Flexibility, integration and automation framework to assist CIM development: an IT effectiveness perspective

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FLEXIBILITY, INTEGRATION & AUTOMATION FRAMEWORK TO ASSIST CIM DEVELOPMENT :

AN IT EFFECTIVENESS PERSPECTIVE

By

ABHINAV AGGARWAL

Department of Mechanical Engineering

A Thesis submitted

in fulfilment of the requirement of DOCTOR OF PHILOSOPHY

to the

INDIAN INSTITUTE OF TECHNOLOGY, DELHI

HAUZ KHAS, NEW DELHI-110016, INDIA January, 1997

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Certificate

This is to certify that the thesis entitled 'Flexibility, Integration &

Automation framework to assist CIM development: An IT effectiveness perspective', submitted by Abhinav Aggarwal to the Indian Institute of Technology, Delhi, for the award of degree of Doctor of Philosophy, is a record of bonafide research work carried out by him under our supervision and guidance. The results obtained in this thesis have not been submitted to any other University or Institute for the award of any other degree or diploma.

Na ^fLAAnfo,

Dr. N. K. Tewari Professor,

Dept. of Mechanical Engg, Indian Institute of Technology, New Delhi - 110016

Dr. Subhash Wadhwa Associate Professor,

Dept. of Mechanical Engg,

Indian Institute of Technology,

New Delhi 110016

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Dedicated to

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Acknowledgements

I lack words to express my sincere thanks and gratitude to my guides Dr. Subhash Wadhwa and Prof. N.K. Tewari. Their guidance helped me to extend my cognitive boundaries and explore new horizons. Both Dr S. Wadhwa and Prof. N.K. Tewari guided me in the right direction and lend valuable advice to add value to this work. I am highly indebted to both of them. I acknowledge the support I received from faculty members of Department of Management Studies and Department of Computer Science and Engineering from time to time. Prof. U.R.K. Rao has been very supportive. I value his advice and his kind concern for research scholars. Several co-researchers and students of IIT Delhi contributed in their own way. Names of Nilanjan, Durgesh and Rajat deserve a special mention. I will always cherish my association with them and IIT Delhi.

In Dr. Subhash Wadhwa, I found an open and encouraging personality besides a source of immense knowledge and dedication. His involvement with this work was both exemplary, as well as emotional. Besides an excellent guide, he has been a great friend too. I owe my gratitude to his family also, who bore it with patience while he burned the midnight oil with me at IIT Delhi. His wife Dr. Amita Wadhwa had always been very supportive with her tremendous courage, maturity, and concern. His parents were very kind to attend to my numerous calls even at odd hours.

I have praise for CMC Limited as an organisation. It is the vision of its CMDs Dr.

P.P.Gupta and Dr. K.K. Krishnan Kutty that allows and encourages CMCites to pursue research activities. I thank Dr. V.Ramanan and Dr. P.Dasgupta for their kind support. My immediate colleagues Avtar and Meera had to bear it out with me in the office. They all provided the support I required.

I also wish to sincerely acknowledge the EU-supported DECSUPTO project with Dr.

Subhash Wadhwa that provided me with insights into the European state-of-the-art efforts in the area of IT in manufacturing. I had the opportunity of attending many valuable presentations by Prof. Jim Browne at ITT-Delhi that enriched my understanding of the subject. Dr. Wadhwa guided me through some of the ongoing works at CIMRU and GRAI and I benefited immensely from the opportunity.

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Finally, I owe this work to my parents and family. My father Late Satya Bhushan had a keen desire that all his children must acquire highest educational qualifications. My mother Mrs.. Urmila was keenly looking forward to this day. In her, I found an ocean of encouragement, patience and support.

My wife Sarita silently had to devote those extra hours needed to compensate for my absence from home. With her love, patience and support, I have been indebted to her forever. My son Pary and daughter Avi have been very matured and understanding for their age to keep me going. My sisters Dr. Mridu Vikram, Dr. Anu Ish and Dr. Hernia Rakesh have always extended their support in my endeavors.

Abhinav Aggarwal

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Abstract

Information Technology (IT) has a key role in the evolving manufacturing environment which is characterised by an increasingly change-based competition requiring timely and effective decisions. Computer Integrated Manufacturing (CIM) is considered an IT-focused platform through which the objectives of enhanced performance along with meeting diverse customer requirements can be achieved. Many efforts have been made towards defining CIM architectures and design and development methodologies. However, all of these implicitly assume a high level of IT affording virtually real time information flows and information processing at the operational levels within a manufacturing enterprise. For Indian industry, these appear to be highly capital-intensive solutions. What is needed is a framework that assists phased development towards CIM in a manner that IT effectiveness remains a pivotal issue. This should guide both the IT and Manufacturing System Specialists who typically do not fully appreciate the impact of each other's decisions on the performance of the overall system. This can result in potentially poor IT effectiveness.

