Flexibility Measurement in Production Systems (eBook)

After a 3.5-year technical vocational training followed by 4 years of self-employment in the computer education field, Sven Rogalski studied commercial information technology (Wirtschaftsinformatik) at Otto-von-Guericke University in Magdeburg, Germany. In January 2006 he started working as a scientific researcher in the department Process and Data Management in Engineering (PDE) at FZI Forschungszentrum Informatik in Karlsruhe, Germany. Since then, he has worked in various industrial research projects. In March 2009 Sven Rogalski was appointed head of PDE department. Two months later, at the University of Karlsruhe, he successfully finished his PhD by evaluating production systems. In the same year he took over research field “Production and Logistics” at FZI.

Flexibility Measurement in Production Systems 4
Author´s Note 6
Contents 8
List of Abbreviations and Acronyms 12
Chapter 1: Introduction 14
1.1 Importance of Flexibility in Production 14
1.2 Current Trends in Handling Flexibility in the Field 16
1.3 Objective of This Book 19
Chapter 2: Analysis of the Field of Observation 22
2.1 Production Systems 22
2.1.1 Definition of Terms 22
2.1.2 Resources of a Production System 24
2.1.2.1 Production Equipment 24
2.1.2.2 Personnel 26
2.1.2.3 Material 27
2.1.3 Observation Levels in Production Systems 28
2.1.3.1 Workplace Level 29
2.1.3.2 Line Level 30
2.1.3.3 Segment Level 32
2.1.3.4 Factory Level 33
2.1.4 Change Drivers and Adaptation Objects of Production Systems 34
2.2 Flexibility of Production Systems 36
2.2.1 Application of Terms and Dimensions of Flexibility 37
2.2.2 Classification of Flexibility 40
2.2.3 Relevant Criteria for Flexibility Evaluation on Production Systems 43
2.2.3.1 Definition of Volume Flexibility 43
2.2.3.2 Definition of Mix Flexibility 44
2.2.3.3 Definition of Expansion Flexibility 44
2.3 Analysis of Relevant Evaluation Methodologies for Measuring Flexibility of Production Systems 44
2.3.1 Evaluation Methodology by Zäh and Müller 45
2.3.2 Evaluation Methodology PLANTCALCTM 46
2.3.3 Evaluation Methodology by Wahab, Wu und Lee 47
2.3.4 Evaluation Methodology by Schuh, Gulden, Wernhöner and Kampker 47
2.3.5 Evaluation Methodology by Ali and Seifoddini 48
2.3.6 Evaluation Methodology Desyma 49
2.3.7 Evaluation Methodology by Pelez-Ibarrondo und Ruiz-Mercader 50
2.3.8 Evaluation Methodology Penalty of Change 50
2.3.9 Evaluation Methodology by Haller 51
2.3.10 Evaluation Methodology FLEXIMAC 52
2.4 Need for a New Methodology and Requirements 53
2.5 Requirements for a New Evaluation Methodology 55
2.5.1 Fundamental Applicability 56
2.5.2 Flexibility Metrics 57
2.5.3 Production System Model 58
2.5.4 Software Implementation 59
Chapter 3: Introduction of a New Evaluation Methodology 60
3.1 Fundamental Approach for the Evaluation of Volume-, Mix- and Expansion Flexibility 60
3.1.1 Evaluation Proposal for Volume Flexibility 61
3.1.2 Approach to Evaluation of the Mix Flexibility 62
3.1.3 Evaluation Approach to Expansion Flexibility 63
3.1.4 Comparative Consideration and General Conditions of the Evaluation 65
3.2 Calculation Procedure for the Measurement of Flexibility 68
3.2.1 Base Algorithm 68
3.2.1.1 Defining the Calculation Parameters (Step 1) 69
3.2.1.2 Formulation of the Objective Function (Step 2) 71
3.2.1.3 Formulation of the Constraints (Step 3) 73
Time Conditions 73
Ratio Conditions 75
3.2.1.4 Formulation of the Linear Optimization Problem (Step 4) 79
3.2.1.5 Solution of the Optimization Problem (Step 5) 80
3.2.2 Flexibility Evaluation Method of Volume flexibility 81
3.2.2.1 Maximum Capacity 81
Calculation of the Maximum Capacity for the Whole System 81
Calculation of the Maximum Capacity for Subsystems 83
3.2.2.2 Break-even Point 85
Calculation of the Break-even Point for the Whole System 85
Calculation of Break-even Points for Subsystems 87
