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MASTER’S THESIS
2004:070 CIV
Evaluation of possible
SIX SIGMA implementation
including aDMAIC project
A case study at the Cage Factory, SKF Sverige AB
MASTER OF SCIENCE PROGRAMME
Department of Business Administration and Social Science
Division of Quality & Environmental Management
2004:070 CIV • ISSN: 1402 - 1617 • ISRN: LTU - EX - - 04/70 - - SE
MARTIN LENNARTSSON
ERIK VANHATALO
-TITLES-
Evaluation ofpossibleSIXSIGMAimplementation
including aDMAICproject
- A CASE STUDY AT THE CAGE FACTORY, SKF SVERIGE AB
Utvärdering av möjlig SEX SIGMA implementering
samt ett DMAIC-projekt
- EN FALLSTUDIE PÅ HÅLLAREFABRIKEN, SKF SVERIGE AB
This Master Thesis was carried out within the area of Quality Management
at Luleå University of Technology and SKF Sverige AB.
By:
Martin Lennartsson
Erik Vanhatalo
Luleå 2004-02-29
Supervisors:
Lars Palmqvist, SKF Sverige AB in Gothenburg
Karin Schön, Luleå University of Technology
-ABSTRACT-
ABSTRACT
Six Sigma is an initiative launched by Motorola in 1987, focusing on
reducing variation and continuously improving processes (Barney, 2002).
This thesis was carried out at the Cage Factory in Gothenburg, a smaller unit
within SKF Sverige AB with 124 employees. The factory manufactures the
cage component in the bearing, which will keep the rollers in place in the
complete bearing.
The purpose of this thesis is to investigate and make comparisons between
Six Sigma and the existing way of working with improvements and the
organization in the Cage Factory and to give recommendations on what
actions are needed to efficiently implement Six Sigma.
To aid in the fulfillment of the purpose a practical DMAIC (Define-
Measure-Analyze-Improve-Control) project was conducted. The project
aims to reduce customer complaints and downtime caused by the turning
activity in one of the production channels at the Cage Factory. Furthermore,
several interviews with strategically selected individuals were conducted.
The authors argue that SixSigma could be implemented and integrated with
the existing improvement approach, Total Process Management, TPMG. Six
Sigma can be used to attack the most complex problems, while TPMG
handles the many day-to-day issues.
At the moment the implementation strategy "Strategically selected
individuals and projects" is the most applicable at the Cage Factory. The
authors argue that SixSigma will provide a structure (DMAIC) and training
in tools, thereby ensuring that the tools are used at the right time and in the
right way at the Cage Factory.
In the future, there has to be a strategy for generating possibleSixSigma
projects at the Cage Factory. Also, it is important that a way for steering
different problems to different problem solving activities is developed.
However, some issues need to be considered if SixSigma should work
efficiently at the Cage Factory. A training venture is needed to enable the
introduction of different roles in the organization. Also, all training should
be connected to practical experience. It is important that the Cage Factory
receives resource support from SKF Sverige and/or the SKF Group. Further,
a reliable measurement system must be implemented. The authors believe
that improved scrap reporting and improved use of SPC are important
actions that need to be taken.
-SAMMANFATTNING-
SAMMANFATTNING
Sex Sigma fokuserar på att reducera variation samt att kontinuerligt förbättra
företagets processer och introducerades av Motorola 1987 (Barney, 2002).
Detta examensarbete har utförts på Hållarefabriken i Göteborg som är en
mindre enhet inom SKF Sverige AB med 124 anställda. Fabriken producerar
hållarkomponenten i lagret som har till uppgift att hålla rullar på plats i det
färdiga lagret.
Syftet med examensarbetet är att utvärdera och jämföra Sex Sigma med det
rådande förbättringsarbetet och organisationen på Hållarefabriken samt att
ge rekommendationer på vad som bör åtgärdas för att effektivt kunna införa
Sex Sigma.
För att uppfylla syftet har bland annat ett DMAIC-projekt utförts. Projektets
syfte är att reducera antalet kundreklamationer och minska stopptid orsakade
av svarvning i en av produktionskanalerna på Hållarefabriken. Vidare har ett
antal intervjuer genomförts med strategiskt utvalda individer.