Thus, to facilitate a better understanding, it is important to identify a few key dimensions of an integrated IT and Manufacturing System design that are major contributors to the manufacturing performance.

In this thesis, we propose and develop a framework based on flexibility, Integration and Automation (FIA) that might assist manufacturing companies to appreciate the IT effectiveness perspective of CIM development, especially at the operational level. The role of IT at any stage in this development may be viewed as the one that strengthens CIM effectiveness. In this perspective, it is suggested that Flexibility may be viewed as an ability provided by IT to identify and respond to the changes in an opportunistic manner to improve performance of the system. Integration is the linkage between entities and environments to provide status information. Automation is the speed of collecting and transporting data and its subsequent processing to provide the information for decision- making. A common understanding between IT and Manufacturing Specialists is proposed to be as follows: Flexibility implies that IT provides an opportunity to decide when to change and offers choices of the manner in which to change. Integration implies providing information about various entities to make good selection and choice decisions.

Automation implies the speed with which IT network allows information flow and processing.

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Though higher levels of Flexibility, Integration and Automation may appear to be desirable, these do not always result in significant improvement in overall performance and may not be cost-effective. A comprehensive framework should guide developments in this respect.

Manufacturing system specialists may need to design potential flexibility, integration and automation in the physical system while IT specialists may design the IT solution that exploits these through the appropriate levels of F, I and A in the decisional system. It is the balance between the two that will ensure overall effectiveness during any stage of CIM development.

To demonstrate the need to focus judiciously on F, I and A at the operational level, we define a shop-floor control model and develop a simulator called CIMSIM in this thesis.

The manufacturing system performance measure used is the Make Span Time. The IT options for FIA at various levels are defined along with their logical implications on the decisional system of shop-floor control. The experiments are first planned so as to study the impact of an increase in level of flexibility at a given level of Integration and Automation.

A number of alternative operating conditions are defined for the purpose. It is interesting to note that increased flexibility sometimes leads to deterioration in performance. Similar results are obtained for integration and automation. It is observed that the compatibility of F, I and A is important. Deviations from desired levels along any dimension (i.e. F, I or A) can cause a significant loss in performance. Thus, it is the synergy of FIA that contributes to higher performance. The implication of these results on industry is that a careful analysis is required at each stage of phased CIM development for determining the compatible F, I and A levels.

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1 Introduction

1.1 Role of Information Technology in CIM 1 1.2 Using IT to improve performance of manufacturing systems 2 1.3 Brief Overview of Recent Advances in IT 3 1.3.1 Relevance to Manufacturing Enterprise 4 1.4 An IT Effectiveness Perspective to CIM Design and Development. 4

1.4.1 IT Designer's Dilemma 6

1.5 Manufacturing Enterprise Re-engineering 8

1.5.1 The Challenge of Change Management 9

1.6 The need for a framework to assist CIM development. 11 1.7 An Information Technology Model for a Manufacturing Enterprise 13

1.7.1 Flexibility 13

1.7.2 Inter-operability 14

1.7.3 Portability 14

1.8 Overview of the FIA Framework 16

1.8.1 FIA as dimensions of CIM 16

1.9 Industrial need and Research Inspiration 20

1.10 Summary and Conclusion 22

Chapter 2

Literature Review

2.1 Introduction 23

2.2 Evolving Manufacturing Environment and Enterprise Evolution 24 2.2.1 Developing a Manufacturing Strategy 24

2.3 Computer Integrated Manufacturing 25

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2.3.1 CIM Design and Modelling Approaches 26 2.3.2 CIM Reference Models and Architectures 28 2.3.3 The need to integrate approaches 29 2,3.4 The concepts of a layered architecture 30

