, whose impact on the quality movement in Japan, was second only to

Demings, developed a useful framework to what referred to as "a universal thought

process-a universal way of thinking about quality, which fits all functions all levels,

all product lines. He called it the "quality trilogy: The underlying concept of the

quality trilogy is that managing for quality consists of three basic quality orientedprocesses:

Quality planning

Quality control

Quality improvement

The starting point is quality planning which involves creating a process that will be

able to established goals. Once the process is turned over to the operating forces,

their responsibility is to run the process at optimal effectiveness and take corrective

action when the process or product does not conform to established specifications.

Finally, quality improvement is "the process for breaking through to unprecedented

levels of performance. But quality improvement does not happen of its own accord.

It results from purposeful action taken by upper management to introduce a new

managerial approach throughout the organization of quality improvement process.

This quality improvement process is super-imposed on the quality control process. It

is implemented in addition to quality control, not instead of it. Juran's approach is

essentially the same as Demings. Quality is a management responsibility that needs

to be performed systematically to achieve continuous improvement over time.


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This is the same basic idea behind the so-called PDCA cycle, known in Japan as the

Deming wheel, which is considered to be the essence of the Japanese approach to

total quality control:

Plan: The basic planning process described by Juran.

Do: The implementation of the plan.

Check: Evaluation of performance according to critical measures appropriate

methods

Act: Quality improvement efforts based on the lessons learned from

experiences. These experiences feed into the new plan, since PDCA is a

cyclical process (Costin, 1994)

2.3.3 The Crosby philosophy

Philip B. Crosby was corporate vice president for quality at International Telephone

and Telegraph (ITT) for 14 years after working his way up from line inspector. After

that he e established Philip Crosby Associates in 1979 to develop and offer training

programs related to quality. He is also the author of several popular books. His first

book, Quality is Free published in 1979, sold about one million copies.

The essence of Crosby's quality philosophy is embodied in what he calls the

"Absolutes of' Quality Management and the Basic Elements of Improvement."

Crosby's Absolutes of Quality Management areas follow:

Quality means conformance to requirement, not elegance

There is no such thing as quality problem only opportunities to improve.

There is no such thing as the economics of quality; it always cheaper to

do the job right the first time.

The only performance measurement is the cost of quality approach.

The only performance standard is Zero Defect


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Crosby's Basic Elements of Improvement include determination, education, and

implementation. By determination, Crosby means that top management must be

serious about quality improvement. The Absolutes should be understood by

everyone; this can be accomplished only through education. Finally, every member

of the management team must understand the implementation process. (Evans &

Lindsay,1993).

2.4 Introduction and Implementation of Total Quality Management

(TQM)

Total Quality Management is a management approach that originated in the 1950's

and has steadily become more popular since the early 1980's. Total Quality is a

description of the culture, attitude and organization of a company that strives to

provide customers with products and services that satisfy their needs. The culture

requires quality in all aspects of the company's operations, with processes being done

right the first time and defects and waste eradicated from operations.

Total Quality Management, TQM, is a method by which management and employees

can become involved in the continuous improvement of the production of goods and

services. It is a combination of quality and management tools aimed at increasing

business and reducing losses due to wasteful practices. Some of the companies who

have implemented TQM include Ford Motor Company, Phillips Semiconductor,

SGL Carbon, Motorola and Toyota Motor Company (Gilbert, 1992).

2.4.1 TQM Definination

TQM is a management philosophy that seeks to integrate all organizational functions

such as marketing, finance, design, engineering, and production, customer service,

etc. to focus on meeting customer needs and organizational objectives.


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TQM views an organization as a collection of processes. It maintains that

organizations must strive to continuously improve these processes by incorporating

the knowledge and experiences of workers. The simple objective of TQM is "Do the

right things, right the first time, every time". TQM is infinitely variable and

adaptable.

Although originally applied to manufacturing operations, and for a number of years

only used in that area, TQM is now becoming recognized as a generic management

tool, just as applicable in service and public sector organizations. There are a number

of evolutionary strands, with different sectors creating their own versions from the

common ancestor.

TQM is the foundation for activities, which include commitment by senior

management and all employees, meeting customer requirements, reducing

development cycle times, Just In Time/ Demand flow manufacturing and

improvement teams. This shows that all personnel, in Manufacturing, Marketing,

Engineering, R&D, Sales, Purchasing, HR, etc must practice TQM in all activities.

(Hyde,1992).

2.4.2 Implementation Principles and Processes of TQM

A preliminary step in TQM implementation is to assess the organization's current

conditions. Relevant preconditions have to do with the organization's history, its

current needs, precipitating events leading to TQM, and the existing employee

quality of working life. If the current reality does not include important

preconditions, TQM implementation should be delayed until the organization is in a

state in which TQM is likely to succeed.