Författarna menar att Sex Sigma kan implementeras och integreras i det
nuvarande förbättringsarbetet, Total Process Management (TPMG). Sex
Sigma kan användas för att attackera de mest komplexa problemen inom
verksamheten, medan TPMG hanterar de vardagliga åtgärderna som krävs
för att utveckla verksamheten på lång sikt.
För tillfället är implementeringsstrategin "strategiskt utvalda individer och
projekt" den mest lämpliga för Hållarefabriken. Författarna anser att Sex
Sigma kommer att ge en struktur (DMAIC) och träning i verktyg, vilket i sin
tur innebär att verktygen används vid rätt tillfälle och på rätt sätt på
Hållarefabriken.
I framtiden måste det finnas en strategi för att generera möjliga Sex Sigma-
projekt på Hållarefabriken. Dessutom är det viktigt att det utvecklas ett sätt
att styra olika problem till olika problemlösningsalternativ.
Det finns dock en del åtgärder som måste vidtas för att Sex Sigma ska kunna
fungera effektivt på Hållarefabriken. En utbildningssatsning krävs för att
möjliggöra en introduktion av roller i organisationen. All utbildning bör
dessutom ske i samband med deltagandet i ett praktiskt projekt. Det är
viktigt att Hållarefabriken får stöd, i form av resurser, från SKF Sverige och
SKF-koncernen. Författarna anser att en förbättrad kassationsrapportering
och förbättrad användning av programvaran för SPS är viktiga åtgärder för
att skapa ett väl fungerande mätsystem.
-ACKNOWLEDGEMENTS-
ACKNOWLEDGEMENTS
This Master Thesis was carried out during the period from late September
2003 to early February 2004 at the Cage Factory, SKF Sverige AB in
Gothenburg, Sweden.
We would like to take the opportunity to thank SKF Sverige AB and
especially the Cage Factory's entire staff for giving us the opportunity to
write our Master Thesis by studying their organization.
Furthermore, we also wish to thank our supervisor at Luleå University of
Technology, Luleå, LTU, Karin Schön as well as our supervisor at the Cage
Factory Lars Palmqvist for their valuable support during the completion of
this Thesis.
Moreover, the authors would like to express a special thanks to the members
of the improvement group taking part in the DMAICproject presented in
this Thesis. Without their committed participation this Thesis' completion
wouldn't have been possible. Also, we thank all the different individuals that
gave us some of their valuable time taking part in the interviews made in this
Thesis.
Last but not least, we would like to thank the Division of Quality and
Environmental Management at LTU for the opportunity to complete our
Master's study at their Division and for support during this and earlier
courses. Especially we would like to thank Görgen Edenhagen, Master
Thesis Coordinator and fellow course mates giving us feedback at Master
Student's seminars.
Gothenburg, February 2004
Martin Lennartsson Erik Vanhatalo
-CONTENTS-
CONTENTS
LIST OF FIGURES, PICTURES AND TABLES 1
FIGURES 1
PICTURES 2
TABLES 2
LIST OF ABBREVIATIONS 3
1. INTRODUCTION 4
1.1. BACKGROUND 4
1.1.1. The development of quality engineering 4
1.1.2. Company presentation 6
1.2. PROBLEM DISCUSSION 8
1.3. PURPOSE AND DELIMITATIONS 10
1.3.1. Purpose of the thesis 10
1.3.2. Delimitations 10
1.4. THE OUTLINE OF THE THESIS 11
