An approach to measure manufacturing system flexibility

The issue of flexibility has been becoming increasingly important. Flexibility, the adaptability to changes, has been crucial to lessen the shock of the impact of volume fluctuations, and to handle product variety changes. To take flexibility into adequate consideration in decision making, an operational measurement is needed. Yet, difficulties exist since flexibility has various dimensions, multiple types and is usually situation specific. Nonetheless, this thesis attempts to explore a generic approach to measure flexibility as an intrinsic property that enables the system to dynamically adapt to demand uncertainties. By drawing an analogy between manufacturing systems and electronic circuits, a new flexibility metric is developed based on system transfer function, namely the reciprocal of demand fulfillment time delay. For a manufacturing system which can be approximated as a linear shift-invariant system, its transfer function exists and can be derived from system’s input signal, the demand rate, and output signal, the production output rate, accessible data in real industry. To demonstrate the validity of the metrics, backlog capacity controlled system is taken as an example. Finally, the potential of including other flexibility types are discussed and opportunities for future research are suggested