If an organization has a track record of effective responsiveness to the environment,

and if it has been able to successfully change the way it operates when needed, TQM

will be easier to implement. If an organization has been historically reactive and has


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little skill at improving its operating systems, there will be both employee skepticism

and a lack of skilled change agents. If this condition prevails, a comprehensive

program of management and leadership development may be instituted. A

management audit is a good assessment tool to identify current levels of

organizational functioning and areas in need of change. An organization should be

basically healthy before beginning TQM. If it has significant problems such as a very

unstable funding base, weak administrative systems, lack of managerial skill, or poor

employee morale, TQM would not be appropriate (Tichey, 1993).

However, a certain level of stress is probably desirable to initiate TQM. People need

to feel a need for a change. Kanter (1983) addresses this phenomenon as building

blocks, which are present in effective organizational change. These forces includedepartures from tradition, a crisis or galvanizing event, strategic decisions, individual

"prime movers," and action vehicles. Departures from tradition are activities, usually

at lower levels of the organization, which occur when entrepreneurs move outside the

normal ways of operating to solve a problem. A crisis, if it is not too disabling, can

also help create a sense of urgency, which can mobilize people to act. In the case of

TQM, this may be a funding cut or threat, or demands from consumers or other

stakeholders for improved quality of service. After a crisis, a leader may intervene

strategically by articulating a new vision of the future to help the organization deal

with it. A plan to implement TQM may be such a strategic decision. Such a leader

may then become a prime mover, who takes charge in championing the new idea and

showing others how it will help them get where they want to go. Finally, action

vehicles are needed and mechanisms or structures to enable the change to occur and

become institutionalized (Smith, 1999).

2.4.3 Summary for TQM

TQM encourages participation amongst shop floor workers and managers. There is

no single theoretical formalization of total quality, but Deming, Juran and Ishikawa

provide the core assumptions, as a:


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"...discipline and philosophy of management which institutionalizes planned and

continuous improvement ... and assumes that quality is the outcome of all activities

that take place within an organization; that all functions and all employees have to

participate in the improvement process; that organizations need both quality systems

and a quality culture."

2.5 Six-Sigma Quality

Six-Sigma refers to the philosophy and methods companies such as General Electric

and Motorola use to eliminate defects in their products and processes. A defect is

simply any component that does not fall within the customers specification limits.

Each step or activity in a company represents an opportunity for defects to occur and

Six-Sigma programs seek to reduce the variation in the processes that lead to these

defects. Indeed, Six-Sigma advocates see variation as the enemy of quality and much

of the theory underlying Six-Sigma is devoted to dealing with this problem. A

process that is in Six-Sigma control will produce no more than 3.4 defects out of

every million units.

One of the benefits of Six-Sigma thinking is that it allows managers to readily

describe the performance of a process in terms of its variability and to compare

different processes using a common metric. This metric is defects per million

opportunities (DPMO). (Raisinghani,M.S 2005).This calculation requires three

pieces of data:

Unit: The item produced or being serviced.

Defect: Any item or event that does not meet the customers

requirements.

Opportunity: A chance for a defect to occur.

A straightforward calculation is made using the following formula:


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2.5.1 Six-Sigma methodology

Six Sigmas methods include many of the statistical tools that were employed in

other quality movements, Six-Sigma is employed in a systematic project-oriented

fashion through define, measure, analyze, improve, and control (DMAIC) cycle. The

DMAIC cycle is a more detailed version of the Deming PDCA cycles, which

consists of four steps Plan, Do, Check, and Act within continuous improvement.

Continuous improvement, also called Kaizen, seeks continual improvement of

machinery, materials, labor utilization, and production methods through application

of suggestions and ideas of company teams. Like Six Sigma, it also emphasizes the

scientific method, particularly hypothesis testing about the relationship between

process inputs (Xs) and outputs (Ys) using design of experiments (DOE) methods.

The availability of modern statistical software has reduced the drudgery of analyzing

and displaying data and is now part of the Six-Sigma tool kit. The overarching focus

of the methodology, however is, understanding and achieving what the customer

wants, since that is seen as the key to profitability of a production process. In fact, to

get across this point, some use the DMAIC as an acronym for Dumb Managers

Always Ignore Customers.

The standard approach to Six-Sigma projects is the DMAIC methodology developed

by General Electric (G.E). The DMAIC methodology is central to Six Sigma process

improvement projects. The following phases provide a problem-solving process in

which specific tools are employed to turn a practical problem into a statisticalproblem, generate a statistical solution and then convert that back into a practical

solution (Henderson, Evans and et al, 2000).

DPMO = Number of defects

Number of opportunities for error per unit x Number of unit

X 1,000,000


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2.5.1.1 Define (D)

The purpose of the Define phase is to clearly identify the problem, the requirements

of the project and the objectives of the project. The objectives of the project should

focus on critical issues, which are aligned with the companys business strategy and

the customers requirements. The Define phase includes:

Define customer requirements as they relate to this project. Explicit customer

requirements are called Critical-to-Quality (CTQ) characteristics;

Develop defect definitions as precisely as possible;

Perform a baseline study (a general measure of the level of performance

before the improvement project commences);

Create a team charter and Champion;

Estimate the financial impact of the problem; and

Obtain senior management approval of the project

Some of the key questions addressed in this stage are:

What matters to the customers?