2. METHODOLOGY 12
2.1. RESEARCH APPROACH 12
2.1.1. Positivism or Hermeneutics 12
2.1.2. Induction or Deduction 13
2.1.3. Quantitative or Qualitative method 14
2.2. RESEARCH STRATEGY 14
2.3. LITERATURE STUDY 15
2.4. CHOICE OF DATA COLLECTION METHOD 16
2.4.1. Primary data 16
2.4.2. Secondary data 18
2.5. METHODOLOGY AND CHOSEN TOOLS IN THE DMAICPROJECT 18
2.6. RELIABILITY AND VALIDITY 19
2.6.1. Validity 19
2.6.2. Reliability 20
3. THEORETICAL FRAME OF REFERENCE 21
3.1. SIXSIGMA 21
3.1.1. The SixSigma Framework 23
3.1.2. The SixSigma Infrastructure 24
3.1.3. Strategies for SixSigmaImplementation 25
3.1.4. Critique to SixSigma 27
3.2. THE DMAIC IMPROVEMENT CYCLE 28
-CONTENTS-
3.2.1. How to choose aSixSigmaproject 29
3.2.2. The Define Phase 29
3.2.3. The Measure Phase 30
3.2.4. The Analyze Phase 31
3.2.5. The Improve Phase 31
3.2.6. The Control Phase 31
3.2.7. Examples of tools in the different phases 32
3.2.8. Tools Chosen in the DMAICproject 33
3.3. OTHER QUALITY INITIATIVES 34
3.3.1. Total Quality Management, TQM 34
3.3.2. Total Process Management and TPM, the SKF way 35
3.4. TURNING 37
4. THE EMPIRICAL STUDY 38
4.1. THE DMAICPROJECT 38
4.1.1. The Define Phase 38
4.1.2. The Measure Phase 41
4.1.3. The Analyze Phase 47
4.1.4. The Improve Phase 49
4.1.5. The Control Phase 52
4.1.6. Evaluationof the DMAICproject 53
4.2. INTERVIEWS 54
4.2.1. Lars Arrenäs, TPMG Manager, SKF 55
4.2.2. Cecilia Lack, TPMG Coordinator at the Cage Factory 56
4.2.3. Folke Höglund, Quality Assurance Manager, SKF Group 57
4.2.4. Bo Bergman, Professor, Chalmers University of Technology, CTH 59
4.2.5. Laszlo Persson, Master Black Belt at Volvo Cars Engine in Skövde 61
4.3. FOCUS GROUP AT THE CAGE FACTORY 68
5. ANALYSIS AND RESULTS 72
5.1. EXPERIENCE FROM THE DMAICPROJECT 72
5.1.1. The scope of the project 72
5.1.2. The cost issue 73
5.1.3. Collection and evaluationof data 73
5.1.4. DMAIC methodology, tools and results 74
5.2. ANALYSIS OFSIXSIGMAIMPLEMENTATION AT THE CAGE FACTORY 76
5.2.1. Why adopt Six Sigma? 76
5.2.2. The SixSigma Framework at the Cage Factory 77
5.2.3. Organization and SixSigma Roles 80
5.2.4. Methodology and Tools 81
-CONTENTS-
6. CONCLUSIONS AND DISCUSSION 82
6.1. CONCLUSIONS 82
6.2. DISCUSSION 83
6.2.1. Thesis generalization 83
6.2.2. Criticism to sources and methodology 83
6.2.3. Problems with the purpose of the thesis 85
6.2.4. Future work 85
REFERENCES 86
BIBLIOGRAPHIC REFERENCES 86
ELECTRONIC REFERENCES 87
PAPER REFERENCES 88
ORAL REFERENCES 88
OTHER REFERENCES 89
SUPPLEMENTS 90
APPENDICES 102
GLOSSARY 110
INDEX 111
-CONTENTS-
LIST OF FIGURES, PICTURES AND TABLES
Figures
Page
FIGURE 1.1 DEVELOPMENT OF THE QUALITY CONCEPT 5
FIGURE 1.2 THE SKF BUSINESS CONCEPT 6
FIGURE 1.3 THE SKF QUALITY POLICY 7
FIGURE 1.4 SKETCH OF THE WORKFLOW IN CHANNEL 13 AT THE CAGE FACTORY 9
FIGURE 2.1 INDUCTIVE AND DEDUCTIVE APPROACH IN RESEARCH 13
FIGURE 3.1 NORMALLY DISTRIBUTED PROCESS PERFORMING AT SIXSIGMA LEVEL 22
FIGURE 3.2 COSTS, IN PER CENT OF TURNOVER, DEPENDING ON SIGMA LEVEL 22
FIGURE 3.3 THE CORPORATE FRAMEWORK OFSIXSIGMA 23
FIGURE 3.4 STRUCTURE OFA GENERAL SIXSIGMAPROJECT 25
FIGURE 3.5 STRATEGIES FOR SIXSIGMAIMPLEMENTATION 26
FIGURE 3.6 THE DMAIC METHODOLOGY 28
FIGURE 3.7 COMMONLY USED SOURCES FOR PROJECT GENERATION 29