3.2.2.3 Calculation of the Volume Flexibility 90
3.2.3 Flexibility Evaluation Method of Mix Flexibility 92
3.2.3.1 Calculating the System-Optimal Production Profit 92
3.2.3.2 Calculating the Product-Limited Profit Optimum 95
3.2.3.3 Calculation of the Mix Flexibility 96
3.2.4 Flexibility Evaluation Methodology of Expansion Flexibility 98
3.2.4.1 Calculation of the Target Capacity 98
3.2.4.2 Calculating the Alternative-Specific Break-Even Point 100
3.2.4.3 Calculating the Expansion Flexibility 100
3.3 Definition of the Cost Accounting Reference Frame 102
3.3.1 Choice of a Cost Accounting Procedure 102
3.3.1.1 Decision Between Full Cost and Direct Cost Accounting 103
3.3.1.2 Choice of a Direct Cost Accounting Procedure 104
3.3.2 Determining the Hierarchies of Reference 104
3.3.3 Definition of Basic Cost Types 105
3.3.3.1 Workplace Level 106
3.3.3.2 Line Level 109
3.3.3.3 Segment Level 111
3.3.3.4 Factory Level 112
3.3.3.5 Graphical Summary of the Cost Types 114
3.3.4 Classification of Defined Cost Types in Cost Categories 114
3.3.4.1 Determining Variable Costs 114
3.3.4.2 Determining Fixed Costs 116
3.4 Concept of the Production System Model 118
3.4.1 The Object-Orientated Reference Model 118
3.4.2 The Principle of Inheritance of the Reference Model 119
Chapter 4: Practical Experience in the New Methodology 121
4.1 Implementation of the Evaluation Methodology 121
4.1.1 Software Architecture of ecoFLEX 121
4.1.2 Implementation of ecoFLEX 124
4.1.3 Functionality of ecoFLEX 126
4.1.3.1 Structure of the Program Window 126
4.1.3.2 Procedure of Flexibility Analysis 128
4.2 Case Study-Related Application Experience 130
4.2.1 Initial Situation at the Company 131
4.2.2 Object Area of the Case Study 131
4.2.3 Application of the Evaluation Methodology in the Context of the Case Study 134
4.2.3.1 Analysis of Volume Flexibility 135
4.2.3.2 Analysis of Expansion Flexibility 136
4.2.3.3 Analysis of the Mix Flexibility 138
4.2.3.4 Appraisal of Flexibility Analysis 140
4.3 Requirement Related Assessment of the Evaluation Methodology 141
4.3.1 Verification of the Software Implementation 142
4.3.2 Verification of the Production System Model 143
4.3.3 Verification of Flexibility Metrics 145
4.3.4 Verification of the Fundamental Applicability 147
Chapter 5: Summary and Outlook 152
5.1 Summary 152
5.2 Outlook 157
Chapter 6: Appendices 159
6.1 Basic Knowledge 159
6.1.1 Methods of Cost Accounting 159
6.1.1.1 Classification Criteria of the Cost Accounting System 159
6.1.1.2 Full Cost Accounting 160
Level 1: Cost Type Accounting 161
Level 2: Cost Centre Accounting 161
Level 3: Cost Object Accounting 162
6.1.1.3 Direct Cost Accounting 162
Direct Cost Accounting System Based on Variable Costs with Global Consideration of Fixed Costs 163
Direct Cost Accounting System on the Basis of Variable Costs with Differentiated Consideration of Fixed Costs 164
Direct Cost Accounting System on the Basis of Relative Direct Costs 166
6.1.2 The Simplex-Algorithm 167
6.1.3 Object Orientation 169
6.1.3.1 The Object Orientated Approach 169
6.1.3.2 Relevant Principles and Different Kinds of Representation in Object-Orientation 171
6.2 Additional Methods for Calculating of Flexibility 173
6.3 Demonstration of Further Aspects Regarding the Evaluation Methodology 175
6.3.1 Calculation of Energy Costs for Workplaces 176
6.3.2 Process Time as Part of the Cycle Time 177
6.4 Example of a Production System (for Illustrating Flexibility Calculations) 178
6.4.1 Graphical Structure and Terms 178
6.4.2 Calculating Parameters of the System 179
6.4.3 Expansion Alternatives for Segment S2 180
6.4.3.1 Alternative 1: Construction of a Redundant Production Line 180
6.4.3.2 Alternative 2: Construction of an Additional Workplace 181
6.4.3.3 Alternative 3: Modification of Workplaces 182
6.5 Calculation Parameters of the Expansion Activities from the Example Production System 182
References 184
Index 194