What Defect are we trying to reduce?

By how much and by when?

What is the current Cost of defects?

Who will be in the project team?

Who will support us to implement this project?

The most applicable tools in this phase are the following:

Project Charter - this document is intended to clearly describe the

problem, defects definitions, team information and deliverables for a

proposed project and to obtain agreement from key stakeholders.

Trend Chart - to see (visually) the trend of defect occurrence over a

period of time.

Pareto Chart - to see (visually) how critical each input is in contributing

negatively or positively to total output or defects.

Process Flow Chart - to understand how the current processes functions

and the flow of steps in current process


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2.5.1.2 Measure (M)

The purpose of the Measure phase is to fully understand the current performance by

identifying how to best measure current performance and to start measuring it. The

measurements used should be useful and relevant to identifying and measuring the

source of variation. This phase includes:

Identifying the specific performance requirements of relevant Critical-to-

Quality

(CTQ) characteristics;

Map relevant processes with identified Inputs and Outputs so that at each

process step, the relevant Outputs and all the potential Inputs (X) that might

impact each Output are connected to each other;

Generate list of potential measurements

Analyze measurement system capability and establish process capability

baseline;

Identify where errors in measurements can occur;

Start measuring the inputs, processes and outputs and collecting the data;

Validate that the problem exists based on the measurements;

Refine the problem or objective (from the Analysis phase)


What is the Process? How does it function?

Which Outputs affect CTQs most?

Which Inputs affect Outputs (CTQs) most?

Is our ability to measure/detect sufficient?

How is our current process performing?

What is the best that the process was designed to do?

The most applicable tools at this phase include the following:


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Fishbone Diagram to demonstrate the relationships between inputs and

outputs

Process Mapping - to understand the current processes and enables the team

to define the hidden causes of waste.

Preliminary Failure Mode & Effect Analysis (FMEA) - using this in the

Measure phase helps to identify and implement obvious fixes in order to

reduce defects and save costs as soon as possible.

Gauge Repeatability & Reproducibility (GR&R) - used to analyze the

variation of components of measurement systems so minimize any

unreliability in the measurement systems.

2.5.1.3 Analyze (A)

In the Analyze phase, the measurements collected in the Measure phase are analyzed

so that hypotheses about the root causes of variations in the measurements can be

generated and the hypothesis subsequently validated. It is at this stage that practical

business problems are turned into statistical problems and analyzed as statistical

problems. This includes:

generate hypotheses about possible root causes of variation and potential

critical

Inputs (Xs);

identify the vital few root causes and critical inputs that have the most

significant impact; and

Validate these hypotheses by performing Multivariate analysis.


Which Inputs actually affect our Critical to qualitys most (based on actual

data)?

By how much?

Do combinations of variables affect outputs?


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If input is changed, does the output really change in the desired way?

How many observations are required to draw conclusions?

What is the level of confidence?

The Analyze phase offers specific statistical methods and tools to isolate the key

factors that are critical for a comprehensive understanding of the causes of

defects:

Tests for normality (Descriptive Statistics, Histograms) this is used to

determine if the collected data is normal or abnormal so as to be properly

analyzed by other tools.

Correlation/Regression Analysis - to identify the relationship between

process inputs and outputs or the correlation between two different sets ofvariables.

Analysis of Variances (ANOVA) - this is an inferential statistical

technique designed to test for significance of the differences among two

or more sample means.

FMEA (Failure Mode and Effect Analysis) - applying this tool on current

processes enables identification of sufficient improvement actions to

prevent defects from occurring.

Hypothesis testing methods - these are series of tests in order to identify

sources of variability using historical or current data and to provide

objective solutions to questions, which are traditionally answered

subjectively.

Cause & Effect Matrix - to quantify how significant each input is for

causing variation of outputs.

2.5.1.4 Improve (I)

The Improve phase focuses on developing ideas to remove root causes of variation,

testing and standardizing those solutions. This involves:

identify ways to remove causes of variation;


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verify critical Inputs;

discover relationships between variables;

establish operating tolerances which are the upper and lower specification

limits (the engineering or customer requirement) of a process for judgingacceptability of a particular characteristic, and if strictly followed will

result in defect-free products or services;

Optimize critical Inputs or reconfigure the relevant process.


Once we know for sure which inputs most affect our outputs, how do we

control them?

How many trials do we need to run to find and confirm the optimal

setting/procedure of these key inputs?

Who should the old process be improved and what is the new process?

How much have Defects per Millions Opportunities (DPMO) decreased?

The most applicable tools at this phase are:

Process Mapping - this tool helps to represent the new process subsequent

to the improvements.

Process Capability Analysis (Cpk) - in order to test the capability of

process after improvement actions have been implemented to ensure we

have obtained a real improvement in preventing defects.

DOE (Design of Experiment) - This is a planned set of tests to define the

optimum settings to obtain the desired output and validate improvements.

2.5.1.5 Control (C)

The Control phase aims to establish standard measures to maintain performance and

to correct problems as needed, including problems with the measurement system.