2.3.5 Observation 30

2.4 IT Effectiveness 30

2.4.1 Determinants of IT Usage 31

2.4.2 User Information Satisfaction 33

2.5 Improving the manufacturing enterprise 35

2.6 Flexibility 37

2.7 Integration 39

2.8 Automation 39

2.9 A Performance Evaluation Context for Manufacturing Systems 41

2.10 Performance Evaluation of IT network components 43

2.11 Findings of the literature Survey 44

2.12 Research Objectives 44

2.13 Research gaps identified 44

Chapter 3

Research Motivation and Thesis Proposal

3.1 Introduction 47

3.2 Research Motivation 47

3.3 Research Objective 50

3.4 Research Methodology 51

3.5 Thesis Outline 53

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Chapter 4

A Framework based on Flexibility, Integration and Automation for CIM development

4.1 Introduction 60

4.2 The FIA Framework to assist CIM Development 61

4.3 IT Perspective on FIA 63

4.3.1 Relationship with CIM-OSA 65

4.3.2 Relationship with NBS Model 66

4.3.3 Relationship with GRAI Methodology 66

4.4 Flexibility 67

4.4.1 The IT perspectives on Flexibility 68

4.4.2 Levels of Flexibility 74

4.5 Integration 76

4.5.1 IT Perspectives on Integration 77

4.5.2 Levels of Integration 81

4.6 Automation 83

4.6.1 IT Perspectives on Automation 84

4.6.2 Levels of Automation 85

4.7 A case study on determining F, I and A levels 88 4.8 Important Implication on IT design consideration 93

4.9 Measures of IT Effectiveness 97

4.10 Implications on IT Strategy 100

4.10.1 The Role of IT Strategy 100

4.10.2 FIA framework and IT Strategy 100

4.10.3 Other issues related to FIA levels and IT Strategy 102

Chapter 5

Development of Simulation Models to study FTA implication in shop floor control systems

5.1 Introduction 104

5.2 Production Control Hierarchy 104

5.3 Production Activity Control 105

5.3.1 The Scheduler 107

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5.3.2 The Monitor 108

5.3.3 The Dispatcher 108

5.4 Domain for FIA Adaptation 109

5.5 Development of CIMSIM Simulator 110

5.5.1 Computer Simulation 110

5.5.2 Key Elements to provide Scheduling Focus 112 5.5.3 Verification and Validation Issues 113

5.5.4 Modelling FIA in CIMSIM 114

5.5.6 Semi-Automated Shop Floor system 117

5.5.7 Key Features of CIMSIM 120

5.5.8 Assumptions 124

5.6 Modelling of IT related Delays 130

5.7 Modelling of FMS using CIMSIM 131

5.7.1 Typical Experiments using CIMSIM 131

5.7.2 Cases modelled in CIMSIM 132

5.7.3 Study and Result Analysis 133

Chapter 6

Some Studies on impact of Flexibility on IT Effectiveness

6.2 Motivation to study IT perspective on Flexibility 136 6.3 IT Effectiveness of Flexibility Models 138 6.3.1 Routing flexibility as a key Models Parameter 138 6.4 Experimenting with Flexibility Models 139

6.5 Limiting parts in the system 159

6.6.1 Routing Flexibility (RF) 171

6.6.2 Limiting Parts in the System 172

6.6.3 Machine Input Buffer Size 172

6.6.4 Dispatching / Sequencing Rule 173

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Chapter 7

Some studies on impact of Integration on IT Effectiveness

7.2 Motivation to study IT perspective on Integration 174 7.3 Integration related delays at shop floor 175

7.4 IT Effectiveness of Integration Modes 177

7.4.1 Scope as a key Model Parameter 178

7.5 Experimenting with Integration Modes 178

7.5.1 Information Timeliness as a key Model Parameter 192 7.5.2 Experimenting with Information Timeliness 192

Chapter 8

Some studies on impact of Automation on IT Effectiveness

8.2 Motivation to study IT perspective on Automation 205

8.3 IT Effectiveness of Automation Modes 207

8.4 Modelling Automation related delays on the shop floor in CIMSIM 208 8.4.1 Output Buffer Delay Requirements 209 8.5 Experimenting with data processing and transfer delays 209

Chapter 9

Study on combined role of Flexibility, Integration and Automation to address some issues for phased CIM Development

9.2 Comprehensive study of F, I and A 224

9.3 Motivation to study IT perspective on combined role of FIA 238 9.3.1 Combined role of FIA and Manufacturing Parameters 238

9.3.2 An IT perspective on FMS 239

9.3.3 Other Issues in Phased CIM Development 240 9.4 IT Effectiveness Perspectives on F, I and A 241

9.4.1 Flexibility 241

9.4.2 Integration 242

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9.4.3 Automation 243

Chapter 10

Conclusions and Scope for Future Work

10.1 Conclusions 246

10.2 Salient contributions of the present study 248

10.3 Limitations of the present study 249

10.4 Scope for Future Work 250

References & Bibliography

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Appendix I 270

Appendix II 271

Brief Resume of the Author 297

List of Research Publications 298