FIGURE 3.8 VARIATION IN INPUT VARIABLES ARE TRANSFERRED TO THE OUTPUT 30
FIGURE 3.9 COMMONLY USED TOOLS IN ADMAICPROJECT 33
FIGURE 3.10 QUALITY TOOLS IN THE DMAICPROJECT 33
FIGURE 3.11 LINK BETWEEN VALUES, METHODOLOGIES AND TOOLS 35
FIGURE 3.12 THE OPERATOR MAINTENANCE STAIRCASE 36
FIGURE 3.13 THE CONCEPT OF LONGITUDINAL AND FACE TURNING 37
FIGURE 4.1 PARETO CHART OVER CUSTOMER COMPLAINTS 39
FIGURE 4.2 HISTORICAL DEVELOPMENT OF COMPLAINTS IN CHANNEL 13 39
FIGURE 4.3 PARETO CHART FOR IDENTIFIED COMPLAINT CAUSES IN CHANNEL 13 39
FIGURE 4.4 PROCESS MAP OF THE TURNING ACTIVITY 41
FIGURE 4.5 PIE CHART OF DOWNTIME IN DIFFERENT MACHINES IN CHANNEL 13 42
FIGURE 4.6 PARETO CHART OF DURATIONS FOR DIFFERENT CAUSES 43
FIGURE 4.7 RESULT OF THE FREQUENCY STUDY IN THE TURNING PROCESS 44
FIGURE 4.8 THE OUT OF CONTROL SITUATION FOR ONE OF THE STUDIED CAGES 49
FIGURE 4.9 THE KANO MODEL 60
FIGURE 4.10 SKETCH OF THE SIXSIGMA ORGANIZATIONAL STRUCTURE AT VCES 64
FIGURE 4.11 PROJECT LIFE AND RESPONSIBILITIES AT VCES 65
FIGURE 4.12 PROBLEM SOLVING ACTIVITIES AT VCES 65
FIGURE 5.1 HOW SIXSIGMA AND TPMG DEALS WITH PROBLEMS 77
FIGURE 5.2 TPMG AND SIXSIGMA AT THE CAGE FACTORY 79
FIGURE S.1 PROJECT CHARTER USED IN THE DMAICPROJECT 92
FIGURE S.2 FREQUENCY STUDY FORM USED IN THE DMAICPROJECT 93
FIGURE S.3 CAUSE-AND-EFFECT DIAGRAM FROM THE DMAICPROJECT 95
-1-
-CONTENTS-
FIGURE S.4 PROCESS-FMEA DEVELOPED IN THE DMAICPROJECT 98
FIGURE S.5 TREE DIAGRAM DEVELOPED IN THE DMAICPROJECT 100
FIGURE S.6 MATRIX DIAGRAM DEVELOPED IN THE DMAICPROJECT 101
FIGURE A.1 CONVERTING DPMO TO SIGMA VALUES 103
FIGURE A.2 THE SEVEN-TIMES-SEVEN TOOLBOX 104
Pictures
PICTURE 1.1 CAGE AND RADIAL BEARING 7
PICTURE 4.1 THE IMPROVEMENT GROUP 42
PICTURE 4.2 DEFECTS IN THE TURNING ACTIVITY 44
Tables
TABLE 4.1 CUSTOMER COMPLAINTS PER PRODUCTION CHANNEL 38
TABLE 4.2 POTENTIAL FAILURE CAUSES WITH THE HIGHEST RPN 48
TABLE 4.3 MEASURES FROM THE TREE DIAGRAM WITH 18 POINTS 50
TABLE 4.4 MEASURES CORRELATED TO PROBLEMS DETECTED IN THE FMEA 51
TABLE S.1 THE CUSTOMER COMPLAINT PROCESS 96
TABLE A.1 TRAINING CONTENT FOR DIFFERENT ROLES 103
-2-
[...]... Therefore an evaluationofSixSigmaimplementation in the Cage Factory is valuable In a traditional organization the structure is designed to carry out routine tasks In SixSigma most activities and problems are unique (Pyzdek, 2003) What is this demanding of the SixSigma Company? A company that aims for an implementationofSixSigma also has to consider ongoing improvement activities and systems Management... interpretations and analysis of these sources of data, founded upon interpretations of existing theories, are examples ofa hermeneutic approach -12- -METHODOLOGYHowever, there are also elements of Positivism The DMAICproject concerning the turning related problems also includes quantitative data and logical and factbased decisions, a positivistic approach In fact, the evaluationofapossibleSixSigma implementation. .. deal with quality problems in a manufacturing company The past 15-20 years many new methods, strategies and tools have emerged in the quality area, for example Total Quality Management, TQM, has been a popular approach that many companies have adopted (Pande et al., 2000) In recent years SixSigma has grown