This includes:

validate measurement systems;


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verify process long-term capability;

Implement process control with control plan to ensure that the same

problems dont reoccur by continually monitoring the processes that

create the products or services.


Once defects have been reduced, how do we ensure that the improvement

is sustained?

What systems need to be in place to check that the improved procedures

stay implemented?

What do we set up to keep it going even when things change?

How can improvements be shared with other relevant people in thecompany?

Most applicable tools at the Control phase include:

Control Plans this is a single document or set of documents that outlines

the actions, including schedules and responsibilities, which are needed to

control the key process inputs variables at the optimal settings.

Operating Flow Chart(s) with Control Points - this is a single chart or

series of charts that visually display the new operating processes.

Statistical Process Control (SPC) charts - these are charts that help to

track processes by plotting data over time between lower and upper

specification limits with a center line.

Check Sheets - this tool enables systematic recording and compilation of

data from historical sources, or observations as they happen, so that

patterns and trends can be clearly detected and shown (Hagemeyer and

Gershenson, 2005).


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2.6 Analytical tools for Six-Sigma and continuous improvement

The analytical tools of Six-Sigma have been used for many years in traditional

quality improvement programs. What makes their application to Six-Sigma unique is

the integration of these tools in a corporate wide management system. The tools

common to all quality efforts, including Six-Sigma, are flowcharts, run charts, Pareto

charts, histograms, check sheets, cause-and-effect diagrams, and control charts.

Examples of these, along with an opportunity flow diagram, are shown in Figure 2.1

to Figure 2.5 arranged according to DMAIC categories where they commonly

appear.

1. Flow charts. There are many types of flow charts. The one shown infigure 2.1 depicts the process steps as part of a SIPOC (supplier, input,

process, output and customer) analysis. SIPOC in essence is a formalized

input-output model, used in the define stage of a project.

Figure 2.1: An example of SIPOC analysis diagram for Define stage

(Hagemeyer,C. and Gershenson, J.K. (2005))


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2. Run charts shown in the Figure 2.2A. They depict trends in data over

time, and thereby help to understand the magnitude of a problem at the

define stage. Typically, they plot the median of a process.

3. Pareto charts shown in the Figure 2.2C. These charts help to break down a

problem into the relative contributions of its components. They are based

on the common empirical finding that a large percentage of problems are

due to a small percentage of causes. In the example, 80 percent of

customer complaints are due to late deliveries, which are 20 percent of the

causes listed.

4. Check sheets shown in Figure 2.2B. These are basic forms that help

standardize data collection. They are used to create histograms such as

shown on the Pareto chart.

5. Cause-and-effect diagrams. Also called fishbone diagrams, they show

hypothesized relationships between potential causes and the problem

under study. Once the C&E diagram is constructed, the analysis would

proceed to find out which of the potential causes were in fact contributing

to the problem. Example of cause and effect diagram shown in the Figure

2.3.

6. Opportunity Flow Diagram. This is used to separate value-added from

non-value added steps in a process. Example of opportunity flow diagram

shown in Figure 2.4.

7. Control charts shown in Figure 2.5. These are time-sequenced charts

showing plotted values of a statistic including a centerline average and

one or more control limits. It is used here to assure that changes

introduced are in statistical control.


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Figure 2.2: Example of charts for Measurement stage (Hagemeyer,C. and

Gershenson, J.K. (2005))


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Figure 2.3: An example of Cause and Effect diagram for analyze stage


Figure 2.4: An example of Opportunity flow diagram for Improve stage



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Figure 2.5: An example of Control chart for Control stage (Hagemeyer,C. and

Gershenson, J.K. (2005))

2.7 Six-Sigma versus Total Quality Management (TQM)

In some aspects of quality improvement, TQM and Six-Sigma share the same

philosophy of how to assist organizations to accomplish Total Quality. They both

emphasize the importance of top-management support and leadership. Both

approaches make it clear that continuous quality improvement is critical to long-term

business success. However, why has the popularity of TQM waned while Six

Sigma's popularity continues to grow in the past decade?

Pyzdek (2001) stated that the primary difference is management. Unlike TQM, Six-

Sigma was not developed by technicians who only dabbled in management and

therefore produced only broad guidelines for management to follow. The Six-Sigma

way of implementation was created by some of America's most gifted CEOs people

like Motorola's Bob Galvin, Allied Signal's Larry Bossidy, and GE's Jack Welch.

These people had a single goal in mind: making their businesses as successful as


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possible. Once they were convinced that tools and techniques of Six-Sigma could

help them do this; they developed a framework to make it happen. The differences

between TQM and Six-Sigma are summarized in Table 2.1

2.8 Six-Sigma versus Other Quality system or tools

2.8.1 ISO 9001 objectives

ISO 9001 is a Quality Management System, which includes specialized quality

management standards. A Quality Management System is a system of clearly defined

organizational structures, processes, responsibilities and resources used to assure

minimum standards of quality and can be used to evaluate an organizations overall

quality management efforts. An ISO 9001 certification assures a companys

customers that minimum acceptable system and procedures are in place in the

company to guarantee that minimum quality standards can be met.

