Manufacturing Flexibility

1. Manufacturing Flexibility 2000/05/04 Yangja Jang

2. Contents • Introduction • Manufacturing Flexibility and Manufacturing Information System: Overview • Flexibility and responsiveness of machining environments • Nabil N. Gindy and Sameh M. Saad • Integrated Manufacturing Systems, 1998, Vol. 9, No. 4, 218-227 • Conclusion

3. Introduction • Market trends of manufactured products • Global competition • Shortened product life cycle • Increasing requirements for quality • Increasing need for product customization • Faster-paced advances in increasingly complex technology • Rapidly expanding options in materials and processes • Adapting strategy • Product cost and quality • Highest possible performance in an unpredictable environment

4. Introduction • Definition of Manufacturing Flexibility • Nagarur, 1992 “The ability of the system to quickly adjust to any change in relevant factors like product, process, loads and machine failure” • Upton, 1994 “The ability to change or react with little penalty in time, effort, cost or performance”

5. Introduction • Types of flexibility by Browne et al., 1984 Machine: the ease of making the changes required to produce a given set of part types Process: the ability to produce a given set of part types, each possibly using different materials, in several ways Product: the ability to changeover to produce a new product very economically and quickly Routing: the ability to handle breakdowns and to continue producing the given set of part types Volume: the ability to operate profitably at different production volumes Expansion: the capability of building a system and expanding it as needed, easily and modularly Operation: the ability to interchange the ordering of several operations for each part type Production: the universe of part types that can be produced

6. Introduction • Added flexibility types by Sethi and Sethi, 1990 Material handling: ability to move different part types efficiently for proper positioning and processing through the manufacturing facility Program: the ability of the system to run virtually unattended for a long enough period Market: the ease with which the manufacturing system can adapt to a changing market environment

7. Manufacturing Flexibility and Manufacturing Information System: Overview • Manufacturing flexibility as a strategic concern • Important facilitators of manufacturing flexibility • Skills • Information technology • MRP is being used as control logic to manage complexity (process and product) by larger enterprise • Difficulties in establishing and maintaining essential data • Application of inappropriate (complex) inventory logic to low value items • Limited ability of systems to cope with internal and external uncertainty • ROP, OPT and Kanban are reported to be more versatile than MRP

8. Contemporary Manufacturing Information System • Enterprise Resource Planning (ERP) • Customer-Oriented Manufacturing Management System (COMMS) Model by Farish (1993) • Support timely decision-making across multi-plant enterprise • has functionality for the vertical integration of suppliers and providing links with multiple plant-level execution systems • distinguishes between individual customers and their requirements • Manufacturing Execution System (MES) by Davidson (1994) • Demand is placed on the manufacturing system model by an MRPII and MES determines the most efficient use of available resources • Finite capacity scheduler, facilities to manage resources, produce work instructions, collect data on the status of labor and product costs and maintain process control

9. Contemporary Manufacturing Information System • Distributed Material Requirements Planning (DMRP) by Love (1995) • Logically separate MRPII systems to support the creation of an optimal enterprise wide production program • Each MRPII controls the individual cell in a single site • Each cell is both the customer and supplier of the others and local planning cycles are used to evaluate each cell’s ability to meet the orders placed on it by its customer cells • Cell’s compliance with the order requirement data is communicated to a customer cell which in turn evaluates the impact of any variance on delivery • This cycle is repeated until a satisfactory conclusion is achieved • Product Configurator • For make-to order, engineer-to-order products, pre-defining all the possible product options may not be practical • Reduce data redundancy and maintenance cost

10. Flexibility and responsiveness of machining environments Nabil N. Gindy and Sameh M. Saad Dept of Manufacturing Engineering and Operations Management, Univ. of Nottingham, UK Integrated Manufacturing Systems, 1998, Vol. 9, No. 4, 218-227

11. Introduction • Manufacturing responsiveness • Ability of manufacturing system to make a rapid and balanced response to the predictable and unpredictable changes • Purpose of development of appropriate measure and methods of assessment for manufacturing responsiveness • Better understanding of the inherent flexibility that exists within a manufacturing system (1) improve the utilization of available system resources to improve operational performance (2) improve the ability of a manufacturing system to cope with internal and external disturbances under tight due date targets