in popularity especially in the US and companies like General Electric and Motorola have obtained... qualitative and quantitative methods because advantages and drawbacks with each method complement each other In this thesis there are elements of both qualitative and quantitative data or information The majority of the data or information gathered is ofa qualitative nature, in the form of interviews, focus groups and the use of qualitative tools in the improvement project However, quantitative data... implementationofSixSigma and the use ofSixSigma methodology it is necessary to present relevant theory about SixSigma This section treats theory about the Framework, infrastructure, and implementation strategies in SixSigma Also, critique to SixSigma is presented Pande et al (2000) give a definition ofSixSigma as follows: "A comprehensive and flexible system for achieving, sustaining and maximizing... companies traditionally have accepted that their processes perform at a level of three to four sigma, which translates to 6,200 to 67,000 dpmo According to SixSigmaa manufacturing process with a normally distributed output and a standard deviation6, , has to display a distance ofsix standard deviations between process target and the closest tolerance limit and corresponds to a Process Capability Ratio... variation (Barney, 2002) In 1988 Motorola won the Malcolm Baldridge National Quality Award, MBNQA1 and the interest for SixSigma increased (Pyzdek, 2001) Since Motorola launched SixSigma in 1987 and particularly from 1995, a growing number of global companies have followed, developing SixSigma programs of their own (Magnusson, Kroslid & Bergman, 2003) Today, SixSigma is well established in the automotive,... strategies for Six Sigma: "The SixSigma Organization", "The SixSigma Engineering Organization" and "Strategic selection of individuals and projects" The differences between these three strategies and their strengths and weaknesses are illustrated in Figure 3.5 -25- -THEORETICAL FRAME OF REFERENCESix Sigma Organization SixSigma Engineering Organization Strategically selected projects and individuals Personnel... types are cages for radial bearings3, which constitute about 95 per cent of the production (ibid) A cage for a radial bearing and a complete radial bearing can be viewed in Picture 1.1 (a) (b) Picture 1.1 (a) Cage for a radial bearing (b) Complete radial bearing 3 The radial bearings are designed to carry load in radial direction of the shaft -7- -INTRODUCTION- 1.2 Problem discussion There are many ways... within the SixSigma organization are emphasized In European SixSigma Programs the importance ofa single individual is toned down and instead the participation of everyone is emphasized (Bergman & Klefsjö, 2001) 3.1.4 Critique to SixSigma Companies in Europe have been more skeptical to Six Sigma, than companies in the USA, although there are successful examples like ABB and Volvo (Magnusson et al., 2003) . SE
MARTIN LENNARTSSON
ERIK VANHATALO
-TITLES-
Evaluation of possible SIX SIGMA implementation
including a DMAIC project
- A CASE STUDY AT THE CAGE.
-ABBREVIATIONS-
LIST OF ABBREVIATIONS
ABB Asea Brown Bovery
ANOVA Analysis of Variance
ANOM Analysis of Means
C
p
Process Capability Ratio