2.8.1.1 Comparison of ISO 9001 with Six Sigma

ISO 9001 and Six-Sigma serve two different purposes. ISO 9001 is a quality

management system while Six-Sigma is a strategy and methodology for businessperformance improvement. ISO 9001, with guidelines for problem solving and

decision making, requires a continuous improvement process in place but does not

indicate what the process should look like while Six Sigma can provide the needed

improvement process. Meanwhile, Six-Sigma does not provide a template for

evaluating an organizations overall quality management efforts whereas ISO 9001

does.

2.8.1.2 Combining Six Sigma with ISO

Six-Sigma provides a methodology for delivering certain objectives set by ISO such

as:

prevention of defects at all stages from design through servicing


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statistical techniques required for establishing, controlling and verifying

process capability and product characterization

investigation of the cause of defects relating to product, process and quality

system

Continuous improvement of the quality of products and services.

Six-Sigma supports ISO and helps an organization satisfying the ISO requirements.

Further, ISO is an excellent vehicle for documenting and maintaining the process

management system involving Six Sigma. Besides, extensive training is required by

both systems for successful deployment.

2.8.2 Lean Manufacturing Objectives

Lean manufacturing, also called Lean Production, is a set of tools and methodologies

that aims for the continuous elimination of all waste in the production process. The

main benefits of this are lower production costs; increased output and shorter

production lead times. More specifically, some of the goals include:

1. Defects and wastage - Reduce defects and unnecessary physical wastage,

including excess use of raw material inputs, preventable defects, costs

associated with reprocessing defective items and unnecessary product

characteristics, which are not required by customers.

2. Cycle Times - Reduce manufacturing lead times and production cycle times

by reducing waiting times between processing stages, as well as process

preparation times and product/model conversion times.

3. Inventory levels - Minimize inventory levels at all stages of production,

particularly works-in-progress between production stages. Lower inventories

also mean lower working capital requirements.

4. Labor productivity - Improve labor productivity, both by reducing the idle

time of workers and ensuring that when workers are working, they are using

their effort as productively as possible (including not doing unnecessary tasks

or unnecessary motions).


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5. Utilization of equipment and space - Use equipment and manufacturing space

more efficiently by eliminating bottlenecks and maximizing the rate of

production though existing equipment, while minimizing machine downtime.

6. Flexibility - Have the ability to produce a more flexible range of products

with minimum changeover costs and changeover time.

7. Output Insofar as reduced cycle times, increased labor productivity and

elimination of bottlenecks and machine downtime can be achieved,

companies can generally significantly increased output from their existing

facilities. Most of these benefits lead to lower unit production costs for

example, more effective use of equipment and space leads to lower

depreciation costs per unit produced, more effective use of labor results in

lower labor costs per unit produced and lower defects lead to lower cost ofgoods sold.

2.8.2.1 Comparison with Six Sigma

Both Six Sigma and Lean Manufacturing have unique strengths and they integrate

well. Lean is broader in nature since it sets the broad objective of eliminating all

waste, and recommends certain processes for achieving that. When the objective is

process design, factory layout, waste reduction and the way to accomplish theobjectives is known, Lean tools and approaches are recommended. Six-Sigma is

more focused in nature since it a set of tools for achieving clearly defined

improvements, which are likely to help make the company leaner. Six-Sigma

provides a richer infrastructure and tool set for problem solving especially with

unknown causes and solutions.

2.8.2.2 Combining Lean Manufacturing with Six Sigma

It is quite common for companies to combine Lean Manufacturing with Six Sigma in

what is sometimes called Lean Six Sigma. The two are quite complementary since

Six Sigma is a useful tool for helping to make the company more lean. Likewise,

some of the processes often used in lean manufacturing may be the solutions to

problems addressed in a Six-Sigma project (Bendell, 2006)


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Table 2.1: TQM VS Six-Sigma

2.8.4 Comparison between six sigma DMAIC and PDCA


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Table 2.2:- Comparison between DMAIC and PDCA (Summers, D.C.S. (2003))

DMAIC PDCA

Steps SIX SIGMA:-

1. Select appropriate metrics:- Key Process Output

Variables (KPOVs)

2. Determine how these metrics will track over time

3. Determine current baseline performance of

project/process

4. determine the Key Process Input Variables

(KPIVs) that drives the Key Process Output

Variables (KPOVs)

5. Determine what changes used to be made to the

key process input variables in order to positively

affects the key process output variables

6. Makes changes

7. Determine if the changes have positively

affected the KVOPs

8. If the changes made result in performance

improvements establish control of the KVIPs and

the need new levels. If the changes have not

resulted in performance improvement return to

step 5 and make the appropriate changes.

Plan:-

1. Recognize a problemexist

2. Foam quality

improvement team

3. Clearly define the

problems

4. Develop performance

measures

5. Analyze

problem/process

6. Determine possible

causes

Do:-1. Select and implement

solution

Study:-

1. Evaluate solution

Act:-

1. Ensure permanence

2. Continuous

improvement

2.9 Case study: An example of DMAIC at American Express

In this case the customer is using Six-Sigma to reduce defects in a service.


