This paper provides investigative insights into the impact of operational flexibility on manufacturing performance in the metal parts fabrication process, The orders from customers for each item that arrive randomly in a planning period are periodically loaded for processing. They are launched at the beginning of the week. There often occurs a large difference in the processing workload among the machines, resulting in a long flow time for orders and low machine utilization, It is necessary to

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... mprove manufacturing perforrnance by introducing operational flexibility. Machine and routing flexibility are selected from various types of operational flexibility, because they are typical and elemental types of flexibility. Machine flexibility is the capability of a machine to perforrn different operations required by a given set of part types, and includes quick machine setup and jig changing. It allows smaller lot sizes, resulting in shorter manufacturing lead times, higher machine utilization, and lower inventory levels. Routing flexibility is the capability of processing a given set of part types using more than one route (alternative routing). It allows for eMcient scheduling due to alternative routing capabjlity, and can help handle contingencies such as machine breakdown and rush orders. The objective of this paper is to understand the influence ef operational fiexibility in a simulation-based investigation, by answering the following fundamental questions in the assessment of the two types of flexibility. ( 1 ) How does each type of flexibility affect manufacturing performance ? ( 2 ) How is manufacturing performance improved by introducing these flexibilities simultaneously? (3) How should the production planning and scheduling system be redesigned by introducing the operational flexibility, that is, how many lot sizes for each family should be set, and which scheduling rule should be adopted ? The flow time for each order and machine utilization ratio are adopted as criteria for manufacturing performance measurements. The results wiil enable manufacturers to gain better insight into the potential benefits of the different types of flexibility and their implementation.