12. Conceptual Framework • Next generation manufacturing systems will be made up of relatively simple, distributed, autonomous but co-operating sub-systems or resource groupings organized as virtual factories • Rigid, static and hierarchical manufacturing system will be replaced by systems exhibiting great adaptability to rapid change which are able to produce low-volume, low-cost products • Manufacturing facility is treated as an objective-driven logical grouping of distributed resources which can equally termed “cell” or “factory” • The process of cell formation is dynamic, objective driven, self-optimizing and self-organizing

13. Conceptual Framework • Generic capability units (resource elements) • Are associated with sub-machine, machine, cell and factory levels • Describe the exclusive and overlapping capabilities of the available resources and hence indicate the similarity and uniqueness of manufacturing resources • Can be used during process planning, modeling, simulation and resource allocation to the cell • Cell/factory performance is assessed and measured in terms of resource elements

14. Conceptual Framework

15. Resource elements in machining environments FGS: form generating schema

16. Machine flexibility

17. Routing Flexibility

18. Experimental investigation • To compare the conventional machine-based scheduling approach with RE-based scheduling • Variety of operating conditions • 4 Dispatching rules • 3 Due-date assignment rules • Wide variety of due date tightness • 2 Demand patterns • 3 Machine breakdown rates

19. Scheduling environment

20. Due-date assignment approaches

21. Manufacturing Responsiveness • Responsive manufacturing system is a system that can be operated such that its objectives are achieved at the tightest due dates while minimizing tardiness • The ability to set tight due dates is one of the obvious measure of a responsive manufacturing system • Manufacturing Responsiveness Performance measure (k) • the level of due date tightness • Allowance added to the processing times of components which leads to zero mean tardiness • Simple measure for comparative assessment of the responsiveness of manufacturing systems • Increase in the value of k indicates a less system responsiveness

22. Simulation Results - Mean Tardiness

23. Simulation Results - Average Flow Time

24. Simulation Results – Load Distribution

25. Simulation Results – Effect of the demand pattern

26. Simulation Results – System Responsiveness

27. Conclusion • When a machine shop is represented as a set of generic capability units, • significant improvements in system performance measures and responsiveness can be achieved • it is useful for scheduling machining facilities • can achieve higher responsiveness in terms of setting and meeting tight due dates • Improve system’s ability in dealing with internal disturbances and external disturbances

28. Conclusion • Flexibility, responsiveness and quality will be the most important performance measures • The system to manage and control the manufacturing flexibility, responsiveness and quality will be required • Planning system • Control system including on-line scheduler • Product configuration and outsourcing must be considered during system design

29. References • R.Beach, A.P. Muhlemann, D.H.R. Price, A.Paterson and J.A.Sharp, Information systems as a key facilitator of manufacturing flexibility: a documented application, PP&C, 1998, Vol. 9, No. 1, 96-105 • R.Beach, A.P. Muhlemann, D.H.R. Price, A.Paterson and J.A.Sharp, A review of manufacturing flexibility, EJOR, 2000, Vol. 122, 41-57 • D.H.R. Price, R. Beach, A.P. Muhlemann, J.A. Sharp and A. Paterson, A system to support the enhancement of strategic Flexibility in manufacturing enterprises, EJOR, 109 (1998) 362-376 • Ram Narasimhan and Ajay Das, An empirical examination of sourcing’s role in developing manufacturing flexibilities, IJPR, 2000, Vol. 38, No.4, 875-893 • HITOSHI TSUBONE AND MITSUYOSHI HORIKAWA, A Comparison Between Machine Flexibility and Routing Flexibility, The International Journal of Flexible Manufacturing Systems, 11 (1999): 83–101 • W. Rocky Newman and Mary Jo Maffei, Managing the job shop: simulating the effects of flexibility, order release mechanisms and sequencing rules, Integrated Manufacturing Systems, 10/5 [1999] 266-275