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2.9.1 The general situation

A number of merchants that accept American Express cards fail to place point of

purchase materials (e.g., decals) that notify customers that they can use these cards at

these establishments while displaying competing (e.g., Visa, MasterCard, etc.) point

of purchase materials. American Express defines these merchants as passive

suppressors.

In an effort to increase visibility, an external vendor that placed point-of-purchase

material in the marketplace identified passive suppressors, and measured placement

and passive suppression rates was hired by American Express. However, the vendor

had a significant rate of failure to contact or meet with the merchants. The leadingreason for not meeting with the merchant was that the store was closed when the

vendor stopped by.

2.9.3 Define and Measure

The objective was to reduce closed store uncallables (failures to contact), which

represented 27.4 percent of total uncallables and 8.0 percent of the annualized

attempted visits. The process represented a 2.9-sigma level and 80,000 defects per

million opportunities.

2.9.3 Analyze

A Pareto chart pointed to the closed store category as the number one reason for

uncallables. By shadowing the vendor on merchant visits, American Express learned

that the visits took place between 8:00 A.M. and 6:00 P.M. Of the closed stores, 45percent were retail establishments and 16 percent were restaurants. Typically, these

two types of establishments are not open before 10:00 A.M. therefore; American

Express hypothesized that the hours the vendor was calling on the merchant

contributed to the high uncallable rate. It also was determined that if an

establishment was closed, the inspection process was terminated with the merchant


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being reported as uncallable without first checking to see if any point-of-purchase

materials were visible from the outside. This resulted in merchants who displayed

point-of-purchase material being visited multiple times leading to rework.

2.9.4 Improve

American Express then tested and validated their hypotheses. The call hours for all

visits were changed to begin after 10:00 A.M. The vendor was required to continue

the inspection process with respect to external placement of point-of-purchase

material. The first change, revised calls hours, resulted in a decrease to 4.5 percent

from 8.0 percent in the defect rate. The second change, continued inspection,

indicated that 35.4 percent of the remaining 4.5 percent closed stores actually had

external point-of-purchase material displayed. Combined, these two changes had the

following effects: the defect rate decreased to 2.8 percent, the number of defects per

million decreased to 28,000, and the sigma level increased to 3.2.

2.9.6 Control

In order to achieve control, American Express uses a p control chart to track the

proportion of closed stores over time and the vendor call report was revised to reflect

the uncallable rate by reason (Sai Kim, 2000).

2.10 Summary

As a conclusion for this chapter, it gives a brief explanation regarding the quality

approaches. In order to achieve excellent quality, the challenge is to make certain

that a quality program really does have a customer focus and is sufficiently agile to

be able to make improvements quickly without losing sight of the real time needs of

the business. The quality system must be analyzed for its own quality. There is also a

need for sustaining a quality culture over the long haul.


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CHAPTER 3

RESEARCH METHODOLOGY

3.1 Introduction

This chapter will discuss briefly about the selected company and the area focused for

this thesis. Besides that, this chapter also discussed the research methodology which

were used in this research and also the Gantt chart which attached to indicate the

planning process for this research.

3.2 Company selection

This thesis, which is actually a case study, were conducted in XXX a Japanese

company. This case study was focused on 18 and 30 tone injection molding assembly

line of part production department of the company which is located at the Nilai,

Negeri Sembilan, Malaysia plant. The departments main production is remote

control and small plastic components which produced for internal and external

customers. Further information of the company will discuss in chapter 4, company

profile.

3.3 Methodology

The methodology adapted for this case study is by applying the six sigma project

methodology which are Define, Measure, Analyze, Improve and Control, (DMAIC)


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methodology. This methodology is done in two semesters, first semester starts with

selecting a company to do the case study until first stage of DMAIC methodology

(PSM 1) and second semester starts with the measure stage and culminates with final

stage of DMAIC methodology (PSM 2). The methodology of this research is shown

in Figure 3.1.


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3.3.1 Define stage

The purpose of the Define phase is to clearly identify the problem, the requirements

of the project and the objectives of the project. In this stage rejection data will be

collected and tabulated to foam a pareto diagram to identify the main rejection

problem. A team will be formed to brainstorm and produce a fish bone diagram to

identify the major contribution for the main rejection problem.

3.3.2 Measure stage

Depending on whether it is a new or old process investigated during the project, a

method and what kind of response (Y) to measure the performance of the process has

to be developed (new). If it is an existing process, evaluate the accuracy and

variation of the measurement system and also determine the current process

performance. Most importantly identify the input variables that cause variation in the

process performance. Benham (2003), Montgomery (2001b) and GE-DMAIC all

claims that to ensure that the measurement system is adequate to measure the Y, a

gauge R&R study must be done. The project team should then gain consensus on any

actions needed regarding the measurement system. It is important to build up an

understanding of the measurement system, which includes operators, gauges andenvironment.

Fishbone Diagram to demonstrate the relationships between inputs and

outputs

Process Mapping - to understand the current processes and enables the

team to define the hidden causes of waste.

3.3.3 Analyze stage

In all quality work it is not enough to define the problem collect and display the

suitable data. The data also needs to be analyzed so the sources of variation are

identified. Mostly there is more than one cause of variation, but there is usually a


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root cause more important than the other causes, this root cause has to be identified

and eliminated later on.

Cause & Effect Matrix - to quantify how significant each input is for

causing variation of outputs.

Why and why analysis to identify the problems

3.3.4 Improve stage

The root cause that was found during the measure phase must now be eliminated; the

process is also to be optimized. A number of solutions to solve the problem will be

suggested with the root cause are generated and the one that best addressees the root

cause is chosen. To optimize the process a designed experiment is usually conducted,

the input variables are set to achieve the optimum output.

3.3.5 Control stage

The final phase of the DMAIC roadmap is control. In this stage the control method

will be suggested but in actual after implementing the improvements, evidence is

needed to prove that the process is in control and is more capable than before the

improvements. If the process is more capable than before it is important to keep and

maintain this new higher quality level. Statistical process control and especiallycontrol charts mainly do this.

3.4 Techniques used in identifying the general and major problem

Apart from six sigma DMAIC methodology, other techniques needed during the

study are:-

3.4.1 Interview

In identifying the problems interviews are conducted with the Quality Assurance

engineer in the assembly operation department. The questions were focused mainly

in the category of man, machine, material, method and also company policy.


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3.4.3 Observation

Through observation, the specific problem of the department can be understood.

Normally the observation period is within one to two hours per day. The process

flow in the assembly line was also observed.

3.4.3 Data Collection

Data was collected from the assembly line to find out where the problem lies. Data

such as the actual time of each activity was carried out, number of rejected items,

targeted value of each day and actual quantity production was taken. Thus the

problem based on the data can be identified and then analyzed to determine where

the actual problem lies. Statistical Process Control (SPC) tools were used to analyze

the quality problem.


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3.5 Gantt chart Table 3.1: Gantt chart

2007 2008No Activity

Jul Aug Sept Oct Nov Dec Jan Feb Mac Apr

1Selecting company and Problemstatement identification

2 Research Scope and Objective

3 Findings Literature Review

4 Research methodology

5 Start doing the report writing

6Presentation Preparation for PSM1 (Proposal)

7 Report Review

8 PSM 1 report Submission

9 Presentation for PSM 1

10 Data collection Measure stage

11 Data Collection and analysis stage

12Prepare suggestion forimprovement and control

13 Result analysis and discussion

14Report writing for PSM 2 (Finalreport)

15 PSM 2 Presentation

16 Hard Cover Submission

Actual Planning


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44

3.6 Summary

The methodology of the thesis is identified. This methodology will be used as

guidance throughout this project. This is so that a more systematic methodology will

be done.


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4.4 Companys Product

Figure4.3: Remote controllers

AAuuddiioo VViiddeeoo ttyyppee ((TTVV,, DDVVDD ,,VVCCRR))

AAiirrCCoonnddiittiioonneerrttyyppee

CCaammeerraa ttyyppee

TTooiilleettrryy ttyyppee

AAuuttoommoottiivvee ttyyppee


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4.5 Introduction to Injection Moulding

Injection moulding is a manufacturing technique for making parts from thermoplastic

material in production. Molten plastic is injected at high pressure into a mould,

which is the inverse of the product's shape. After a product is designed by an

Industrial Designer or an Engineer, moulds are made by a mould maker (or

toolmaker) from metal, usually either steel or aluminum, and precision-machined to

form the features of the desired part. Injection moulding is widely used for

manufacturing a variety of parts, from the smallest component to entire body panels

of cars. Injection moulding is the most common method of production.

Injection moulding machines, also known as presses, hold the moulds in which the

components are shaped. Presses are rated by tonnage, which expresses the amount of

clamping force that the machine can generate. This pressure keeps the mould closed

during the injection process. Tonnage can vary from less than 5 tons to 6000 tons,

with the higher figures used in comparatively few manufacturing operations.

Injection moulding machines can fasten the moulds in either a horizontal or vertical

position. The majority is horizontally oriented but vertical machines are used in some

niche applications such as insert moulding, allowing the machine to take advantage

of gravity. There are many ways to fasten the tools to the platens, the most common

being manual clamps (both halves are bolted to the platens); however hydraulic

clamps (chocks are used to hold the hold the tool in place) and magnetic clamps are

also used. The magnetic and hydraulic clamps are used where fast tool changes are

required.

Machines are classified primarily by the type of driving systems they use: hydraulic,

electric, or hybrid. Hydraulic presses have historically been the only option available

to moulders until Nissei introduced the first all electric machine in 1983. The electric

press, also known as Electric Machine Technology (EMT), reduces operation costs

by cutting energy consumption and also addresses some of the environmental

concerns surrounding the hydraulic press. Electric presses have been shown to be

quieter, faster, and have a higher accuracy; however the machines are more


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expensive. Hybrid injection moulding machines take advantage of the best features

of both hydraulic and electric systems. Hydraulic machines are the predominant type

in most of the world, with the exception of Japan.

Robotic arms are often used to remove the moulded components; either by side or

top entry, but it is more common for parts to drop out of the mould, through a chute

and into a container.

Figure 4.4: Sumitomo Injection Moulding Machine

4.5.1 Injection Molding Cycle & Process

The basic injection cycle is as follows: Mould closes - injection carriage forward -

inject plastic - metering - carriage retract - mould open - eject part(s). The moulds are

closed shut by hydraulics or electric, and the heated plastic is forced by the pressure

of the injection screw to take the shape of the mould. Some machines are run by

electric motors instead of hydraulics or a combination of both. The water-cooling


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channels then assist in cooling the mould and the heated plastic solidifies into the

part. Improper cooling can result in distorted moulding or one that is burnt. The cycle

is completed when the mould opens and the part is ejected with the assistance of

ejector pins within the mould.

The resin, or raw material for injection moulding, is usually in pellet or granule form,

and is melted by heat and shearing forces shortly before being injected into the

mould. Resin pellets are poured into the feed hopper, a large open bottomed

container, which feeds the granules down to the screw. The screw is rotated by a

motor, feeding pellets up the screw's grooves. The depth of the screw flights

decreases towards the end of the screw nearest the mould, compressing the heated

plastic. As the screw rotates, the pellets are moved forward in the screw and theyundergo extreme pressure and friction which generates most of the heat needed to

melt the pellets. Heaters on either side of the screw assist in the heating and

temperature control during the melting process.

The channels through which the plastic flows toward the chamber will also solidify,

forming an attached frame. This frame is composed of the sprue, which is the main

channel from the reservoir of molten resin, parallel with the direction of draw, and

runners, which are perpendicular to the direction of draw, and are used to convey

molten resin to the gate(s), or point(s) of injection. The sprue and runner system can

be cut or twisted off and recycled, sometimes being granulated next to the mould

machine. Some moulds are designed so that the part is automatically stripped through

action of the mould.


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Table 4.1: Injection moulding cycle

Step #1 - The uncured rubber is fed into the

machine in the form of a continuous strip.

Step #2 - The uncured rubber is worked and warmed

by an auger screw in a temperature controlled barrel.

Step #3 - As the rubber stock accumulates in the

front of the screw, the screw is forced backwards.

When the screw has moved back a specified

amount, the machine is ready to make a shot.

Step #5 - While the rubber cures in the heated mold,

the screw turns again to refill.

Step #4 - With the mold held closed under hydraulic

pressure, the screw is pushed forward. This forces the

rubber into the mold, similar to the action of a

hypodermic syringe.

Step #6 - The mold opens and the part can be

removed. The machine is ready to make the next shot,

as soon as the mold closes.


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4.5.2 Moulding Defects

Table 4.2: Common moulding defects

Moulding Defects Alternative name Descriptions Causes

Blister Blistering /Peeling

Raised or layered zoneon surface of the part

Tool or material is too hot, often caused by a lack ofcooling around the tool or a faulty heater

Burn Marks Air Burn Localised burnt zone

(often in theyellow/brown tones)

Tool lacks venting, injection speed is too high

Black dot Dirt like spots on

material

Material over heat, dust, mix up of material and etc

Crack Part broken External forces and etc

Color Streaks Localised change of

color

Masterbatch isn't mixing properly, or the material has

run out and it's starting to come through as natural only

Delamination Thin mica like layers

formed in part wall

Contamination of the material e.g. PP mixed with ABS,

very dangerous if the part is being used for a safety

critical application as the material has very littlestrength when delaminated as the materials cannot bond

Flash Excess material in thin

layer exceeding normal

part geometry

Tool damage, too much injection speed/material

injected

Embedded

contaminates

Embedded

Particulates

Foreign particle (burnt

material or other)embedded in the part

Particles on the tool surface, contaminated material or

foreign debris in the barrel, or too much shear heatburning the material prior to injection

Flow marks Directionally "off tone" Injection speeds too slow (the plastic has cooled down


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wavy lines or patterns too much during injection, injection speeds must be set

as fast as you can get away with at all times)

Jetting Deformed part byturbulent flow of

material

Poor tool design

Silver streaks Circular pattern aroundgate caused by hot gas

Sink Marks Localised depression (In

thicker zones)

Holding time/pressure too low, cooling time too low,

with sprueless hot runners this can also be caused by

the gate temperature being set too high

(Source: XXX Part Production, Injection Moulding Manual)

Splay Marks Splash mark /

Silver Streaks

Circular pattern around

gate caused by hot gas

Splay Marks

Short shot Fill / Short

mould

Partial part Lack of material, injection speeds too slow

Stringiness String like remain from

previous shot transfer in

new shot

Gate hasn't frozen off

Weld line Knit Line Discolored line where

two

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